Chapter 4 Building Styles and Construction
Platform Framing
**See picture Due to fire hazard and code compliance issues (not to mention the difficulty of getting good lumber 20 feet long), balloon framing is rarely used today. It has been replaced by platform framing. With platform framing, the studs run one story high. The wall sections are framed on the convenient "platform" consisting of the floor joists and subfloor. If there is a second floor, a whole new platform is erected on top of the walls. Then a second story is framed up with one-story studs. It also makes it more efficient to build as the second floor platform makes a perfect staging area to layout and frame the second-story walls - before they are erected. With platform framing, the studs are mounted vertically and have a sole plate nailed across the bottom. If the studs are 2 x 4 boards, they are installed 16 inches on center; if 2 x 6 boards are used, then they are typically put 24 inches on center. With 2 x 6s there is a bigger wall cavity, so more insulation can be inserted. At the top of the studs is a double top plate. Also, there is additional support needed over and around openings in the wall such as doors and windows. Headers are built over the openings to spread the load out to the sides and prevent the windows and doors from getting crushed or sticking.
Balloon Framing
**See picture Balloon framing was introduced around 1850 in America. It was made possible by the invention of the steam-powered saw mill which quickly and economically produced machined lumber. Also, the introduction of machinery to mass-produce metal nails and the advent of rail transportation were important factors. This technological revolution meant house-building was easier and quicker. We went from massive rigid frames to a matrix of relatively light structural members covered by a rigid skin. It required less skilled labor, as compared to notching complicated joints. It allowed architects and builders to break out of the mold of building basic rectangular shapes and made it easy and economical to create meandering houses with many corners. Balloon framing employs studs that run continuously from the sill to the rafter plate. The second story floor joists are hung and attached to the studs. Balloon framing gave good structural rigidity and was well suited for the plaster interior finishes of the day. One of the disadvantages was that the two-story cavities between studs were dangerous in the event of a fire. This could be ameliorated by installing horizontal "fire stops" made of 2 x 4's but by the 1930s and 1940s, balloon framing was outlawed in many municipalities.
Types of Residential Construction
**See picture Here is a page from the Marshall & Swift Residential Cost Handbook that describes the basic housing types.
Siding
Wood siding, both shingles and clapboard, was the standard in this country from the 1600s through the 1800s. In the last 50 years or so, there have been many innovations in lower maintenance siding materials. Many have the color baked in, and textures are available to resemble wood. As before, a list follows with sidings in approximate order of cost. Hardboard Wood clapboard Aluminum Vinyl Stucco Wood shingles EIFS Brick Stone A recent innovation in siding is fiber-cement. It has become popular throughout the country, but especially in the South and Southwest. It is composed of cement, sand and cellulose fiber to prevent cracking and increase strength. It comes in various styles, is textured to resemble wood, and can be painted in any color. The most well-known brand is HardiPlank, although there are other brands as well.
Legal Restrictions
You need to investigate possible legal restrictions as well. Check the local zoning ordinance. There may be setback requirements on the front, rear and sides that will restrict where you may place the building on the site. You may be left with only bad terrain that could render a parcel un-buildable. There may be height restrictions or view restrictions. You may not be able to build a structure higher than two stories, or 30 feet. You may be prohibited from blocking a neighbor's view. These restrictions may come from zoning ordinances or may be found in deed restrictions or subdivision regulations. There may be required distances between the well and septic system - most codes call for at least 100 feet. FHA requires that the well be a minimum of 50 feet from the septic tank, 100 feet from the septic drain field and at least 10 feet from a property line.
Manufactured Home
A manufactured home is defined as "A factory-built house manufactured under the Federal Manufactured Home Construction and Safety Standards Act of 1976, commonly known as the HUD Code." HUD maintains and enforces the code, which pre-empts all state and local codes. Congress gave HUD the authority because it involved interstate shipment, and they wanted to preserve access to affordable housing. No manufactured home may leave the factory unless it complies with the HUD Code and is released for shipment by an independent third party inspector, certified by HUD. Each HUD code manufactured home has a label on the exterior of each section containing a three-letter designation plus a six- or seven-digit number. This is a red, metal 2" x 3" tag that is pop-riveted to the exterior siding. Each HUD code manufactured home also has a serial number that is stamped into the foremost cross member of the frame. A data plate (also sometimes called compliance certificate) is installed inside the home with the name of the manufacturer, list of factory installed equipment, and the roof load and insulation zones. This is a paper sticker, which unfortunately is very easy for a property owner to remove.
Modular Home
A modular home is defined as "A factory-built house built in compliance with a building code other than the HUD Code. This usually means that the home is constructed to the standards of the state or local building code used by the governmental unit where the house is to be located. Note that the California Factory-Built Housing Program uses the term factory-built housing (FBH) in place of the term modular home." There are some similarities between HUD code manufactured and modular homes. Both are built by assembly techniques in factories and then transported to the site. Sometimes modular homes are even constructed on the same assembly line as HUD code manufactured homes. However, the manufactured home is constructed on a permanent steel chassis and has wheels and axles. It is meant to be hauled down the highway and arrives 100% finished. The sections are joined together at the site and it is complete. Most significantly, it is built to meet the HUD Code. A modular home is built in sections, called boxes, which are lifted onto a truck and transported to the site. The boxes are lifted off with a crane, or rolled off, onto the foundation. Then the boxes have to be joined and finishing work performed at the site. A modular home is built to meet state and local codes, not the HUD Code. Most modulars have conventional wood floor framing systems. However, there are some recently constructed with steel frames (called "on-frame" modulars). However, even with the steel undercarriage these are modular homes that have no wheels and axles, and they are built to state and local codes. Conversely, manufactured homes are built to the HUD Code and have wheels and axles, along with a steel undercarriage. They also will have the HUD label attached. Modular homes have no permanently-attached tags or labels that identify them as modular homes.
Private Water Supplies
About 40% of American homes have their own private water supply. Some areas with high water tables lend themselves to hand-dug wells or use of naturally occurring springs. Hand-dug means just that - someone stood there with a shovel and dug a hole. Artesian wells are ones in which the water is forced to the surface by hydrostatic pressure and overflows all by itself. In some cases a point (metal pipe with sharp end) is driven into the ground until water comes to the surface. Because these types of supplies lie near the surface, they are often subject to seasonal fluctuation and dry spells. They are also subject to pollution from surface runoff, unless protected and enclosed. They may require filters or purification systems. Deeper wells can be drilled or pounded into the ground. Heavy plastic or steel casing is used until bedrock is reached. After that, the hole that is bored into the rock will be self supporting and will not need casing. The depth to find potable water in adequate quantities can vary enormously. Local well drillers may be able to give you estimates of typical water depths and flows in an area. Ask how much it costs per foot for wells - cased and uncased. A normal, acceptable water flow would be about 3 to 4 gallons a minute. In some areas, even with a deep well, it is impossible to attain such a yield. It may be necessary to pump water more slowly into a storage reservoir to satisfy demand when needed. Piston pumps use suction to lift the water. Submersible pumps are preferable. They go in the bottom of the well and push the water up. However, it is harder to maintain or repair them, as they have to be pulled up to the surface for servicing.
Septic Systems
About one-third of the houses in America use private septic systems. Older systems consisted of merely a cess pool. This was just a hole dug in the ground and filled with rocks or loose blocks so wastes would filter into the ground. In modern septic systems, the sewage leaves the house through a 4-inch line and goes to the septic tank. Older tanks were made of steel - most today are concrete or fiberglass. Steel tanks generally have a life of 25 years or so, depending on conditions in the ground. The size of the tank is generally linked to the bedroom capacity of the house. For example, a 1,000 gallon tank may be used for four bedrooms and 1,250 gallon tank for five bedrooms. The tank serves as a settlement area. The solid wastes sink to the bottom and are mostly consumed by bacteria. The bacteria are introduced when the tank is new by inserting some yeast. By the way, the bacteria can easily be killed by bleaches or certain detergents. The remaining sludge needs to be periodically pumped out. The liquid wastes, or effluent, leaves the tank as new wastes enter, through a 4-inch solid line that goes to a junction box. Here the water is diverted into several directions and the water flows out into the drainage field or leach field through perforated tiles that allow the water to seep slowly out. The total amount, or lineal feet, of drain tile needed is determined by the character of the soil, as revealed through percolation ("perc") tests. The perforated drainage tile is laid in trenches filled with gravel, to promote drainage. The tile should be only 1 to 3 feet beneath the surface. The water will eventually filter down through the gravel and the ground underneath it and be purified. This is the same principle as a sand and gravel filter for a swimming pool. Most water will eventually seep in the underground water table and be reused. Some of the water will leach its way to the ground's surface and be evaporated. Over time, a drainage field may become saturated with water and unable to function. Then it may have to be excavated and replaced or extended. If the soil conditions are particularly bad or space is limited, an above ground mound system may have to be employed. Sand and gravel are mounded up to create a favorable environment for drainage. This may or may not entail a sewage pump to pump the water up into the mound. Some systems also employ storage tanks where the wastes are collected and then injected under pressure with a pump, when the storage tank is full. If you have to resort to systems like this, they will work, but can be expensive. They may run up to $20,000 or more. Newer and more advanced systems are being designed and built all the time. Some of these systems can be prohibitively expensive to install and/or maintain.
Site Preparation-Physical Considerations
After all the planning is done and we figure out the perfect spot to place the house, there are still some things to be accomplished before the excavator arrives. Some of the things involved are physical in nature and some are legal. Some physical tasks that need to be done include clearing the building site of rocks, trees and stumps, and any debris. Then the property needs to be rough graded. The topsoil should be stripped off and saved to put back later. A sub-base for the driveway and parking area needs to be installed - at least sufficient to support a concrete truck and building material delivery trucks. A temporary "service drop" needs to be arranged from the power company, and an electrician dispatched to set the meter and temporary power panel. Power will be required as soon as actual construction starts. Another good idea is to run water and telephone lines to the site, if possible. A drainage ditch should be dug leading away from the foundation area, to evacuate any water that may accumulate.
Amperage
Amperage is the total amount of electricity that you have available. In small houses with light loads and perhaps gas appliances, you might be able to get by with 60 amps. One hundred amps is a more normal minimum amount. A house with electric heat would require at least 200 amps. It is not unusual today to find large houses with 300 amps or more. Be careful with trying to estimate the amount of amperage that is present in a house. You can read the stated amount on the cover of the electric box or that is stamped on the main cutoff. But that will only definitely tell you the capacity of the main panel box! They may have installed a 200 amp box, for future expansion, and only installed a 125 amp service. Adding up the totals of the amps indicated on each breaker will not be fruitful. Typically, more are installed that than the total amount because you are not expected to have everything on all at once. The only definitive way to tell the amperage is to examine the size of the entrance cable. Remember the hose analogy - certain size wires can carry only a prescribed volume of electricity. The size or gauge of the entrance cable will enable you to estimate the amperage of the service.
Roof Framing
As the weight of the roof presses down, it tries to push the side walls out. The various components of the framing system hold the walls together. Conventional rafter systems consist of boards that are set at an angle and meet at the ridge. There may or may not be additional cross pieces to help combat the stresses. Roof truss systems resist the spreading stresses and transfer all the weight to the outside walls. They are about three to four times as strong as a conventional rafter system, and none of the interior walls are load bearing. They are usually factory built to custom specifications, trucked to the site and erected with cranes.
Types of Commercial Construction
Commercial buildings differ in type of construction. Here is the breakdown that is recognized by Marshall & Swift in their Marshall Valuation Service. They classify the construction characteristics by type of framing, walls, floor and roof structures, and fireproofing. They categorize commercial buildings as: Class A - fireproofed steel frame Class B - reinforced concrete frame Class C - masonry or reinforced concrete Class D - wood or steel studs Class S - pre-engineered structural; members
Ventilation Methods
Common methods of ventilation include: Attic fans Kitchen fans Vents - basement and crawl space Attic - ridge vents, perforated soffits Louvers Cupolas Mechanical air exchangers
Concrete Block Walls
Concrete block walls are laid one block at a time. This type of wall takes a little more time and skilled labor. When completed, the block walls are not as strong or waterproof as poured walls, but cost less. One or two coats of parging, consisting of troweled-on Portland cement, are applied to the exterior of the wall for moisture control. Then, there should be an additional layer of tar or other waterproofing material. Reinforcing mesh is laid between the courses and rebar may be applied vertically, through the holes in the blocks. Sometimes the holes are filled with concrete. Long walls may need additional support from pilasters. In addition, insulating material, such as Vermiculite, may be poured into the blocks. Some recent blocks are constructed of lighter weight concrete, and some have particles of insulating material, such as Styrofoam, built in.
Pipes
Distribution lines have traditionally been copper, after bad experiences with galvanized iron pipes. Drain lines have traditionally been cast iron. In recent years there has been general acceptance of plastic pipes, but they are still prohibited in some building codes. "Black Plastic" polyethylene is flexible and permitted for cold water use only. It should not be utilized for distribution lines within the house, but works well to bring in the water from the supply, i.e., from the well or the public water system. Polybutylene pipe is similar but has had poor acceptance with many codes due to earlier fitting problems. Rigid plastic pipe includes PVC and CPVC. PVC is approved only for cold water but CPVC can be used to carry hot or cold water. Plastic pipe has largely replaced cast iron pipes in the DWV systems. However, white PVC pipe is not accepted by all codes. Black ABS plastic pipes are stronger and are generally acceptable today. There were some earlier class action suits due to cracking in some ABS pipes manufactured between 1984 and 1990. In today's new construction, cross-linked polyethylene (known as PEX) plumbing is becoming more common. This flexible plumbing product allows for long plumbing runs with fewer (or no) joints or fittings, which means less chance of leaking.
Electric Heat
Electricity is sent through a resistor, which causes it to heat up. Air passes over the heated surface and warms the room by convection. In some cases fans are also employed to move the air around. Electric heat has many advantages; there is a thermostat in every room, it is clean, there is no furnace or chimney needed, and virtually no maintenance. It is practically a perfect heating system except for one factor - in most parts of the country it is the most expensive system to operate because of the cost of the electricity itself.
Windows
Everybody loves windows. It's nice to have all that light in the house, and they can help with ventilation. But from an insulation standpoint, they are a disaster! A single pane of glass has an R factor of 0.5. Two panes, with an air space, make about R-1.5 and even triple panes with two air spaces have an R factor of only about 2.5. You might as well have a big hole in the wall that lets out all the hot air. If nothing else, you may want to have fewer windows on the north side and more on the south. You can increase the insulating capacity in modern windows by filling the air cavity between the panes of glass with a gas. Typically Argon gas is used - it is inexpensive, non-toxic, non-reactive, clear and odorless. Where the space is thinner than usual, Krypton gas may be employed. (Don't tell Superman.)
Below-Grade Areas
The Fannie Mae Selling Guide goes on to state: "Rooms that are not included in the above-grade room count may add substantially to the value of a property-particularly when the quality of the finish is high. The appraiser must report the basement or other partially below-grade areas separately and make appropriate adjustments for them on the 'basement and finished areas below-grade' line in the 'sales comparison analysis' grid."
Soil Conditions
The bearing capacity of the soil itself is important when constructing a house. Bearing capacity can vary from one to eight tons per square foot. If the soil is sandy or not very strong, wider footings and additional supports such as pilings may be required. Soils lose strength in proportion to their water content. Some soils may be unstable, such as a peat bog, or subject to slippage, such as landslides or sinkholes. The composition of the soil itself can vary dramatically. It can be sampled by test borings, or you may refer to soil maps. Soil maps are available from the Natural Resources Conservation Service. The maps show soil types superimposed over black-and-white aerial photographs of the county. They provide charts and other information on production capabilities for agriculture & forestry. They also contain information on soils' capability for structural support-building foundations and suitability for septic systems. They are based on aerial mapping rather than site-specific soil testing, and thus are considered a guide rather than the last word. However, they can be very helpful for general research. Check them out at http://websoilsurvey.nrcs.usda.gov/app/ The drainage capacity of the soil can be a crucial factor. In percolation tests, you pour water into a hole and stand there and time how long it takes to drain away. The results of the "perc" test will determine if there is suitable drainage and the size of the drain field that will be required for a septic system. In some rural areas, "perc" tests have to be done before a building permit is issued. If the drainage capacity of the soil is too poor, other arrangements may have to be made. Above ground or "mound" systems may be installed. A mound of varying size gravels and sands is piled up to create a favorable environment and then the drain field lines are laid in that. It may also require a pump to pump the sewage up hill to the mound. There may also be restrictions on building in a flood hazard area. You need to check the FEMA maps. Or there may be restrictions on financing. FHA will not allow new construction in a Special Flood Hazard Area (SFHA). Some designated wetland areas may prohibit building in the wetland or in the buffer zone around it. Some areas may have a low water table, which will mean deeper wells and perhaps seasonal water shortages. Some areas have a high water table, and the water is near the surface of the ground. This makes it easier to drill for water but may lead to chronic moisture problems in a basement or crawl space. Local well drillers may be able to give estimates of typical water depths in an area. There may be rock underground. The good news is that it would provide a stable base if you dig down to it. The bad news is that it may require blasting or specialized equipment if the rock is near the surface. Ledge rock can support up to 20 tons per square foot and bedrock up to 80 tons per square foot. Drilled wells need to use steel casing until the drilling enters bedrock. Therefore, rock near the surface will save on drilling costs. A negative factor might be the presence of radon, which occurs from the decay of uranium rocks.
Fiber-Cement Siding
Fiber-cement siding is gaining rapid acceptance for both residential and non-residential new construction. Its features include: Low maintenance Moisture resistant Won't crack, rot, buckle or de-laminate Termite proof Non-combustible 50-year transferable warranty You have to handle it differently, because of its composition. You cut it with a carbide tipped saw (with dust catcher) or shears and fasten it with hand or pneumatic driven non-corrosive nails or screws. You leave a joint at the edge and caulk to allow expansion if it meets wood - or use vinyl trim. This type of siding can be applied over wood frame and sheathing or insulation board. It can also be applied directly over masonry block or concrete.
Warm Air Heat
For many years, the warm air furnaces were "ductless". They were known as gravity furnaces. As the air was heated it rose, through a floor register, and as it cooled, the air fell back down by the force of gravity (actually, convection) to be re-heated and sent up again. Grates were cut in the floor of the second story in an attempt to get heat upstairs. Some heat did ultimately find its way up there, but the system was not very efficient or comfortable. The next generation of heating systems had ducts and multiple registers in the floor, but there were no fans. The air simply rose when warmed. Because of its configuration, it was known as an octopus system. Here is a photo of an old octopus heating system. Some of these systems were subsequently updated with fans.
Framing Systems
Framing systems undergo tremendous stresses and must be engineered to handle them. The entire weight of the roof presses down on the walls and tries to spread the walls outward. The walls carry the weight of the entire structure down to the foundation and ultimately the footings. For over a thousand years, the framing system utilized was the post and beam system. This consists of large vertical posts that support horizontal beams. The posts and beams were joined together by various interlocking joints, such as mortise and tenon, and then secured by wooden pegs. **See picture
Geothermal Heat Pumps
Geothermal systems usually employ high density polyethylene pipe. It is buried four to six feet deep for horizontal applications and may run from 100 to 500 feet deep for vertical applications. The pipes are filled with water or a non-toxic antifreeze solution. They are unobtrusive, low maintenance systems and can give you free domestic hot water as a bonus. According to the EPA, GeoExchange systems are the "most energy efficient, environmentally clean, and cost effective space conditioning systems available." Residential systems do cost more to install initially, but because of their greater efficiency, the cost can be recouped in 2 to 10 years. They may become more competitively priced as technologies improve. There are four basic systems, depending on the amount and type of land you have and the presence or absence of water. Two systems extract heat energy from the ground and two from water. Once you get down 4 or 5 feet, the temperature of the ground stays between 50 and 55 degrees year-round. Water holds heat well and even in the winter, when the ground surface freezes, it is warmer below. End of Page
Floor Framing
Girders are the main support beams and are set in pockets that were formed in the top of the end walls of the foundation. Steel girders are often used; they are very strong, but they are also heavy and sometimes difficult to work with. Wooden girders may be fabricated by nailing together three or more wooden planks. Usually these members have plywood spacers for additional strength and are glued as well as nailed. There are also engineered wood girders, with trademarked names like Glulam and Microlam. In most cases, the girders are also supported by posts. The size of the girders can be calculated from beam formulas, span tables or local codes.
Gross Building Area
Gross Building Area (GBA) is distinctly different from gross living area. GBA is defined as "Total floor area of a building, excluding unenclosed areas, measured from the exterior of the walls of the above grade area. This includes mezzanines and basements if and when typically included in the market area of the type of property involved." GBA is used in measuring 2- to 4-unit residential properties. It is also sometimes used in measuring commercial buildings, such as office buildings. Depending on the situation, it may include some unfinished areas or common areas such as hallways. As we will discover on the next page, Fannie Mae's definition of GBA does not include unfinished areas, but does include common areas.
Gross Living Area
Gross Living Area (GLA) is defined as "Total area of finished, above-grade residential space; calculated by measuring the outside perimeter of the structure and includes only finished, habitable, above-grade living space. (Finished basements and attic areas are not generally included in total gross living area. Local practices, however, may differ)." On the next page, we will address the guidelines of Fannie Mae related to measurement and calculation of GLA. It is important to remember that these requirements only apply to the appraisal of single-family homes for mortgages that are going to be sold to Fannie Mae.
Electric Heat Pumps
Heat pumps are simply reversible air conditioners. They can heat in the winter and cool in the summer. They use a refrigerant to pick up and discharge heat. This refrigerant is naturally a liquid but turns into a gas when it absorbs heat. Compressing the liquid helps it absorb heat, then the gas is run through a condenser to cool it down, give off heat, and become a liquid again. For years, Freon R-22 was the refrigerant of choice in home air conditioning; however it is no longer permitted for use in new construction because it has been shown to damage the Earth's ozone layer. Today's environmentally-friendly refrigerants are manufactured under the brand names Puron, Genetron AZ-20, and Suva 410A. Heat pumps use very little energy and have few moving parts. The problem is that they are inefficient once the outside air gets below about 40 degrees. In northern climes, they need back-up systems for heating, but will work well for cooling. They are a relatively slow form of heat as the heated air entering a room is considerably cooler than that supplied by a hot air heating system.
Sill Plates
In either form of construction, "J" shaped anchor bolts are installed when the wall is completed. This will be the method to attach the masonry to the first piece of the wooden structure, the sill plates. **See picture The sill plates are usually 2 x 6 or 2 x 8 wooden boards, depending on the size of the foundation wall. Before they go down on top the foundation wall, there should be an insulation strip or sill sealer installed. End of Page
Slab-on-Grade
In most of the South and Southwest, the monolithic slab-on-grade foundation is preferred over basements or crawl spaces. It is the quickest and cheapest way to install a foundation. Frost heaving is not a consideration in these regions. It is essentially one giant footing, so the weight is distributed over its entire surface. A standard slab is only four inches thick, but then is thickened an extra eight inches on the edges and wherever concentrated loads will occur; such as under a partition, bearing post or chimney. Before the slab is poured, the soil base must be leveled and prepared. The outer edge of the slab is formed up with boards, just as for a footing. A poly vapor barrier is laid on the ground and wire mesh reinforcement added. The mechanicals must be carefully planned and installed before the slab is poured. Water and electrical lines may be run through plastic conduit to facilitate future replacement. The perimeter should be insulated with rigid insulation for at least two feet from the edge. Some of the heat loss in a building occurs out through the slab. Also, you need to guard against freezing of pipes in the slab. The interior of the perimeter walls will be filled with compacted gravel and/or sand, depending on the nature of the soil.
Building Styles and Construction
In the early 1600s, the first structures build by American colonists consisted of one room, with a dirt floor. By 1650, there were a few houses being built with two rooms, side by side. By about 1670, we saw the first two story houses being constructed, with two rooms on each floor. From then on, until the early 1900s, almost all American houses were two-story structures, in varying styles. The exceptions were a few one-story log houses in the frontier states. Around 1900, we saw the first one-story homes emerging such as Frank Lloyd Wright's "Prairie Style" homes. These were primarily one floor, but were large, architect-designed custom homes. Some had small upper stories. The first one-story homes for the masses were the "bungalow" homes introduced from about 1910 to 1930. This was stretched into the "ranch" style home in the 1940s and 1950s. From the 1950s until today, we have seen five basic housing types - based on the number of stories. They are the Ranch - 1 story Cape Cod - 1-½ story Two-story Split level - multi levels Split entry (sometimes called a split foyer, bi-level, or raised ranch) - one story with finished basement (Note: Marshall & Swift refers to this type as a "two story bi-level")
Air Conditioning
In the southern parts of the country and in the tropics, houses might have no heating systems. In these locations, the air conditioning system is the most important. We discussed the basics before. As a liquid turns into a gas it absorbs heat - as it cools it gives off heat. There will be cooling units inside the house. They may be located in walls, basements or attics. The condenser will be located outside - ideally on the north or east side. Cool air is distributed by fans through a duct system. It may be combined with a hot air heating system and use the same ducts. The ducts should be insulated. A/C systems need to be properly sized for the building according to: Building volume Window area Insulation R factors Appliance heat output Solar orientation Humidity levels in climate Check the Seasonal Energy Efficiency Rating (SEER) label for the air conditioner. Acceptable Minimum is 10 - maximum is 18.
Hot Water Heat
In this system, water is heated in a boiler and sent through pipes to each room, where it gives off heat through convectors. As the water is heated, it expands and temporarily goes up into the expansion tank. The water is pulled through the lines by a circulating pump. Some old steam systems were converted to hot water and utilized the original radiators. Modern systems usually employ baseboard units. The water runs through copper pipes and heats up aluminum fins that are attached to the pipe. This sets up convection currents, air passes around the fins, and is heated. Hot water heat is a relatively efficient system, as water retains heat for a long time. It is cleaner than hot air and less drafty. It is easy to zone it for different areas. Disadvantages are that the baseboard radiators restrict furniture placement and the pipes could freeze and burst if the power goes off. Also, the water in the pipes is susceptible to air blockage and may corrode the pipes.
Evaluating Above-Grade Room Count
It is important that you carefully measure the GLA of residences. Fannie Mae says in its Selling Guide, Section B4-1.4-14: "The most common comparison for one-unit properties is the above-grade gross living area. Appraisers must be consistent when calculating and reporting finished above-grade room count and square footage for the gross living area above-grade. A level is considered below-grade if any portion of it is below-grade - regardless of the quality of its finish or the window area of any room. A walk-out basement with finished rooms would not be included in the above-grade room count. For units in condo or co-op projects, the appraiser must use interior perimeter unit dimensions to calculate the gross living area. In all other instances, the appraiser must use the exterior building dimensions per floor to calculate the above-grade gross living area of a property. The following must be observed when calculating and reporting above-grade room count and square footage for the gross living area: Only finished above-grade areas can be used in calculating and reporting of above-grade room count and square footage for the gross living area. Garages and basements, including those that are partially above-grade, must not be included in the above-grade room count."
Perimeter Drainage
It is important to drain water away from the house so it doesn't collect against the foundation and ultimately seep in. Drains made of 4-inch perforated plastic pipe are laid outside and below the level of the footings. They are laid in crushed stone and covered with a fabric filter to keep dirt from clogging the pipes. The lines must be carefully graded away from the house and continue for a reasonable distance. Water seeps into the pipes and is carried away by gravity.
Floor Joists
Joists are horizontal structural members, placed on edge, which carry the house loads to girders and sills. The thickness, width and spacing are determined by the live loads placed on them. They commonly are 2 x 10's or 2 x 12's. The joists are laid perpendicular to the girders. They may rest on top of, or be at the same height as, the girders. The outside ends of the joists rest on top of the foundation wall and are butted into the header joist.
Site Preparation - Legal Considerations
Legal considerations that need to be accomplished include: Obtain a building permit Check applicable codes Building codes Fire codes Check environmental regulations Wetlands Protected areas Hazard areas Check flood plain Curb cut permit or driveway permit (if needed)
Masonry Construction
Masonry construction is also popular, in many varieties: Brick Stone Concrete block Poured concrete It is sturdy, durable and low maintenance, but generally costs more than frame construction. Masonry construction has been around longer than frame construction. Brick construction may consist of solid brick, where the wall is laid in two layers with interlocking bricks. The bricks provide the structural support as well as the exterior veneer. The bricks themselves can be laid in different patterns and come in many colors. This was common many years ago, but is less common today. A cheaper alternative is to apply a brick veneer, which is a layer of brick over a frame wall. It may be applied to all four walls or maybe just the front facade. A newer product is called thin bricks. It consists of brick material that is only about an inch thick and is applied over a frame wall.
HVAC Systems
Next we will investigate systems that will keep us warm or cool. These are referred to as HVAC systems, which stands for Heating, Ventilating, and Air Conditioning. Our bodies have their own heating systems, but our comfort range is pretty narrow. It varies from person to person, but might range from 65 to 85 degrees. We can add or shed some clothing, but beyond that to keep comfortable in a house we might need to turn on the heating or cooling systems.
Plumbing Systems
Plumbing systems encompass two main systems: the distribution system and the drain/waste/vent (DWV) system. In addition, there may be a third sub-system with hot water or solar heating. The distribution system brings water, under pressure, into the house - usually through a ¾-inch or one-inch line. This divides before going through the water heater into cold and hot water distribution lines that run to each fixture or appliance. Better quality systems use ¾-inch main lines and ½-inch branch lines. Lesser quality installations use ½-inch throughout. Good plumbing practice postulates: Keep piping runs as short as possible Put the water heater close to the main point of use Insulate supply pipes - both hot and cold In cold climates, do not run supply pipes in exterior walls and unheated areas Design the system so it can be shut down and drained easily Install shutoff valves on every fixture riser pipe The drainage system carries off waste water. Grey water from the shower, sinks, and laundry is carried off in drain lines and may vary from 1-½ inches to 3 inches. Black water from the toilets is taken away by soil lines, which are usually 3-inch lines. "U" shaped, water-filled traps are installed under each fixture to keep sewer gases from venting back into the house. The drain system funnels waste water into a stack (3 or 4-inch diameter), which leads out to the sewer or septic system. The stack must be vented to the outdoors to allow gases to escape through the roof and to prevent water being siphoned from the traps.
Subflooring
Prior to the 1970s, subflooring usually consisted of 1" x 6" tongue and groove boards laid diagonally for more strength. Today it is almost always 4' x 8' sheets of plywood or oriented strand board (OSB). One-half inch may be an acceptable minimum, but 5/8 inch or 3/4 inch is much more desirable. A good way to combat floor squeaks and improve structural rigidity is to glue the plywood down to the joists and use tongue and groove plywood.
Roof Covering
Roof covering has the basic function of keeping out the rain and snow. It can also serve aesthetic purposes and adds texture and color to a house design. Here is a list of popular roof coverings arranged in order of their costs - from low to high. Composition roll roofing Composition shingle Built-up rock Metal Wood shakes or shingles Cement fiber shingle Clay tile Slate Copper Most new construction today employs fiberglass composition shingles. The average life ranges from 20 to 35 years, depending on the thickness and weight of the shingles. The life may be less in the South, where the sun is more intense. The weight of the shingles is a literal term describing the weight of shingles that are sufficient to cover 100 square feet, or a square. For example, if you place a square of 240-pound shingles on a scale, they will weigh in at 240 pounds. Newer, low maintenance products being used include metal roofs and fiberglass tiles that look like clay tiles. Metal roofs in particular have gained a significant share of the residential roofing market over the past 5 to 10 years.
Sheathing
Sheathing is applied to: Strengthen the structure Provide a nailing surface for siding Combat air infiltration Form a moisture barrier Provide some insulation The most common sheathing is insulating foam sheathing, which can provide up to R-8 insulation. Plywood or OSB board is sometimes still used, particularly when strength and rigidity are required. Then sheathing paper, such as asphalt building paper, or vapor and wind barriers such as "Tyvek", are applied.
Insulation
Some materials transfer energy more quickly and are called conductors. Good conductors include such things as metal and stone. If you sit on a stone bench, your backside gets cold because the stone quickly conducts away the body heat. Poor conductors, or insulators, include plastic and air. That's why we move electricity through a copper wire encased in plastic. We can insulate a wall with cellulose fibers with lots of air spaces. Down parkas work well because of the air spaces in between the feathers. If they get damp or the down gets matted, it doesn't insulate as well. Heat energy will flow from warm areas to cold areas. We can retard the flow, but can't stop it. The measure of resistance to heat transfer is called an "R" factor. To give some perspective - an inch of wood has an R factor of about 1. Depending on where you are, the desired R factors may be something like R-13 in the floors, R-19 in the walls and R-30 in the ceilings. That would take a lot of wood! Thankfully, modern insulations have been developed that will help us accomplish those factors without having to build walls that are two feet thick.
Stucco
Stucco is a lime-based mortar finish applied to a wall. It can be easily applied over concrete blocks. Two or three coats are sprayed or troweled on. Stucco can be applied over frame walls, with the proper preparation. Wire mesh is first attached to solid sheathing. EIFS Exterior Insulation and Finish Systems (EIFS) is sometimes known as Synthetic Stucco. This is a combination of insulation and exterior finish in one process. The exterior surface is quite water resistant, but there have been many problems with water infiltration where they meet other components such as windows, doors, roofs and chimneys. This type of exterior finish has been used in recent years, primarily in the South. In some areas, this type of finish has a bad reputation for leaking. The system is composed of 5 five layers: Substrate Adhesive Insulation board Base coat with embedded fiberglass mesh Finish coat in desired color
Electrical Systems:
The best analogy is to compare electricity running through a wire to water flowing through a hose. The volts are the pressure that is pushing it (similar to pounds per square inch of water pressure) and the amps are the total volume that will fit through the hose (similar to gallons per minute of water). Power will be delivered from a utility pole to a building via three wires - two wires are "hot" and the third is neutral. The wires may run through the air as three separate wires, or as a braided triplex wire. Of course, they may also be buried underground. If you measure the voltage across both hot legs, it will be 240 volts. Between either hot leg and the ground, it will be 120 volts. These are nominal voltages, but they vary a little between 110 and 120 and between 220 and 240 volts. We need more power - more pressure - to run certain items. Electric dryers, electric ranges and heavy duty power equipment runs on 220/240 volts. Normal receptacles, lighting, small appliances, computers, etc. run on 110/120 volts. Certain things like doorbells and thermostats require little in the way of power and have transformers that reduce the power to only 12 volts. Twelve volts is a minimal amount of pressure and will not harm you. 110 volts will give you a nasty shock, but 220 can kill you!
Foundation Walls
The earliest foundations were made of stone (loose or mortared) and brick. Today most foundations are constructed of poured concrete or concrete block. The most common is poured concrete, although in some areas of the country, concrete block may be more common. Wood foundations have been used successfully in Canada for more than 40 years, but have received a lukewarm reception here in the U.S. They have proven to be durable, easy to erect, and come in panels that are insulated and easy to finish on the inside. They are constructed of pressure-treated wood. They probably will never see wide-scale usage until they experience better press and more general public and lender acceptance. With poured concrete walls, forms are erected which usually are steel braced sheets of plywood. Rebar is inserted into the openings, and then the forms are filled to the top with concrete. Anchor bolts are set into the top of the wall, to later fasten down the sill plate. When poured, the concrete on the bottom of the wall flows down into a keyway - a slot that was created in the top of the footing when it was poured.
Wiring
The earliest type of wiring in a house was called knob and tube. It consisted of bare copper wires strung between porcelain insulators or standoffs. You may still encounter some of these, but they are outdated and banned by many codes. In the 1940s and 1950s, BX or armored cable was common. There were two wires and a ground inside a metal jacket that protected the wires. It was a good system for interior wiring of a house, but the cable was hard to work with, hard to cut, and didn't bend very well. Aluminum wiring was used for a short period of time in the mid-50s, due to a shortage of copper during the Korean War. It proved to be a fire hazard, in many instances, as the aluminum was subject to oxidation where it joined the electric boxes and receptacles. Since the 1960s, the most popular wires have been plastic-coated non-metallic wire (known as Romex, which is actually a brand name). These are copper wires encased in plastic sheathing, which is flexible and gives the wires adequate protection from contact with conductors or other wires. Let's stop here and check your understanding.
Foundation System
The foundation system serves three purposes. It distributes the weight of the building over the ground, anchors the building to the ground, and protects the wood in the house structure from decay and insect attack. It is made up of three components The soil bed Footings Foundation wall or piers A stable foundation system depends primarily on proper footing depth and good drainage. Footings typically consist of concrete poured inside wooden or plastic forms. It goes without saying that they need to be level! Footings need to be at least a foot below average frost penetration levels. This "frost line" varies all over the country, from zero in Key West, Florida, to eight feet or better in Lake Placid, New York. The footings need to be on undisturbed, unfilled ground. Footings should be twice as wide as the foundation wall and as deep as the wall is wide. Depending on the soil conditions and local codes, they may or may not have metal reinforcing rods (rebar). Small footing pads also need to be constructed on the interior of the foundation wherever posts will be employed to support the floor beams, as seen in the center of the photo below.
Modern Forced Warm Air Heat
The modern forced warm air system employs fans to move the air around and ducts to supply heat to every room. The air can also be filtered or humidified. Forced air heat warms a room rapidly and the ducts can be used for air conditioning. It is the most common heating system in new construction today. The disadvantages are that it can be noisy and it blows hot, dusty air around. The ducting system makes it difficult to retrofit.
Site Planning
The rest of this chapter will be devoted to residential construction issues. Before one can even begin to build a house, though, one needs to select a site. Let's talk about site planning. There are lots of decisions you need to make before you even think about breaking ground. You only get one chance to set the building on a site, i.e., one chance to get it in the right place. If a structure is misplaced on a site (and that's unfortunately fairly common) it can hinder the value of the property for the rest of its life. One basic item is the direction of the sun. To take advantage of the sun, the lot should ideally be sloped to the southeast. South is good, east is better than west, and you should avoid a north slope. Take advantage of the way the sun travels seasonally. Overhangs can protect windows when the sun is high and hot in the summer and allow the winter sun to come in when it is lower in the sky. The house itself can be oriented to take advantage of the sun. In northern climes, south-facing windows can give a lot of solar gain in the winter, and north-facing windows should be minimized. The home does not have to face true south. If it faces within 25 degrees either side of true south, it will still receive 85% to 95% of available solar energy. Deciduous trees may be employed on the south to shade that side in the summer and let the sun through in the winter. Of course, in southern climes, the south side should be protected from the sun. The west side should employ plantings or screens such as trellises or overhangs to protect against the hot afternoon sun. The prevailing wind patterns should also be studied. In many areas the wind is primarily from the west, so the north and west sides should be screened if possible. This can be accomplished with plantings or perhaps by taking advantage of a hill or slope on that side. In warmer areas, the south and west sides should be left open to take advantage of cooling breezes. These little touches - which are easy to overlook - can make a big difference.
Roof Slope
The slope of the roof is described as a precise relationship of the rise over run. The rise is how high it goes up vertically over a certain horizontal run. For example, if the roof rises 4 inches as it goes 12 inches sideways - the slope or pitch of the roof is 4 over 12 or 4/12.
Topography
The slope or topography is also an important issue. The easiest site to build on is a level one; however then you have to build in drainage. This may consist of open, above-ground swales or ditches, or it may involve underground drainage systems. A gently sloping lot is preferable. Perhaps you can take advantage of building on a high spot or move some dirt around to re-grade, if necessary. Sloping lots may involve extensive re-grading, filling, terracing, and retaining walls. If it is quite steep, there may be extensive runoff after storms and little usable land around the house for lawns and entertaining. This may be compensated for with decking. A site may be relatively level, but if it is much above or below the road level, it will require work for adequate access. There may be a steep driveway or switchbacks required. There may be steep or long sets of steps to walk up or down to the house.
Low-E Glass
The sun's energy passes through glass as "short wave radiation" and is absorbed by carpeting, furniture, etc. Then it is transmitted as heat energy or "long wave radiation", which wants to flow from warm air to cool and much will pass back out through the windows. Low Emittance (Low-E) glass has a coating on the inside to reflect it back. Different types of coating may be applied to admit more or less solar gain, depending on the climate. In the summer or in warmer climates it is desirable to have less sun come through. The advantages of Low - E glass are: Better heat insulation Reduced carbon dioxide into the atmosphere Reduced condensation on the interior
Architectural Styles
There are a number of different architectural styles found throughout the United States. Identifying and describing these myriad styles is beyond the scope of this course. You can start with a two-story type of house and make it a Colonial style, a contemporary style, or a Spanish style. These are all two-story houses - but they sure are different styles. Style can be influenced by: Type and texture of exterior finish Colors Roof style Roofing materials Window types Building shape Ornamental details Shutters Dormers Cupolas Corner boards In 2011, Fannie Mae and Freddie Mac created the Uniform Appraisal Dataset (UAD) which is a set of standardized reporting requirements used in residential mortgage lending appraisal reports. One of the UAD protocols is that the appraiser must identify the architectural style of the subject property and comparable sales. According to the UAD protocols, "Valid descriptions include, but are not limited to, 'Colonial,' 'Rambler,' 'Georgian,' Farmhouse'. Do not use descriptors such as 'brick,' '2 stories,' 'average,' 'conventional,' or 'typical' as these are not architectural styles. Design style names may vary by locality. The appraiser should report the name of the design style that is applicable within the local market area." Several resources I would recommend if you want to learn more about architectural styles are: Houses, Third Edition, Henry Harrison, Real Estate Education Company, Dearborn Publishing Company American Shelter, Lester Walker, The Overlook Press A Field Guide to American Houses, Virginia and Lee McAlester, Alfred A. Knopf, Inc. The American House, Mary Mix Foley, Harper and Row A Field Guide to American Architecture, Carole Rifkind, New American Library
Heating Systems
Up until about 1840, all houses were heated by fireplaces. Then metal wood-burning stoves were introduced. Usually they were employed in several different rooms. The modern "central" heating system with one central furnace didn't appear until around 1880. At first, they too burned wood, but evolved through coal, oil, gas, electricity, etc.
Ventilation
Ventilation goes hand in hand with insulation. Moisture is the enemy of insulation. When insulation gets moist, it packs down and the insulating air spaces get compressed, thereby reducing its effectiveness. Moisture inside a house must be contained and evacuated through proper means of ventilation. Moisture in the building structure can lead to mold growth, peeling paint and rotting wood. As houses have been built more "tight" in recent years, this is more important than ever. Super-insulation may be counterproductive, if the house can't breathe. There should be a vapor barrier on the heated side of a wall so that warm, moist air inside the house is prevented from entering the wall cavity. Once inside the wall, it cools, condenses and soaks the insulation. Moisture in a house is produced by many things: People breathing - an average person breathing puts 2.8 pounds of moisture in the air each day Plants Showers - ½ pound of moisture in the air from each shower Hot tubs, pools Dishwashers Washers and dryers Cooking - 4.7 pounds of moisture per day in the average home
When appraising 2-4 family residential properties, Fannie Mae, Freddie Mac, HUD/FHA and VA require an appraiser to use gross building area.
When appraising 2-4 family residential properties, Fannie Mae, Freddie Mac, HUD/FHA and VA require an appraiser to use gross building area. Fannie Mae says in its Selling Guide, Section B-4-1.4-14, "Gross building area: is the total finished area including any interior common areas, such as stairways and hallways of the improvements based on exterior measurements. is the most common comparison for two- to four-unit properties. must be consistently developed for the subject property and all comparables used in the appraisal. must include all finished above-grade and below-grade living areas, counting all interior common areas such as stairways, hallways, storage rooms, etc. cannot count exterior common areas such as open stairways. Fannie Mae will accept the use of other comparisons for two- to four-unit properties (such as the total above-grade and below-grade areas) provided the appraiser: explains the reasons he or she did not use a gross building area comparison, and clearly describes the comparisons that were made."
Privacy Areas
When siting a home, a homeowner or developer needs to plan ahead to include areas for outdoor activities. There are three potentially separate zones to be considered: A private area for family activities, such as a pool, patio, deck, play areas such as swing sets, horseshoe pits, etc. This is usually in the rear yard and may be fenced in or screened with shrubbery or trees. A public area, usually in the front yard, which contains the guest entrance and driveway. A service area that allows for semi-public area for deliveries, trash removal, meter readers, fuel trucks, mail delivery, etc.
Radiant Heat
With hot air or hot water systems, the air is heated and circulated around and eventually transfers heat to a person. With radiant heat, waves of radiant energy are transferred directly to your body. You can feel the warmth - like sitting by a wood stove or getting warmed by the sun. Also, everything else in the room gets warmed - the furniture, for example - which then warms the air for a period of time afterwards. Radiant heat was utilized in the 1950s and 1960s but the technology was not too advanced and there were maintenance problems. We are seeing a resurgence of popularity today in new construction - but obviously, it's hard to retrofit. There are two types of radiant heating systems in common use - electric and hot water. In electric radiant systems, electric cables may be installed in the ceiling or a slab floor. In hot water systems, hot water pipes are usually buried in a slab but may also be run between conventional floor joists. If in a slab, the concrete also gets heated and radiates heat. Electric radiant heat has the advantages of having no boiler, no chimney, no parts or valves to wear out and no pipes to freeze. Hot water radiant heat costs less to operate, but it can be expensive to install. New types of plastic pipe can withstand freezing and corrosion. Because the water only needs to be heated to between 90 and 120 degrees, a small boiler or hot water heater can be utilized at considerable energy savings. Zoning is easy to install. Radiant heat is efficient and has less temperature extremes from floor to ceiling. You will be comfortable at temperatures six to eight degrees less than with other forms of heat. Radiant heat advantages are: Doesn't dry out the air No air or dust blown around No convectors or registers to complicate furniture arrangement Less heat loss to outside air infiltration Can reduce the heat load in a well insulated house by 25% to 35% over conventional convective systems
Floor Trusses
Within the last 30 to 40 years, we have seen an increased use in computer designed floor trusses in residential applications. They have greater strength and allow long clear spans without girders or posts. The open web design allows easy installation of plumbing and wiring.