Materials and methods chapter test 2
vapor barrier
materials added to walls and attic areas to help reduce drafts and prevent moisture from getting into a home
Channel section
a steel or aluminum section used for light bracing and framing task.
Polyvinyl Chloride (PVC)
(Thermoplastic) made from PVC resins, plasticizers, stabilizers and reinforcing fibers or fabrics. concerned over toxic chemicals have raised questions over its use.
TPO
(Thermoplastic) new to North America, good resistance to heat and UV radiation, seams can be heat welded.
low-range sealants
(caulks) have limited elongation (stretching and squeezing) capabilities up to plus or minus 5% of the joint. used to fill minor cracks or nonmoving joints. cure by evaporation of water
thermal emittance
- A measure of a material's capacity to radiate infrared heat energy and cool itself as its temperature rises. 0-1 scale. a high number indicates a cool roof.
Flat-Seam Metal Roofing
-Typical pan size: 18 in. x 24 in. -Attachment cleats are nailed to decking and rolled into the flat pan seams -minimum slope is 3:12 For low slopes, pans can also be joined by soldering
high range sealants
-polysulfides, polyurethanes, and silicone with extensive elongations (50%-100%). site mixed with two components to chemically cure. (do not shrink upon curing)
roof deck
The structural surface that supports the roofing system
typical components of green roofs
1 Plant materials 2 Growth medium (soil) 3 filter fabric, to confine soil particles 4 Drainage/aeration/water storage layers 5 Roofing or waterproofing membrane 6 Rigid insulation All components of a green roof system above membrane are preassembled in trays The trays (typically 2 to 4 feet in dimension) are delivered to the jobsite ready to be installed They are easy to specify, easy to install, and easy to remove or adjust at a later date Cost associated with initial installation and additional structural support Complicate repairs to the roof membrane Ongoing maintenance
5 forces for water to penetrate exterior wall
1)Gravity 2)Momentum 3)Surface tension 4)Capillary action 5)Air pressure differences/wind currents page 799
In order for water to penetrate an exterior wall
1)Water must be present 2)There must be an opening for the water to enter 3)There must be a force to move the water through the opening
Sealant Installation
1.Clean joint of oil, dirt, oxide, moisture, form release compound, or other contaminants 3.Apply primer to improve adhesion if necessary 4.Insert backer rod in joint 5.Apply sealant to joint 6.Properly tool the sealant
minimum roof slope required by building codes
1/4" per foot. (1in 48) or 2%. achieved by sloping beams or building up insulation in varying heights.
minimum recommended slope for architectural metal roofs
1:12 (8%) for standard seam and 3:12 (25%) for batten seam
Extensive Green Roof
2-6 in. soil depth Low-maintenance, drought-tolerant plants Moderate roof loads. (up to 30") require irrigation and garden maintenance higher maintaince. must plan for load and saturated water weight up to 12-35 PSF or more. typically flat, but can slope 12:12 (100%) with soil retention measures.
Grenfell Tower
24 June 2017 West London 24 story residential building 72 deaths $200 million in property loss Major renovation in 2015-2016 Combustible composite rainscreen cladding system installed without firestopping
Thermal Bridging
A component of higher thermal conductivity that conducts heat more rapidly through an insulated building assembly, such as a steel stud in an insulated stud wall. can cause condensation leading to mildew and shit
area divider
A curb used to partition a large roof membrane into smaller areas to allow for expansion and contraction in the deck and membrane. do not extend below the surface of the roof deck
Solar Reflective Index (SRI) (page 704)
A measure of how well a material rejects solar heat; the index ranges from 0 (least reflective) to 100 (most reflective). ASTME1980
Stick system
A metal curtain wall system that is largely assembled in place Pros - have advantage of low shipping bulk and high degree of adjustability to unforeseen conditions Con - assembled on site under highly variable site conditions Storefronts are typically stick systems
Sheet Metal Roofing
A metal roofing material of either copper, galvanized iron, aluminum, or terne-plate, a lead and tin coated steel.
alloy
A mixture of two or more metals
Low Slope roof
A roof that is pitched at an angle so near to horizontal that it must be made waterproof with a continuous membrane rather than shingles; commonly and inaccurately referred to as a flat roof. Less than 2:12 slope or 17%
ductile
A term used to describe a material that can be pulled out into a long wire.
flashing
A thin, continuous sheet of metal, plastic, rubber, or waterproof paper used to prevent the passage of water through a joint in a wall, roof, or chimney.
Backup wall
A vertical plane of masonry, concrete, or wood framing used to support a thin facing such as a single wythe of brickwork
Movement - thermal expansion and contraction (secondary)
Accommodate movements due to changes in temperature Differential thermal expansion and contraction of inside and outside of cladding Differential thermal expansion and contraction of cladding relative to frame
Movement - Structural (secondary)
Adjust to structural movements in frame due to: Building foundation settlement Shortening of columns Wind and earthquake forces can cause racking effect Long term creep of concrete Failure of exterior wall system can result in: Broken glass Buckled cladding Broken cladding attachments Sealant failures
Inside Glazed Curtain Wall Systems
Allows glass installation and replacement from inside the building Inside glazing is more convenient, safer, and more economical for tall buildings It requires a more elaborate set of extrusions
Exterior wall building code standards
American architectural manufacturers association (AAMA) 501 methods of test for exterior walls
"Off-The-Shelf" Systems
An "off-the-shelf" curtain wall system is available as either an outside glazed system or an inside glazed system Some systems allow glazing from both the inside of the building and the outside of the building
Mineral Surface Roll Roofing
Asphalt roofing products manufactured in roll form. 36-inch wide rolls with and 108 square feet of material. Weights are generally 45 to 90 pounds per roll. inexpensive and used primarily on utility and agricultural buildings. last 6- 15 years cons: Thermal expansion or shrinkage of wood causes ridges Can be installed on a low slope roof (minimum slope: 1:12)
baked enamel
Baked enamel finish consists of spray-applied acrylic or polyester polymers before passing through an oven Produces a very high-gloss finish Inexpensive and available in a wide range of colors
Movement - moisture expansion and contraction (secondary)
Bricks, building stone, concrete and wood change dimension due to moisture content and can cause problems which need to be taken into account
Controlling Light
Control sunlight to balance between useful illumination and detrimental effects of UV light Control can be provided by balancing the number of windows, exterior shading devices, types of glass
Column-Cover-and-Spandrel-Systems
Emphasizes the structural module of the building rather than creating its own grid on the facade Advantages and disadvantages are similar to the unit system A custom design must be created for each project because there is no standard column or floor spacing for buildings Special care required in detailing spandrel panel support to ensure that panels do not deflect when loads are applied to spandrel beams of the building frame
Weathering gracefully secondary
Exterior cladding must weather gracefully Dirt and grime should not detract from the aesthetics Cladding must resist oxidation, UV degradation, corrosion of metallic components, chemical attack, and freeze thaw damage
very thin stone facing
Extremely thin sheets (1/4") of stone stiffened with a structural backing such as a metal honeycomb and mounted as spandrel panels in an aluminum mullion system Very thin sheets of stone may be used as facings for precast concrete curtain wall panels When specifying the thickness of stone for any exterior cladding application, the designer should work closely with stone supplier
safing
Fire stop material in the space between floor slab and curtain wall in multi-story construction.
Sheet metal thickness
Higher gauge numbers correspond to thinner sheets! Contemporary standards refer to thickness in decimal inches. exception copper which goes by weight. page 700.
Pressure-equalized wall design
Includes the creation of an air tight plane or air barrier The air barrier is protected from direct exposure to the outdoors by an unsealed layer known as the rainscreen (metal panels in this example) Between the air tight barrier and the rainscreen is a space known as the pressure equalization chamber (PEC) Sloping surfaces in the rainscreen counteract surface tension and gravity Installation is simple and forgiving PEC doubles as a drainage space (similar to the cavity in a masonry wall) PEC may be divided into narrow compartments by vertical and horizontal channels
mortar mesh
Inserted into the wall cavity to catch mortar droppings and prevent obstruction of weep holes at bottom course
Controlling the radiation of heat
Interior surfaces can cause discomfort due to radiant heat transfer in summer and winter Shading devices, thermal insulation, thermal breaks and appropriate glass can be used to control radiant heat
Controlling sound
Isolate the inside of the building from noises outside and vice versa Requirements will vary by type of building and its location
panel System
Made up of homogenous units that are formed from metal sheet May or may not be glazed at the factory Advantages and disadvantages are similar to the unit system Production involves higher tooling costs of a custom made die or mold, which makes it advantageous only for buildings that requires a large number of identical panels
building code for exterior walls
Major impacts of building codes on the design of exterior wall is in the following areas... Structural strength Fire resistance Energy efficiency Structural Requirements Strength and stiffness of wall system and adequacy of attachment Fire Resistance Fire resistance rating of exterior materials Smoke development rating of materials Firestopping Energy Requirements Minimum thermal resistance (R-Value) Maximum levels of air leakage Glass/glazing performance requirements
Prefabricated Reinforced Brick Panel Curtain Walls
Masons construct the panels while working comfortably at ground level in a factory. Horizontal and vertical reinforcements are installed as required Panels are rigid and need no structural backup A steel stud backup wall is required to carry thermal insulation, electrical wiring, and an interior finish layer
Thermal insulation
Material which is used to reduce the amount of energy transferred by heating from an object.
Fluid applied Roof members
May be sprayed or rolled. It may have glass of fiber reinforcing. Seamless and easily formed. good for complex shapes. can be sprayed over deteriorating roofs.
Thermal Insulation below the rood deck (low slope)
Mineral or glass fiber batts are installed either between framing members or on top of suspended ceiling assembly. (building code requires a ventilated space between insulation and underside of the roof deck to dissipate vapor) pro:economical and easy. con: leaves the roof deck and membrane exposed to the full range of outdoor temp fluctuations vapor barrier is applied to the warm, conditioned side of the roof insulation to control insulation.
Bituminous Roof Membranes
Mostly made from asphalt. Typically assembled from multiple, overlapping layers of materials. There are two general types: 1. Built up roof membranes (BUR) 2. Modified bitumen roof membranes
primary functions of the exterior wall.
PRIMARY: keeping water out, controlling light , controlling air leakage, controlling water vapor, controlling the radiation of heat, controlling the conduction of heat, controlling sound, SECONDARY: resisting wind forces, adjusting to movement, resisting fire, weathering gracefully,
unit systems
Preassembled framed units with glazing Takes full advantage of factory assembly Pro - minimizes on-site labor Cons - units need more space for shipping and more protection from damage when compared to stick systems
Gypsum Sheathing Board
Prevent buckling, twisting, and lateral wind. Made out of more resilient material than regular wall board.
keeping water out
Prevent the entry of rain, snow, and ice into the building Water is driven inwards by many forces such as wind, air pressures and gravity Water problems tend to be more acute in tall buildings
controlling air leakage
Prevent unintended passage of air between indoors and outdoors Air leaks waste conditioned air, carry water through the wall, and allow noise to penetrate
extrusion process
Process using that starts the same as injection moulding but the heated thermoplastic polymer is pressed through a die to create a continuous cross section.
Thermal insulation above roof membrane
Protected membrane roof (PMR) insulation installed above the membrane. Pros: membrane protected from extreme heat and cold, the membrane is on the warm side of the insulation (immune to blistering) does not need a vapor retarder must work when exposed to water: extruded polystyrene foam is most commonly used (laid loose or adhered to a membrane by asphalt Cons: moisture may cause the insulation to lose R value not suitable for climates with lots of rain, cold weather, repairs to the membrane are more time consuming and expensive.
Aluminum Curtain Walls
Protects itself against corrosion Accepts and holds a variety of attractive surface finishes Can be fabricated into elaborate shapes by a process called extrusion Is light and strong
Resisting wind forces (secondary)
Provide adequate strength and stiffness to sustained pressures and suctions due to wind Pressure and suction will vary by height and location of the cladding elements such as corners
barrier wall system
Relies solely on the EIFS coating layers and joint sealants to protect against water penetration
Controlling water vapor
Retard the passage of water vapor by diffusion or condensation Water vapor could cause staining, loss of insulation value, corrosion, or decay
roofing and the building codes
Roof flame spread rating classified as Class A, Class B, or Class C (ASTM E108) Class A - Roof coverings that are effective against severe fire test exposure Class B - Roof coverings that are effective against moderate fire test exposure Class C - Roof coverings that are effective against light fire test exposure The International Building Code (IBC) requires roofs to meet class B requirements on most buildings of construction Types I, II-A, III-A, IV, or V-A Roofs for single-family homes and small utility buildings are generally allowed to be non-classified Examples of materials that meet each flame spread classification?
Cool roofs
Roofs with high solar reflectance or solar reflective index (SRI) experience lower temperatures. Reducing solar heating of roofs reduces cooling loads on the building, increases the life of roofing materials, and reduces urban heat island effects. Modified bitumen low-slope roof membranes surfaced with reflective-white coated granules White liquid-applied membrane coatings
temperature for sealants
Sealant are best applied in moderate tempuratures Sealants installed in cold weather will have to stretch less but compress more and vice versa for sealant installed in hot weather
sealant proper contact
Sealant should only contact two sides of the joint. If it contacts the third side then the effective width of the sealant is reduced, resulting in extra strain and tearing A bond breaker material is used to prevent the sealant from coming in contact with more than two sides
Standing Seam Metal Roofing
Seams are typically ¾ to 1inch tall Cleats are nailed to decking and rolled into the seams Minimum recommended slope - 1:12
Constructability (secondary)
Should be easy to install Must be sufficiently "forgiving" in design to allow for a lifetime of trouble-free performance
die casting
Similar to permanent mold casting except that the metal is injected into the mold under high pressure.
shingles
Small, overlapping roofing units with staggered vertical joints made of wood, asphalt, slate, clay, concrete, metal, or other materials
Photovoltaic systems
Solar panels that convert sunlight directly into electricity. PV materials directly convert sunlight into electricity PV panels can be mounted to a building's roof or exterior walls PV systems can be used to supplement power or as part of a stand-alone or "off-grid" system Estimating the potential "payback" for a particular PV system requires an analysis of the initial cost, solar exposure, power needs, and cost of utilities
prefabricated EIFS
Steel studs are welded together to make a backup frame Rigid sheathing is screwed to the frame and finished with EIFS The finished panels are lifted and bolted to the building frame
steep roofs
Steep roofs (those with a pitch greater that 2:12) have better drainage performance. Shingles are often used on steep roofs, these are easy to install and repair. However, these roofs are susceptible to ice dams forming.
Cold Form Metal framing
Studs, joist and c channels made from light gauge steel
prescriptive requirement
The ICC incorporated these requirements for steel-framed residential construction; often allows builders to design and construct light gauge steel-framed houses without and engineer or an architect
relative humidity
The amount of water vapor in the air at any given time is usually less than that required to saturate the air. Expressed as a percentage.
Resisting Fire secondary
The exterior wall of a building can interact in several ways with building fires There are a number of building code provisions relating to the construction of building exterior walls systems with respect to fire safety
Outside Glazed Curtain Wall Systems
The glass must be installed or replaced by installers working from scaffolding or staging on the outside of the building Outside glazing systems utilize simple, less expensive shapes Usually reserved for buildings up to three stories in height
Monolithic Stone Cladding
The panels are fastened directly to the frame of the building The weight is transferred to two steel support plates by means of edge pockets that are cut into both sides at the stone mill Each panel is stabilized by a steel angle strut Joints are closed with backer rod and sealant A non structural backup wall is required
slate shingles
These shingles are delivered to site split, trimmed to size, and punched/drilled for nailing. They form a fire resistant, long‐lasting roof for high quality buildings. high price, last 60 to 80 years.
Drainage-Wall or Water-Managed System
These systems utilize a layer of drainage matting behind the foam insulation that captures water and conducts it to flashings and weeps at the base of the wall The IBC requires a water-managed system where EIFS is applied over wood-framed buildings of any residential occupancy type
Posttensioned Limestone Spandrel Panels
Thick blocks of limestone may be joined with adhesives into long spandrel panels and posttensioned with steel tendons (cables) The assembly is self- supporting between columns This is a relatively costly type of panel
Light Gauge Steel
Thin sheet metal folded into a stiff shape and used as a structural member.Equal to wood construction,
powder coating
This process uses an electrostatic charge to coat the metal product. Once coated, the product is baked in an oven to produce a smooth, high-gloss finish. Provides superior edge coverage This type of finish is relatively low in cost, durable, and available in a wide range of colors
Batten-Seam Metal Roofing
Wood battens are placed between the pans Seams are formed on each side of the batten Slight tapering in the battens allows for expansion and contraction of the sheet metal Minimum recommended slope - 3:12
ASTM C920 types
Type S - Single component (no jobsite mixing required) Type M - Multicomponent (must be mixed on the jobsite) Grade P - Pourable (aka "self-leveling") and are easily installed in horizontal paving joints Type NS - Nonsag (used for vertical wall joints) Use T - Traffic (made to tolerate wear and physical abuse associated with vehicular traffic) Use NT - Nontraffic (not suitable for traffic exposure) Use I - Immersible (sealants designed for applications where the sealant will be submerged)
Wood Shingles (sawn) and Shakes (split)
Typically used woods are those that are decay resistant. They're usually tapered so that they can fit easier as you go up the roof. Shakes are thicker than shingles. These types of roofs can be treated for improved decay resistance. They're vulnerable to fire, but they can be chemically treated to help. decay-resistant species like red cedar, white cedar, and redwood are used. (last 15-25 years)
load bearing external walls
Until late in the 19th century all large buildings were built with loadbearing exterior walls Most were built with brick or stone masonry They were poor thermal insulators and required large foundations Modern day loadbearing walls are thinner and lighter. They have higher strength masonry and concrete; components such as insulation, flashing, air barriers, and vapor retarders. Loadbearing masonry and concrete walls are economical for low and medium-rise buildings.
Polymer-based or "Class PB" EIFS
Uses a low-density expanded polystyrene bead foam insulation A glass fiber reinforcing mesh that is applied to the outer surface of the foam A base coat formulated primarily from either portland cement or acrylic polymer A finish coat of textured granules in acrylic polymer Relatively thin coating is flexible and resistant to cracking Most commonly specified type of EIFS in North America
Polymer-modified or "Class PM" EIFS
Uses a slightly higher density extruded polystyrene foam insulation A metal reinforcing mesh that is applied to the outer surface of the foam A base coat of a relatively thick portland cement A finish coat of portland cement with acrylic modifiers A thicker coat is more resistant to physical abuse Also known as "hard coat" EIFS
Stone Panels Mounted on a Steel Subframe
Vertical support members of grid system are erected first The horizontal support members are aluminum shapes that engage in slots in upper and lower edge of each stone Backer rods and sealants fill the joints between the stone Nonstructural back-up wall of steel studs and gypsum sheathing is constructed within the frame of the building to provide air barrier, insulation, electrical wiring and interior finishes
sealing joints on an exterior wall
Why? To prevent passage of air and water through the exterior membrane while allowing for movement Where? Between curtain wall panels Between dissimilar materials (i.e., metal and masonry) How? Two primary methods... Gunnable joint sealants Solid joint sealant materials
Exterior Insulation and Finish System (EIFS) elements
a Layer of plastic foam insulation adhered or mechanically fastened to a backup wall A reinforcing mesh that is applied to the outer surface of the foam A base coat of a stucco like material which embed the mesh An exterior finish coat of a similar stucco like material that is troweled over the base coat
Web Stiffener
a metal rib used to support the web of a light gauge steel joist or a structural steel girder against buckling
hot-dip galvanizing
a method of galvanizing in which a steel member or assembly is dipped into a bath of molten zinc
electrogalvanizing
a method of galvanizing, in which an electric current is used to deposit zinc from a liquid bath onto steel
Thermal break
a plastic connector in a metal frame system that prevents excessive heat loss Rubber, plastic gaskets, or plastic strips can all act as a thermal break
heat treatment
a process that can change the properties of the metals.
substrate board
a secondary board material to provide a flat, smooth surface, compatible with membrane installation.(wood fiber or gypsum board)
lead
a soft easily formed long lasting metal that oxidizes over time to a dull white color. not healthy toxic.
Exterior Insulation and Finish System (EIFS)
a stucco-like material applied with fiberglass mesh onto polystyrene rigid foam Layer of plastic foam insulation adhered or mechanically fastened to a backup wall A reinforcing mesh that is applied to the outer surface of the foam A base coat of a stucco like material which embed the mesh An exterior finish coat of a similar stucco like material that is troweled over the base coat
solar reflectance (albedo)
a surface material's ability to reflect sunlight on a scale of 0 to 1. 0 means it absorbs all solar radiation, 1 reflects all radiation.
solid joint seal materials
alternative to gunnable sealants
Glass fiber reinforced concrete (GFRC)
an admixture of short glass fibers furnishes enough tensile strength that no steel reinforcing is required Panel thickness and weight are about one quarter of those for precast They can be molded into variety of shapes with a wide range of colors and textures The panels may be self-stiffened with ribs but the usual practice is to attach a welded frame of light gauge steel studs to the back of each panel only ½" thick so flanges are provided for backer rod and sealant at joints
Galvanic Protection
applying a zinc coating to prevent steel from rusting; forms a self-protecting gray oxide coating, and even if the zinc is scratched through to the steel, the zinc interacts electrochemically to continue to protect the steel
essential elements of a precast concrete cladding panel
attached directly to the building frame Panels are designed to resist lateral forces (wind), gravity loads, and lifting forces Attachment methods must effectively transfer forces to the superstructure Carbon fiber may be used as reinforcement to produce thinner, lighter panels
roof scupper
basically a gutter system components: stripping (layers of felt) sheet metal gutter and down spout
Built up roof membranes (BUR)
bituminous roof membrane made in place from multiple asphalt-impregnated roofing felt bedded in layers of hot bitumen (typically asphalt derived from distilled patrolium) the felt is laminated and applied in overlapping layers (plies) the more plies the more durable the roof almost level or very flat roofs require coal tar to achieve a slope covered with rocks to protect the membrane from sunlight and wear.
Modified bitumen roof membranes
bituminous roof membrane made of factory-manufactured sheets of polymer-modified bitumens. (atactic polypropylene (APP), or Styrene-butadiene-styrene (SBS) used to increase flexibility and toughness. sheets are typically .04 to .160 inches (1-4mm) thick. Reinforced with plastic or glass fibers for greater elasticity and durability installed in plies (two to three) by torch or hot mopped with hot asphalt, or cold applied with adhesive cap sheet is surfaced with mineral granules, thin metallic laminates, or asphalic or elastomeric coatings (white cap sheets comply with cool roofs)
medium-range sealants
butyl rubber or acrylic, have a elongation capacity of plus or minus 5 to 10 percent. used in the building exterior wall for sealing non working joints (joints fastened together mechanically) shrink some during drying
Panelized EIFS Systems
can be constructed in place over a backup of concrete masonry or steel studs
standing water on roofs
can cause deterioration of the membrane
hybrid membrane bituminous roof
combination of Built up roof membranes (BUR) Modified bitumen roof membranes
Parapet/ BUR membrane
components: cant strips, counter flashing, and coping. 45-degree cant strips are frequently used with bituminous membranes to ease sharp bends in the multi-ply membrane.
type 316 stainless
contains higher nickel content and some molybdenum
precast concrete cladding panel
conventionally reinforced and prestressed; utilize high-quality molds and a variety of surface finishes Insulation can be incorporated into the precast concrete panel in a sandwich panel system
surface tension
dealt with by a drip on any underside surface to which water might adhere
momentum
dealt with by a labyrinth
gravity
dealt with through the use of a drip edge
Asphalt or Composition Shingles
die cut from heavy, asphalt impregnated fiberglass or cellulosic felts. Surface mineral granules protect from UV degradation and abrasion. Installed over solid sheathing and underlayment of asphalt-saturated felts or synthetic membranes. Roofing underlayment and shingles (of all types) are generally installed starting from the eaves and working up the slope of the roof, to achieve an overlapping that naturally sheds water off the roof. Moderate fire resistance and last 15-25 years. 12" x 36" account for 90% of roofs in north America.
surface finishes of aluminum
does not corrode because it protects itself with a thin, tenacious oxide film that seals the surface In an exterior environment, the oxide film can develop a chalky, spotty appearance If desired, several finish options are available for aluminum products
light weight insulating concrete
economic. creates nailable roof deck. made with lightweight aggregates or foaming air entrapping agents. applied over steel decking or rough concrete. easily sloped towards drainage. thermal resistance is low for this material, but foam boards can be embedded to improve this. venting is used to allow moisture to escape (top or bottom) *vented metal decking is advisable*
Anodizing
electrically building an oxide coating on some metals, primarily aluminum. color can be added
gaskets
gasket are strips of fully cured elastomeric (rubberlike) materials made in different configuration. seal after being pressed into gap
ballast
holds down and protects insulation in a PMR system. (gravel or crushed rock or concrete)
soft joint
horizontal expansion joint underneath the shelf angle. made wide enough to protect against column creep, brick expansion, spandrel beam deflection, and tolerances while not exceeding the safe movement for the sealant.
roof membrane
impervious sheet of material that keeps water out of the building
Gypsum panel boards
increases fire resistance of the roof assembly
Gauge
indicates the standard thickness of sheet metal for a specific material.
shelf angle
installed on the structural frame to support brick veneer at each floor.
The curtain wall
introduced in late 19th century with the advent of skyscrapers It is an exterior wall supported at each story by a frame and derives its name from the idea that the wall is thin and hangs like a curtain on the structural frame does not bear vertical loads and can be thin and lightweight may be constructed in place or prefabricated of masonry, concrete, metal or glass
Self drilling screws
joins light gauge steel members by drilling their own holes and forming helical threads in the holes as they are installed. plated with cadmium or zinc to resist corrosion
Roof membranes for low slope roofs
life expectancy of 10-30 years depending on material, thickness and exposure to UV radiation and temperature. 3 categories (bituminous, single-ply, fluid applied)
Nonstructural Metal Framing
light gauge steel members used for framing interior partitions and other non-loadbearing applications
Crickets and saddles
locally sloped surfaces used to divert water around obstructions in the roof or create slope in level areas
zinc
long lasting has small amount of copper and titanium to improve work-ability and preserve appearance Less expensive aluminum or steel sheets are factory-coated for greater color choice and improved longevity.
410 stainless
lower chromium and less corrosion resistance. can be heat treated and hardened
304 Stainless Steel (type 18-8)
most common provides adequate corrosion resistance for most applications 18-8 refers to percentages of chromium to nickel
Ethylene Propylene diene monomer (EPDM)
most common thermosetting roof. synthetic rubber that may or may not contain fabric reinforcing. good resistance to ozone, heat, UV radiation and weathering. (typically black but can be cool white).
air pressure
most difficult to deal with dealt with by a pressure equalizing chamber.
roof membrane
must be laid over a smooth and continuous surface (wood roofdecks cannot have holes)
vapor retarders in low sloped roofs
needed more in cold rainy climates with high humidity. dependent on a case by case analysis. materials consist of 1) two layers of asphalt saturated roofing felt bonded together adhered to the upper side of the roof deck or 2) made out of self adhering bituminous membranes air barrier and vapor retarder are generally the same material
clay tiles
old material used for thousands of years. available both glazed and unglazed. heavy, highly resistant to fire and last 30 to 75 years. the alternative is concrete tiles with same patterns available
spray foam insulation
particularly used in residential buildings used by spraying the underside of the roof deck (does not need ventilation)
bright dipping
produces a mirror like appearance
vertical expansion joint
protect the veneer from stresses caused by movements in the horizontal plane
single ply roof membrane
require less on-site labor, more elastic less prone to cracking. more prone to leaking. adhered via ballast or adhesive or fasteners concealed in the seams between sheets.
air barrier
restricts the leakage of air through the roof assembly
green roofs
roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane. Protect membrane from UV degradation Reduce noise transmission Reduce stormwater runoff Provide natural habitat Reduce urban "heat island" effect
skip sheathing
roof sheathing installed in strips with spaces between them to allow the installation of certain roofing materials like wood shingles. allows air to pass through the wood.
openings can be eliminated by
sealing every seam with membranes, sealants, or gaskets. Internal drainage can be provided to move the penetrated water to the outside
curtain all essential elements
shelf angle, soft joint, flashing
rigid insulating materials for low sloped roofs
should be resistant to compression, denting, gouging, moisture decay, and fire, melting when hot asphalt is mopped on it *no single material has all of these virtues* some combo of these (can be combined in some composite board combining these materials is best. materials: Various foam plastics Perlite (expanded volcanic glass) Mineral fibers Cellulose fibers Cellular glass beads adhered to the deck with hot asphalt or adhesives or mechanically with screws *more resistant to wind*
Insulation Coverboard
similar to substrate boards. may be placed over rigid insulation prior to installation of roof membrane. protects insulation board.
Thermoplastic materials
single-ply roofing material. can be softened through heat or solvent welding. seams are strong as sheets themselves. most common: Polyvinyl chloride (PVC), and Thermoplastic polyolefin (TPO) together account for 20% of low sloped roofs
Thermosetting materials (elastomerics)
single-ply roofing material. tight linked molecular structure and cannot be softened by heat. joined by adhesives or tape.
copper
soft metal that turns green in natural air but black in industrial areas. chemical treatments can be used to achieve a desired color
Truss-Supported Stone Cladding
stone is combined into large prefabricated panels by mounting them on steel trusses. each truss is designed to carry wind loads and the dead load of the stone. relatively high $$$
capillary action
the attraction of the surface of a liquid to the surface of a solid. dealt with by capillary break.
dew point temperature
the temperature to which air has to be cooled in order to reach saturation
Thermal Insulation between roof deck (low slope)
traditional method. insulation is between the roof deck and the membrane. Low density rigid boards or lightweight concrete are used. protects the roof deck from temps and is protected by the membrane. (membrane remains exposed) Cons: membrane may leak and cause moister to be trapped in insulation and cause membrane to blister. vapor retarder may be installed below the insulation. Ventilation: top side vents per 1000 Sq feet allow moisture to pass through the exterior. (works best when membrane is not fully adhered to insulation
Track sections
used for top and bottom plates in LGSC. slightly oversize so that studs can fit inside of it and be secure
Preformed cellular tape sealant
used in nonmoving lap joints tape.
Curtain Wall Design and Construction Process
very complex and specialized process It is typically not undertaken by an architect alone Team members usually include the building owner, architect, structural engineer, curtain wall manufacturer, and a cladding consultant The architect and/or cladding consultant typically prepares a set of conceptual drawings and the curtain wall manufacturer prepares a more detailed set of shop drawings complete with installation details
simple Rainscreen cladding
void through which air and moisture are free to move.
Condensation
when a mass is cooled below its dew point, it can no longer contain all its water vapor and some of the vapor turns to liquid
Breather mat
wiry plastic mat which creates a continuous airspace under over which wood shingles and shakes are laid. Prevent accumulation of moisture and accelerated deterioration of shingles
Mechanically galvanized
zinc is fused in a tumbler that contains zinc at room temperature
