Unit 4- Structure Review Quiz #1

Why are rotted sills a problem? *THREE ANSWERS*

1) Rotted sills may be crush and lead to differential settlement 2) Rotted sills often means rotted joists and studs 3) Rotted sills means the house frame is not well anchored to the foundation.

Name four causes of cracks in foundation walls.

1) Shrinkage 2) Differential settling 3) Heaving 4) Horizontal forces

In your own words, describe a cold joint as it relates to a concrete foundation.

A cold joint is formed when a foundation is poured at two separate times. The first part of the foundation has started to cure when the second part is poured. At the intersection, a cold joint is created.

What is the difference between a pilaster and a pier?

A pilaster is a thickening of a foundation wall to accommodate the concentrated load of a beam or a column. A pier is a stand-alone structural member that can be thought of as a column sunk into the ground.

Which is stronger? A) a poured concrete wall B) a concrete block wall of the same dimension

A poured concrete wall.

What is the difference between a strip footing and a pad footing, and where would each be used?

A strip footing or spread footing is used under a foundation wall. A pad footing is used under a column. Pad footings distribute concentrated loads. Strip footings handle more evenly distributed loads.

All of these may be floor functions, EXCEPT: a) transferring live and dead loads to the foundation b) providing lateral support for foundational walls c) carrying the weight of masonry chimneys

C- carrying the weight of masonry chimneys

List the three common foundation configurations and footing types.

Common foundation configurations include basements, crawl spaces, and slab-on-grade. Common foundation types include spread footings, pad footings, piles, and piers.

In general, which crack would be more serious? A crack that has moved in one plane or a crack that has moved in two different planes?

Cracks in more than one plane.

TURE or FALSE: Cracks due to horizontal forces rarely result in a structural problem.

False

What is the function of a footing? A foundation?

Footings transfer the live and dead loads of the building to the soil over a large enough area so that neither the soil nor the building will move. In areas where frost occurs, footings prevent frost from moving the building. Foundations transfer loads from the building to the footings. Foundations may also act as a retaining wall, resisting lateral soil pressure, for example.

There are several different materials that a foundation might be made of. List as many as you can.

Foundation materials include concrete, concrete block, cinder block, brick, clay tile, stone, and wood.

Explain the difference between uniform settlement and differential settlements.

In uniform settlement, the entire house moves and no cracking develops. With differential settlement, one part of the house moves relative to another. This typically results in cracking.

Why might a damaged foundation wall start to move suddenly after a heavy rain?

Increase in hydrostatic pressure, or swelling of expansive soils.

In your own words, define lateral support as it applies to foundations.

Lateral support is usually a floor system secured to the top of a foundation wall, preventing it from tipping inward.

Explain the difference between a live load and a dead load. Give examples.

Live loads, such as people, wind, and snow, vary. Dead loads, such as the building materials, are relatively fixed.

It is a good idea to inspect the neighborhood as you are arriving at an inspection. What kinds of things should you look for and how can they help you in your inspection?

Look for structural problems in other homes in the neighborhood. Check the general topography. Houses on side-hill lots may be subject to cut and-fill-type settlement problems. Houses near the bottom of slopes may experience flooding problems. The general age of the neighborhood is useful information. Older neighborhoods provide a more reliable test of time. You also may know about specific problems such as expansive or weak soils, high water tables, underground streams, or reclaimed land.

If you identify a foundation crack, is it possible to determine the rate of movement at the time of the inspection?

No.

When a foundation is supported on piles, are the piles typically visible for inspection?

No.

Describe a typical shrinkage crack.

Shrinkage cracks are rarely more than 1/8 inch wide and typically do not involve displacement of the concrete on either side of the crack. Shrinkage cracks usually show up within the first year of life in the home. Shrinkage cracks do not extend through the footings or up into the structure above. Shrinkage cracks may occur at stress concentration points such as window openings.

What is a shrinkage crack and what causes it?

Shrinkage cracks are typically caused by natural curing of concrete.

List FIVE structural components of floors, as defined in this unit.

Sills Columns Beams Joists Subfloors

TRUE or FALSE: Floors will bend a little before they break.

TRUE

What is the main implication of a shrinkage crack?

The implications of shrinkage cracks may be leakage, but not structural problems.

Often horizontal forces will cause horizontal cracks in a foundational wall. Why might the crack disappear near the edge of the wall?

The perpendicular wall reinforces the cracked wall near the end, preventing it from moving.

Why is wood contact with concrete near or below grade level discouraged?

To avoid moisture and possible rot

What is the main function of sills?

To connect the top of the foundation to the wood floor system

It is sometimes difficult to distinguish between a settlement problem and a heaving problem. Give a few examples of how you would distinguish between the two.

To differentiate between settlement and heaving, check whether cracks are opening-, crushing-, or sliding-type cracks. If sidewalks, driveways, and patios slope down toward the house, settlement is more likely. If they slope up towards the house, heaving is more likely. If there is hump in the central part of the house but the columns are not cracked or displaced, the house perimeter is probably settling. If central columns show lots of cracks in the floor area and the floor slopes up toward the column, heaving is more likely. Are overhead electric wires at a different angle than neighboring houses? Is the house higher or lower? Check adjacent houses for similar evidence and neighborhood trends. Look at the soil line against the building. If the front door sill is below grade level, settling is more likely. If you can see a dirt line 6 inches above the existing grade, heaving is more likely.

The foundation should extend far enough out of the ground that the wood members are not below grade. Explain why.

Wood members are prone to rot if they are at or below grade level.

Why is it critical to document how the crawlspace was inspected?

Your client has to understand the limitations of your inspection. Crawl spaces can be troublesome. If you couldn't get a good look, your client should understand that there is a greater risk of unforeseen problems.