Glencoe: 21

Question 1

Backfilling:

Answer 1

process of filling in the excavated are around a foundation with soil. This brings the area around the house up to rough grade.

Question 2

Estimate concrete formwork time needed for foundation walls:

Answer 2

Example. Floor plan measures 40’ x26’

1. To determine the total foundation wall area, assume the wall is 8’ high. Multiply 8’ by 132’(perimeter). = 1,056 sq. ft.
2. Assume the wall thickness is 8”. Refer to table on page 273. The table shows the wall will require 7.75 hours per 100 sq. ft. of wall area.
3. Calculate the total time for installing the forms. Since you know it will take 7.75 hours for each 100 sq. ft. Divide the total number of square feet by 100 and multiply by 7.75.
   1,056 sq. ft. / 100 = 10.56
   10.56 x 7.75 = 81.84 hours to install the forms.
4. Next calculate the time needed to remove forms. According to the table, between 3 and 4 hours are needed to remove forms for 100 sq. ft of 8’ wall. Use the larger number as an example.
5. 56 x 3 = 31.68 hours for removing the forms.

Question 3

Estimate concrete material needed for foundation walls.

Answer 3

Example: 8” thick wall with a total area of 1,056 sq. ft.

1. Find the 8” thicnkness in the column at left. Read under material to see 2.47 cu. yds. of concrete are needed for every 100sq. ft. of wall. Therefore you must again divide the total area by 100 find out how many yards of square feet there are.
   1,056 / 100 = 10.56.
2. multiply by 2.47.
   10.56 * 2.47 = 26.08.
   Round to larger 1/4 cu. yard. Thus a total of 26.25 cu yards of concrete are needed.

Question 4

Estimate labor needed for foundation walls.

Answer 4

1. Under “concrete placement” it says that 1 cu yd. takes an average of 3.25 hours
2. Multiply the total cubic yards by the time required to pour 1 cu. yd. This will tell you the total time required. In our example 26.25 cu. yds. of concrete are required. Therefore:
3. 25 * 3.25 = 85.31 hours of labor.

Question 5

Backfilling should be X for safety

Answer 5

as soon as possible

Question 6

Backfilling makes it easier to

Answer 6

transport materials to and from the house.

Question 7

why should a foundation not be backfilled too soon.

Answer 7

The weight of the earth can damage walls that are not yet strong enough to withstand the pressure.

Question 8

During backfilling, the vertical portions of drainpipes X

Answer 8

should be temporarily capped to prevent soil from getting into the drain system.

Question 9

What must be done before backfilling begins:

Answer 9

Foundation drainage,
dampproofing
waterproofing.
under ideal conditions: the floor framing is also in place.

Question 10

Floor framing does what:

Answer 10

braces the tops of the foundation walls.

Question 11

What should be done in cases where walls must be backfilled before floor framing is in place:

Answer 11

walls can be temporarily braced from inside the excavation using framing lumber.

Question 12

Do not use X when choosing backfill material:

Answer 12

materials that expand and drain poorly such as clay or materials that go against best local building practices.

Question 13

How do you layer gravel into excavation:

Answer 13

Layer gravel into the excavation as needed to ensure proper drainage and backfill only 6” to 8” at a time.

Question 14

What do you do to soil in an excavation backfill:

Answer 14

compact it from settling too much later.

Question 15

Do not allow X into backfill.

Answer 15

wood debris, such as lumber scraps and tree limbs into backfill. This encourages insects and uneven settlement when wood debris decompose.

Question 16

What is a CMU

Answer 16

A hollow Concrete masonry unit. Most common type is made with portland cement, fine aggregate, and water.

Question 17

Why are concrete block walls popular?

Answer 17

because CMUs do not require formwork and the blocks are fairly inexpensive. Unlike work of solide concrete foundation, which must be done all at once. Work on a block foundation can start and stop as needed.

Question 18

Full-height foundation walls are often constructed of

Answer 18

eleven courses (rows) of block above the footings, with a 4” solid cap block.

Question 19

One concrete block walls, what does the cap block do?

Answer 19

Seals the cores of the foundation walls.

Question 20

If a block wall must be strengthened:

Answer 20

4 or #7 rebar is placed inside the cores of successive CMUs, then filled with concrete. These should be spaced according to local codes, height of the wall and local soil type.

Question 21

Generally reinforced columns in a 12” thick CMU wall will be spaced no more than X

Answer 21

72” on center.

Question 22

Pilasters:

Answer 22

projections resembling columns that may be used to strengthen a wall under a beam or grider.

Question 23

Pilasters are placed on the X of the wall and are constructed as high as Y

Answer 23

interior side

the bottom of the beam or girder they support.

Question 24

Basement doors and window frames should be

Answer 24

keyed to the foundation for rigidity and prevent air leakage

Question 25

Most widely used CMU sizes:

Answer 25

8”, 10”, 12” nominal dimension.

Question 26

What does the nominal dimension of a CMU allow for?

Answer 26

a standard 3/8” mortar joint

Question 27

Strongest CMU

Answer 27

2 core is stronger than 3 core