CRC Foundation & Structural Systems

Question 1

According to the IRC, what is the minimum footing width for a one-story wood-frame structure built on soil with a load-bearing capacity of 1,500 psf?

Accepted Answer

12 inches

Answer

IRC Table R403.1 specifies a minimum footing width of 12 inches for a one-story structure on soil with a 1,500 psf bearing capacity.

Question 2

What is the primary purpose of installing a vapor barrier beneath a concrete slab-on-grade in residential construction?

Accepted Answer

To reduce moisture migration from the soil up into the slab

Answer

A vapor barrier (retarder) prevents soil moisture from wicking upward through capillary action into the concrete slab and living spaces above.

Question 3

Per the IRC, what is the minimum concrete compressive strength (f'c) required for a residential garage floor slab?

Accepted Answer

3,500 psi

Answer

IRC Table R402.2 requires a minimum f'c of 3,500 psi for garage floor slabs and other concrete exposed to freezing, thawing, or deicers.

Question 4

What is the primary structural function of anchor bolts installed in a residential concrete foundation?

Accepted Answer

To mechanically connect the sill plate to the foundation wall

Answer

Anchor bolts fasten the wood sill plate to the concrete or masonry foundation, transferring lateral forces (wind, seismic) from the structure to the foundation.

Question 5

Which foundation type is most appropriate when constructing a residential structure on significantly sloped terrain to maintain required frost-depth embedment?

Accepted Answer

Stepped footings that follow the grade change

Answer

Stepped footings allow the footing depth to remain constant relative to the slope while maintaining required frost-depth embedment at each level.

(CRC) Certified Residential Contractor Practice Test

(CRC) Certified Residential Contractor Practice Test

CRC Foundation & Structural Systems