MRS Building Materials & Mold Growth 2

Question 1

Which property of oriented strand board (OSB) makes it more susceptible to mold than plywood?

Accepted Answer

Greater moisture absorption due to exposed wood strands

Answer

OSB absorbs moisture more readily than plywood because the exposed wood strands on its surface and edges wick water, providing ideal conditions for mold colonization.

Question 2

What is the approximate minimum equilibrium moisture content at which most mold species can begin colonizing wood framing?

Accepted Answer

19%

Answer

Wood framing at or above 19% moisture content provides sufficient water activity for most mold species to begin active colonization and growth.

Question 3

Which building material component is the PRIMARY food source for mold growing on painted drywall?

Accepted Answer

The paper facing of the gypsum board

Answer

The paper facing on gypsum board contains cellulose, which mold readily digests, while the gypsum core itself provides little organic nutrition for mold growth.

Question 4

A remediation specialist finds mold on concrete block walls. What is the most likely reason concrete supports mold growth?

Accepted Answer

Dust, dirt, and organic debris deposited on the surface provide nutrients

Answer

Concrete is inorganic and not itself a food source, but dust and organic debris that accumulate on concrete surfaces supply the nutrients mold needs to colonize.

Question 5

Which type of insulation is considered LEAST susceptible to mold growth?

Accepted Answer

Spray polyurethane foam (closed-cell)

Answer

Closed-cell spray polyurethane foam is both inorganic and impermeable to moisture, making it highly resistant to mold colonization compared to fiber-based insulations.

(MRS) Mold Remediation Specialist Practice Test

(MRS) Mold Remediation Specialist Practice Test

MRS Building Materials & Mold Growth 2