Construction Methods and Materials 10 Flashcards

A contractor is installing a masonry veneer wall and discovers the existing substrate framing has a bow of 1.5 inches over a 10-foot span. Under MHIC standards and industry best practices, what is the correct course of action before proceeding with the veneer installation?

Answer: Correct the framing deviation to within 1/4 inch in 10 feet before installing veneer

Masonry veneer requires a substrate within 1/4 inch per 10 feet of plumb before installation begins. Attempting to compensate with thicker mortar joints violates thickness tolerances and can cause structural cracking, water infiltration, and bond failure. Metal furring strips are not a code-compliant solution for bowing in this context, and a homeowner waiver does not override contractor licensing obligations to meet installation standards.

When installing a cold-formed steel (CFS) load-bearing wall stud in a two-story home, a contractor finds the specified 20-gauge stud is not available and substitutes a 25-gauge stud of the same dimension. Which statement best describes the implications of this substitution?

Answer: The 25-gauge stud has significantly lower axial load capacity and the substitution requires engineer approval

In cold-formed steel, gauge numbering is inversely proportional to thickness — a higher gauge number means thinner, lighter steel with less structural capacity. A 25-gauge stud is substantially thinner than a 20-gauge stud and cannot carry equivalent axial loads. Substituting a lighter-gauge member in a load-bearing application without engineer approval is a serious code violation that can result in structural failure and licensing consequences under MHIC.

A licensed MHIC contractor is re-roofing a home and finds the existing roof deck has areas of oriented strand board (OSB) with edge swell exceeding 3/16 inch from prior moisture exposure. The new shingles will be installed over the existing deck. What must the contractor do?

Answer: Replace the affected OSB panels and ensure the new deck is flat within manufacturer tolerances before shingling

Edge swell in OSB creates ridges that telegraph through finished shingles, causing visible waviness, accelerated wear at high spots, and potential cracking of shingle tabs. Shingle manufacturers require a flat, solid, well-secured deck as a condition of warranty. Sanding is not an adequate structural repair for swollen OSB; the panel must be replaced. Foam underlayment does not provide a suitable nailing base and does not correct the underlying defect. Proceeding without repair exposes the contractor to warranty and workmanship liability.

During a bathroom renovation, a contractor installs cement board as a tile substrate in a shower surround and uses standard 1-5/8 inch drywall screws instead of the specified alkali-resistant screws. What is the primary long-term risk of this substitution?

Answer: Standard screws will corrode in the alkaline cement board environment, losing holding power and allowing the substrate to separate from the framing

Cement board has a highly alkaline pH that rapidly corrodes standard steel drywall screws. Over time — often within 1–3 years — the screws lose tensile strength and shear capacity, allowing the substrate to flex away from the framing. This leads to cracked grout, tile delamination, and eventual water infiltration into the wall cavity. Alkali-resistant (typically hot-dipped galvanized or stainless) screws are specified precisely because of this chemical attack mechanism. Screw spacing compliance does not compensate for material incompatibility.

A Maryland MHIC contractor is pouring a concrete footing for a home addition in December when ambient temperatures are forecasted to drop to 28°F overnight. Which cold-weather concrete practice is NOT a code-compliant method to protect fresh concrete from freezing?

Answer: Adding additional water to the mix to increase workability in cold conditions

Adding extra water to concrete in cold weather is expressly prohibited under ACI 306 (Cold Weather Concreting) and violates water-cement ratio requirements critical to strength development. Increasing the w/c ratio reduces compressive strength and durability — the opposite of what cold-weather work demands. Type III cement is a legitimate strategy that increases early heat generation. Heating mix components is a standard ACI 306 approach. Calcium chloride at ≤2% by cement weight is a code-permitted accelerator for non-prestressed concrete. Only excess water addition fails both technical and code scrutiny.

A contractor is framing an exterior wall that will serve as a bearing wall for a second floor. The plans specify doubled 2×10 headers over a 6-foot rough opening. The contractor has 2×10 lumber on site but also has LVL (laminated veneer lumber) members of the same depth. Which statement is most accurate regarding the substitution of LVL for dimensional lumber in this header application?

Answer: LVL substitution requires engineer of record approval and must match the original engineered design values to avoid over-spanning

LVL has higher bending strength (Fb) than dimensional lumber, which might suggest it can span further or be downsized. However, substituting any engineered lumber product for plan-specified dimensional lumber in a structural application requires approval from the engineer of record, because the original header design was calculated using specific material properties, deflection limits, and load paths. Unauthorized substitution — even with a 'stronger' material — can affect connection design, bearing length requirements, and code compliance. LVL is moisture-resistant when properly manufactured and sealed, making answer B incorrect. There is no 4-foot span restriction on LVL use.