Q+A
Ask the
Building Inspector
Have questions you’d like to ask an expert? We’ll feature a Q+A with various experts and topics each issue. Send your questions to ASK@ HOUSINGFIRSTMN.ORG
with Peter Kulczyk
Q.
As a builder, we are often approached by product manufacturers who want us to use their latest and greatest products, such as new house wraps, foundation anchors, plastic decking, and other components that are intended for residential projects. Do we have any assurance that the local building inspector will approve the use of these products? The answer depends on what information is provided to the building inspector for the plan review. The language in the code is prescriptive in nature as it addresses specific limitations and requirements related to life/safety, structural integrity, weatherresistance, and other considerations, but the code language is not intended to prevent the use of alternative materials, design, and methods of construction, provided that it is approved by the local building inspector (Minnesota Rule, MR1300.0110, Subpart 13). Your inquiry refers to house wraps (aka house sheathing paper), whereas the
code refers to the use of one layer of No. 15 asphalt felt (Type I) or other approved water-resistive barrier (International Residential Code, Section R703.2). If a house wrap is proposed in a project, the permit applicant (typically the builder) should provide available project data that may include the manufacturer’s installation instructions, third-party test data, or a product evaluation report written by an approved agency (evaluation report numbers are generally stamped on the product). This process is very common with house wraps, foundation anchors, and many other components. In response to your inquiry regarding plastic (composite) decking, the code now requires compliance with ASTM D 7032 (International Residential Code, Section R507.2.2), and this information should be made available for the designer, builder, and building inspector as needed.
Q. Many new home designs contain roof girders and multiple-engineered wood beams intended to carry significant roof loads and floor loads. Who is responsible for
determining what is needed for the end support? Generally speaking, the designer is responsible for this determination and ultimately the builder or permit holder. The building code addresses uniform loads for floors, walls, and roofs that are based on repetitive-member conventional framing techniques (three or more studs, joists, or rafters in the same plane) that includes the effects of wind, snow, soil, and earthquakes (International Residential Code, Section R301.1). Span tables in the code also address girder spans and header spans of multiple member solid-sawn lumber and required end support for four common species of wood. The tables in the code are based on the lumber species and grade of the wood (International Residential Code, Section R502.1). This is often referred to as both conventional framing and prescriptive design because of these known values. With that said, the code does not address span tables or bearing requirements for engineered beams (such as laminated veneer lumber, also referred to as LVL lumber; and other composite wood beams), and this also includes engineered floor trusses
JANUARY–MARCH 2022 | HOUSING FIRST MINNESOTA
The Digest
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