RN has various meanings in the Chemistry category. Discover the full forms, definitions, and usage contexts of RN in Chemistry.
Lumber used to support the roof sheeting and roof loads. Generally, 2 X 10's and 2 X 12's are used. The rafters of a flat roof are sometimes called roof joists. A naturally-occurring, heavier than air, radioactive gas common in many parts of the country. Radon gas exposure is associated with lung cancer. Mitigation measures may involve crawl space and basement venting and various forms of vapor barriers.
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