Which organization provides the guideline that the maximum distance between an expansion joint and a downspout is 25 feet?

Which organization provides the guideline that the maximum distance between an expansion joint and a downspout is 25 feet?

• A. NRCA
• B. SMACNA
• C. IBC
• D. ASTM

Answer: (B)

The guideline about how far an expansion joint can be from a downspout comes from SMACNA—the Sheet Metal and Air Conditioning Contractors’ National Association. SMACNA publishes detailed standards for architectural sheet metal work, including how expansion joints should interact with drainage components. The 25-foot maximum is set to ensure movement from thermal expansion, contraction, and other roof stresses is accommodated without putting excessive strain on the joint or causing leaks at the connection to the downspout. Staying within this distance helps maintain water control, maintain seal integrity, and reduce the risk of joint failure over time. Other organizations cover related areas but don’t specify this exact spacing. NRCA focuses on general roofing practices and installation, IBC is the building code that may reference standards but doesn’t typically prescribe this specific distance, and ASTM provides material and method standards rather than installation spacing for expansion joints and downspouts.

The guideline about how far an expansion joint can be from a downspout comes from SMACNA—the Sheet Metal and Air Conditioning Contractors’ National Association. SMACNA publishes detailed standards for architectural sheet metal work, including how expansion joints should interact with drainage components. The 25-foot maximum is set to ensure movement from thermal expansion, contraction, and other roof stresses is accommodated without putting excessive strain on the joint or causing leaks at the connection to the downspout. Staying within this distance helps maintain water control, maintain seal integrity, and reduce the risk of joint failure over time.

Other organizations cover related areas but don’t specify this exact spacing. NRCA focuses on general roofing practices and installation, IBC is the building code that may reference standards but doesn’t typically prescribe this specific distance, and ASTM provides material and method standards rather than installation spacing for expansion joints and downspouts.