National Roofing Legal Resource Center

Contract provision addresses inadequate drainage design

When performing reroofing work, roofing contractors should be aware any modification or alteration to a roof's existing drainage system components—including retrofitting drains—could potentially be viewed as altering or designing the drainage system of the roof. Including a provision, such as the one below, in its contract may reduce the likelihood a roofing contractor will be held liable for any damages or losses when a drainage system is not code-compliant.

For example, in a case pending in Alabama federal court, an owner's insurance carrier is alleging a roofing contractor should be liable for a roof collapse caused by water accumulation during a severe storm because during a reroofing project six years prior, the roofing contractor reduced drain capacity 9 percent by installing retrofit drains and crickets between the drains and adding screens to the existing drains to block debris. By performing such work, the reroofing contractor was considered by the insurer's structural engineering expert to have "designed and installed" the facility's roof drainage system, triggering an obligation to do so in compliance with the International Plumbing Code. The insurance carrier is claiming four plumbing code violations embodied in the roofing contractor's work—including failing to recommend or install scuppers or emergency overflow drains in an existing parapet wall— caused the water accumulation. The roofing contractor has argued the work it performed was only the modification or correction of an existing drain system—not the design and installation of a roof drainage system. The reroofing proposal also contained a disclaimer that stated, "We exclude any electrical, plumbing, mechanical or HVAC work."

Importantly, in an interim ruling in the case, the Alabama judge held that whether the roofing contractor was bound to comply with the plumbing code would hinge not on the scope of work it wrote in its proposal but on the work it performed. The court's ruling here shows the importance of having the following two-fold policy for all reroofing projects. It is important a roofing contractor has an open conversation with the customer to explain the importance of having an evaluation of the customer's roof drainage system performed by a mechanical engineer. Also, the roofing contractor should have a strongly worded drainage disclaimer in its contract to put the customer on notice and make it abundantly clear it is the customer's responsibility to consult with an architect or engineer to ensure the proposed reroofing work is code-compliant. Additionally, it may be prudent for reroofing contractors to take the initiative and consult with an architect or mechanical engineer whenever proposed reroofing work involves modifications to existing drainage system elements.

Inadequate Drainage Design: Roofing Contractor shall not be liable for any claims or damages arising from or related to deficiencies in roof drainage. It is the Customer's responsibility prior to commencement of reroofing to retain a licensed architect or mechanical engineer to determine and evaluate the drainage design and compliance with applicable plumbing codes, including potential need for additional drains, scuppers, or overflow drains. Roofing Contractor's work does not include evaluation of code compliance, existing drainage, proper location or size of roof drains, or adequacy of drainage. Roofing Contractor is not responsible for ponding.


NRLRC Home National Roofing Contractors Association