Performed a wind Mitigation in Florida on a home where there is 15lb felt under shingles. he had a new metal roof put on a couple weeks ago. The roofer put Summit 60 synthetic underlayment on top of the shingles and then put the metal roof panels on top of that. the roofer told the home owner that this would count as SWR and he would get the discount. I do not agree and checked no SWR on the wind mitigation report. From what the FBC says you either need a self adhering modified bitumen attached to the roof deck and joints or an adhesive applied directly to the roof sheathing. No where does it state that a synthetic underlayment applied over shingles would count as an SWR. Am I correct in checking no SWR? Please give your thoughts.
The form is quite clear, self-adhered membrane applied directly to the sheathing.
The roofer is incorrect.
Thank you. That is how I read the FBC.
First the FBC and 1802 form are in direct conflict in this area.
The FBC, uses math, 1, layer, 2 layers, one of those is a primary, the other secondary, under the final roof covering.
Secondary Water Barrier –
A secondary water barrier, consisting of a 4” wide, 40 mil self-adhering polymer modified bitumen
tape, in compliance with ASTM D1970, must be applied directly to all roof sheathing joints, prior to
the installation of the roofing base sheet. As an alternate and only after the base sheet is installed
and approved by the City, an approved “Peel and Stick” self-adhering polymer modified bitumen
cap sheet, or an approved cap sheet applied in a hot-mop application, shall be deemed to meet the requirements for the secondary water barrier.
The form, on the other hand, states either 4 inch strips over every joint or, as most metal roof underlayments are done here in Martin, one layer of peel and stick underlyament applied directly over the wood deck.
My question, how did the roofer comply with the deck re-nailing requirement, without removing the existing shingle roof? And, how is this metal roof attached on a level surface?
That you for the reply. I agree with the nailing. I do not see how a peel and stick and a synthetic underlayment would ever work being applied on top of shingles instead of the original wood roof deck. Thanks