Learn how to cover an existing roof with rigid foam,
and prepare for installation of a new roof
with David Joyce
Narrator: Before installing the roof foam, cut back the wall panels to match the roof plane. Like when cutting back the roof overhangs, cutting the foam exactly flush with the wall isn’t that big of a deal. In fact, it’s better to cut off a little too much than too little. If the wall plane is a little proud of the roof plane, it will be difficult to weave the corner.
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Insulation Retrofit Complete
David Joyce: Here we’ve installed two layers onto the wall. We’ve taped all the seams, and we’ve cut it flush with the existing roof. Now we can bring the membrane from the roof down over all of this and either tape it to the Tyvek or tape it to the face of the foil. Capping this will help with the air seal. When we’re done with that, we’ll start with the roof, putting foam on top of the roof. We’ll cut that flush again, maintaining a straight edge because later on we’ll be putting up fascia and soffit. It’s easier to work on a flat surface. We’ll wrap Ice & Water Shield, helping with the air shield in the future. Narrator: Dave’s crew used a regular handsaw to cut the foam in place. The first layer is…