I have never tried and install like this though, so I can't say for sure, but I think the spray foam crew's concerns are probably justified here. The heat of the spray foam certainly will soften the baffles at the lease, and the expansion will then have an easier time deforming them. I'm not so sure the spray foam would melt the foam baffles, but I wouldn't be surprised if it caused them to deform, maybe significantly so. No worries about melting or deformation this way, and the materials are readily available and relatively inexpensive. Owens Corning Raft-R-Mate Rigid Extruded Polystyrene Attic Rafter Vent. Roll Form Eaves Vent Roll Out Rafter Tray For pitched roof eaves ventilation On standard pitched roofs where the pitch is 15 degrees or more and the roof void. The 1x2 furring strips create a 1.5" vent gap, the 1/4" waferboard closes off the gap from the interior and gives something for the spray foam crew to spray against. Increases attic ventilation from soffit to attic through thickest part of the. After theyre up, you can snap a line to mark and trim the tails in a nice straight line, to make up for any ridge warp or marking, cutting and fixing errors. For a good straight fascia, add an extra inch or 2 to the tails of all your rafters (total length). It's not super critical though since none of this is carrying any real load. Gable roof framing calculator plan diagram with full dimensions. I find it's easiest to nail at an angle and go through the waferboard, a little of the 1x2, and the rafter. Now use your finish nailer to tack 1/4" waferboard panels up to those 1x2s. Use a finish nailer to tack 1x2s onto the inside edge of each rafter, with one edge tight against the sheathing and the wide side of the 1x2 facing towards the opposite rafter. You could just build baffles with 1x2 furring strips and 1/4" waferboard. I know that I’ll have to create a backer for the spray foam along the eaves and ridge to provide a seal below while allowing air to pass between the soffit vents and ridge vent, but if I can successfully do this, would this idea work? I’d have to protect the soffit and ridge vents and separate them from the foam to maintain venting, but that’s doable.Īs far as I can tell, that would get me the best of both worlds: the roof would stay vented for the purposes of removing moisture, but it would be air sealed to the conditioned space below and with, say, five inches of foam plus another six inches of fiber, I’d have enough R-value. ![]() I’m wondering if I could install rafter vent baffles like you would with fiber insulation in a vented roof assembly, but instead of installing fiber under the baffles, install spray foam. So now I’m left trying to figure out how best to insulate the roof given that it must be vented. ![]() With my current building project (detailed in this thread here), it came to light that the wrong kind of roof underlayment was installed (synthetic instead of asphalt felt), which doesn’t breathe enough to allow moisture to evaporate to the outside and therefore requires a vented roof assembly.
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