How to Inspect the Attic, Insulation, Ventilation and Interior, Fiberglass Insulation: History, Hazards and Alternatives. Also, check to be sure that you are in compliance with the manufacturer warranties when installing shingles over an unvented roof in all climates. The AccuVent soffit insulation baffle is made of rigid recycled plastic. Seal and insulate leaking roof ducts with caulk. Proper ventilation in the work area should exist during application. Rafter vents ensure the soffit vents are clear and there is a channel for outside air to move into the attic at the soffits and out through the gable or ridge vent. If any of these issues are of concern, there is another option. Cut 1-in.-thick rigid polyiso insulation into 2-in.- wide spacer strips, and glue them to the inside face of each rafter with a spray-foam adhesive like Pur Stick (www.todol.com). March 27, 2017 . All of our manufacturing facilities, distribution centers, technical and customer service locations continue to … A complete resource that includes the best materials and the right techniques to build a sturdy, leak-free, attractive roof on any house. You can only hope you’re doing a good-enough job. It almost looks as if someone sprayed open or closed so insulating foam along a metal roof ridge vent. If the attic space is going to be conditioned, either for living or mechanical purposes, or if a home design calls for a vaulted ceiling, provision R806.3 in the International Residential Code calls for the roof deck above the space to be vented continuously from the eave to the ridge. Low-density, open-cell foam is permissible, but in climate zones 5 and above, it has to be covered with a vapor-retarder coating, like rigid foam or painted drywall. 8 ft. No interior Class I vapor retarders (e.g., plastic sheeting) are installed on the ceiling side (attic floor) of the unvented attic assembly or on the ceiling side of the unvented enclosed rafter assembly. After all, the shingle color and the roof orientation are much more significant concerns when it comes to shingle life. air space under the sheathing for ventilation, 2 in. Hunter Cool-Vent Cool-Vent is a venting composite insulation board that consists of a 4'x8' panel of rigid polyiso, a middle layer of solid wood spacers, creating a standard 1" air space and a top layer of APA/TECO rated OSB or plywood. Attic space can be used for storage, but only if you build an elevated platform above the insulation. Condensation control is most often accomplished by installing rigid foam above the roof deck or by installing air-impermeable spray-foam insulation directly against the underside of the roof deck. It works absolutely everywhere—when executed properly. In cold climates, snow can enter the soffit and ridge vents, melt, and potentially cause rot. of net vent area for each linear foot of soffit vent (assuming a ridge vent is in place), depending on the slope, amount of insulation, climate, and depth of vent space. How does one vent a lower roof that has no ridge? Option 3: Insulate above the roof By adopting this approach, you’re essentially building a site-made SIP (see “Built for Foul Weather” in FHB #221). I’ll also explain when it makes sense to move the thermal, moisture, and air-control layers to the roof plane, and how to detail vented and unvented roofs correctly. Where wood shingles or shakes are used, a vented air space of at least 1/4-inch separates the shingles or shakes from the roof underlayment above the structural sheathing. Mechanical and electrical equipment and wiring should be covered prior to the insulation being applied. The success of a vented attic or roof deck relies on its airtightness. and provides certification to help you stand out from the crowd. This is easy to accomplish in simply constructed roofs and difficult, if not impossible, to accomplish in roofs that have hips, valleys, dormers, or skylights that interrupt the rafter bays. The code calls for a minimum of 1 in. Unfortunately, we manage to screw it up again and again, and a poorly constructed attic or roof assembly can lead to excessive energy losses, ice dams, mold, rot, and lots of unnecessary homeowner angst. It’s more durable than other foam-based products and installs quickly with staples. Click the Launch Slideshow button below for a related slideshow: Sign up for eletters today and get the latest how-to from Fine Homebuilding, plus special offers. Researchers who have studied cathedral ceiling ventilation recommend 10-20 sq. This illustration shows a sloped roof with cavity spray-foam insulation sprayed on the underside of the roof deck and covered with sprayed-on thermal or ignition-barrier coating. Similarly, not everyone can afford to spray nearly 10 in. A vented attic works in hot climates, mixed climates, and cold climates. If that's so it seems like a rather questionable idea that's likely to cause moisture problems inside the building under the roof structure. For a cost effective quality foam roof recoat, we recommend UltraShield acrylic elastomeric roof coating. chute or baffle. On 2019-02-27 by Pretty Mhlongo. They don’t follow the rules. Don’t think you can get away with putting ductwork in an unconditioned attic just because you sealed and insulated it. In hurricane-prone zones with frequent high-wind events, vented-soffit collapse can pressurize a building, which can cause windows to blow out and the roof to be blown off. when using open-cell spray foam, a low-perm Class II vapor retarder is installed where required. It’s also easier and often less expensive to pile on fiberglass or cellulose insulation at the attic floor to hit target R-values than it is to achieve a comparable R-value in the roof plane. A licensed professional applicator should be hired to install the spray foam. Metal roof costs are typically around the same as asphalt roofs. When open-cell spray foam is used, a low-perm Class II vapor retarder is installed where required. In most climates, builders have to insulate the roof sheathing to prevent condensation from occurring within the assembly. The approach also remedies thermal-bridging issues. Start your subscription today and save up to 52%. 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