![]() This would not be a good solution in a cold climate, where you would have to insulate against conductive heat losses from inside the building. The space should be ventilated with continuous soffit and ridge vents. The roof would then have about the same insulating value as R-11 fiberglass against downward heat flow. Rafter ties (or ceiling joists acting as rafter ties) are required by code unless the house is designed so that the walls or a structural ridge beam carries the full load of the roof. Use either two layers of reflective foil insulation installed back to back, or one layer of a "double-polished" reflective material, which is shiny on both surfaces. This would prevent the building from absorbing a significant amount of heat, providing the radiant barrier has at least a 1/2-inch air space on either side. In warm climates, a second possibility is to install a new roof deck on 2x2 sleepers over the existing sheathing, with a radiant barrier between the old and new roof decks. The first method is to install a urethane foam insulation board and a new plywood deck over the existing sheathing (see illustration). Cathedral ceilings are popular in many homes, but they have special issues with the downward load on the rafters that push outward on the exterior walls. There are two ways to handle the insulation problem. Fiber-cement shingles weigh just a little more than architectural-grade asphalt shingles (approximately 400 pounds per square when installed). These are becoming more widely available and seem to provide a long-lasting roof without adding much weight. If the framing won’t support the weight of concrete tile, my choice of roofing in a hot climate would be fiber-cement shingles. What is the best roofing and insulation to use on a 20-year-old house with exposed rafter cathedral ceilings? The framing doesn’t seem strong enough for tile, which is common here in the Southwest, and the roof needs substantial insulation to shield against an extremely hot summer climate.Ī. Collar ties, contrary to popular belief, do not prevent walls from spreading.Q.Where they are required, they should be installed on every other rafter where rafters are on 24-inch centers. ![]() Collar ties are probably not needed if approved metal connectors were used to fasten the rafters to the ridge.InterNACHI inspectors should not call out a lack of collar ties as a defect unless they know that collar ties were required in the jurisdiction where the home is located at the time the home was built. interior design to exterior structure, such as the natural stone wall linings and open ceiling with decorative rafters. By leaving it open, we not only have the actual. They may or may not be required, depending on the jurisdiction. While it might not seem like much, adding drywall would lower the lowest point of the ceiling about an inch.In high-wind areas, uplift can tear a roof off of a house if it's not properly attached.Ĭollar ties and ridge straps should be installed on roof with a minimum slope of 3:12, a maximum wind speed of 100 miles per hour, and a maximum roof span of 36 feet. Install 1/2' thick gypsum board over the rigid insulation, with possible nailing surfacefor gypsum board which would give me another air space 3. They must be spaced no more than 4 feet (1219 mm) apart. Open rafter garages are popular because they are inexpensive, and the resulting roofs are also remarkably durable and resilient. install 2' thick or 2 x 2' thick rigid foam insulation, with a 3/4' air space between the deck material between the roof rafters. They must be at least 1 inch by 4 inches (25 mm by 102 mm). If collar ties or ridge straps are installed to connect opposing rafters, they must be located in the upper third of the attic space. (Image credit: The Stone & Ceramic Warehouse. Ridge straps are permitted to replace collar ties. A collar tie is a tension tie in the upper third of opposing gable rafters that is intended to resist rafter separation from the ridge beam during periods of unbalanced loads, such as that caused by wind uplift, or unbalanced roof loads from snow.
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