Alpine

39 engineering from the truss manufacturer. Non-structural members, such as overhangs or filler bottom chords may be cut as long as they do not interfere with the structural integrity of the truss. What is temporary bracing? CV: Temporary bracing is described as bracing in TPI's BCSI 1-02 as bracing which is installed to hold the trusses true to line, dimensions, and plumb. In addition, temporary bracing holds the trusses in a stable condition until permanent truss bracing and other permanent components such as roof or floor sheathing, joists, or purlins which contribute to the overall rigidity of the roof or floor are in place. What is permanent bracing? CV: Permanent bracing is bracing that will be installed in the roof system as a permanent part of the roof system. The most common is continuous lateral bracing which is a member placed and connected at right angles to a chord or web to prevent buckling under loads less than design loads. Other examples are T-braces, L-braces, etc. What are energy heels? CV: An energy heel is a truss with a raised heel to allow for proper ventilation with increased insulation at the wall line. A simple energy truss is one where the top of the bottom chord just touches the bottom of the top chord, with a wedge plated on. This provides a raised heel of about 7-8 inches, depending on the pitch. This is the cheapest way to go. A standard energy truss will typically have a set heel height, such as 8 or 10 inches. Typically, the end condition is made with a slider or a snubbed wedge. A 12" energy heel provides for the most insulation and air flow. This is a good choice for scissors trusses so that a good amount of insulation can be applied; and, at the same time, plenty of room is available for air flow. The most important issue, of course, is providing the proper air flow (ventilation) so that condensation is minimized. When the temperature difference between the insulation space and the attic is large, the potential for condensation is great. Wet insulation loses its "R" value. It is imperative that attics be well ventilated. Typically, a baffle of cardboard or plastic is stapled to the sheathing between the trusses to allow a clear path for air to flow. The baffle extends a little beyond the wall line past the point where the insulation stops. On the inside, it extends along the pitch so that the outlet is above the insulation layer. One thing that helps the condensation problem is a moisture barrier on the ceiling. This prevents the warm, moist air from escaping into the attic. SIMPLE STANDARD 12" ENERGY HEELS

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