Scissor Roof Truss With Energy Heels

Most standard residential trusses can achieve r values r value referring to a rating that represents the insulation s capacity to resist heat transference from heated to non heated areas and vice versa of 11 or 13 near the sidewall.

Scissor roof truss with energy heels.

This is created by designing the truss with a heel height tall enough to meet the r value requirements. Energy trusses have raised. 347 framing and bracing a truss roof system. 353 framing with scissor trusses.

Energy trusses are designed to allow greater insulation depths at the heel. The option 1 figure to the right shows a raised energy heel. Framing a truss roof system. Because raised heel trusses are high enough to leave the insulation value intact the energy code allows for use of less insulation for the entire ceiling system when raised heel trusses are used.

Another way to achieve the full r value would be by use of insulation with a higher r value per inch at the eaves. Raised heel trusses do not compress the attic insulation over the top plate which compromises the insulation value. A raised heel truss is much like it sounds. The cost of additional insulation is very little and depending on your climate zone and the local energy code you may require less insulation if your.

Even in earlier versions of the irc code min for zone 4c was r38. With this type of energy heel the wall sheathing will usually need to extend up the outside of the truss. 356 framing a skylight well with trusses. The solution for roofs framed with trusses is something called the raised heel truss also called an energy heel truss or energy truss.

The extra height of a raised heel truss roof provides additional space for uncompressed attic insulation and the full depth of insulation to be extended right to the outside of the top plate. To create a truss with an energy heel a vertical member is added over the supporting wall and the bottom chord stops there rather than extending into the overhang. But be sure to see the name i propose below the diagram below comes from a paper by apa the engineered wood association titled raised heel trusses for efficient cost effective comfortable homes. The heel of a conventional plated roof truss where the bottom chord intersects with and bears on the perimeter wall plate and is fitted with a vertical member that literally raises the top chord of the truss.

The costs of insulating at the roof deck compared to at the truss chords is in most cases a much bigger up charge than the cost adder for energy heel trusses.