Raised Heel Attic Truss Design

Standard truss figure 2.

Raised heel attic truss design.

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. A raised heel truss is identical to a conventional truss except for one difference. According to the 2012 international residential code for seismic zones or zones designated for winds of 100 mph raised heel trusses more than 15 25 have to be blocked and braced. The cost of additional insulation is very little and depending on your climate zone.

Basic wind speeds of 110 mph or less ultimate design wind speed vult of 140 mph or less. Raised heel trusses for efficient cost effective comfortable homes form r330 provides guidance on building with raised heel trusses for designs that meet these categories. While this article focuses on configurations we also have a very cool set of illustrations showcasing the different parts anatomy of roof trusses. Design a raised heel.

It is raised higher with a heel that extends up from the top of the wall and elevates the truss at the building s edges. The top of the top chord is 20 above our top plate. Just as there are many types of roofs with many roof parts there are many different types of roof trusses this extensive article explains through a series of custom truss diagrams the different truss configurations you can use for various roofs. The guide can be downloaded for free from the apa s website.

Use of wood structural panels for energy heel trusses. The option 1 figure to the right shows a raised energy heel. Raised heel truss truss heel height the vertical depth of the truss at the outside face of the bearing. If prompted that the layer framing roof trusses is not displayed click yes to turn on the display of this layer in the current view.

It greatly simplifies attic ventilation and it leaves ample room for insulation. Raised heel trusses 9 1 4 to 15 1 4 inches in depth for other wind or seismic categories or raised heel truss depths consult the irc ibc or apa system report sr 103. Also the raised heel trusses are assumed to have a heel height of between 9 inches to 15 inches. On the general panel of the roof truss.

Using the select objects tool select the roof truss and then use the open object edit button. Standard heel typical truss heel height is about 4. Raising the truss higher has two big advantages. This is created by designing the truss with a heel height tall enough to meet the r value requirements.

To build the energy heel truss click build framing roof truss from the menu. With this type of energy heel the wall sheathing will usually need to extend up the outside of the truss. We installed raised heel trusses with bottom chord overhangs on our house. Raised energy heel typical truss heel height is about 12 but may be designed to most any height per the building designer specification.