All about Roof Trusses
A Common Residential roof
truss is made up of 5 parts.
1. The Roof
Rafter on which roof sheathing and finally roof surface is attached
2. The
ceiling rafter on which the ceiling surface is attached
3. Bracing tying
the two elements together into geometric supporting structure.
4. The Truss
Tail which is the extended portion of the roof rafter protruding past the wall
creating an overhang.
5. Connection
plates which are steel plates with barbs punched one way through the plate,
creating a connection of two members when this plate is forced by machine into
the surface of the two members.
Since local
energy code requires about 12” of insulation in our area (using batt style) to meet the minimum
R-38 requirement we have to examine how different kinds of trusses affect this
ability to insulate (mainly over the wall where the two members meet). Ever see
ice dams on the eaves of houses? The
Economy truss is the main cause.
Common Residential Truss
types (3) shown
Left: Economy Truss (poor): has the minimum amount of wood required to attach the two members
Center: Max Butt Truss (better): Raised heel gives more height for insulation
Right: Energy Truss (best):Raised heel gives full height for insulation
Note: raised heel trusses are more expensive.
Left: Economy Truss (poor): has the minimum amount of wood required to attach the two members
Center: Max Butt Truss (better): Raised heel gives more height for insulation
Right: Energy Truss (best):Raised heel gives full height for insulation
Note: raised heel trusses are more expensive.
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