Larsen Truss Roof

A larsen truss is a system of adding large amounts of insulation to a house by putting light weight trusses around the perimeter separate from the structural parts of the building.

Larsen truss roof.

I joists on a roof. A larsen truss is a lightweight wall extension used to create additional wall space to hold insulation. Modified larsen truss retrofit. In most cases conventional 2x4 studs hold up the roof load and the 2x4s are sheathed with plywood or osb.

When i arrived much of the roof had been framed but i was able to climb up for a little valley framing. Ladder like trusses are installed around the exterior of the building in my case the frame and drywall sheathed and filled with insulation. A new roof was framed on top of the existing roof deck which was air sealed with high performance tape. These lightweight trusses are tacked onto the sheathing after a house is framed and sheathed.

My modified larsen truss system requires conventional platform framing of the first floor walls second floor deck and then eastern balloon framing of the second floor bearing walls let in ledgers to support ceiling joists and rafters. Some builders argue that a proper larsen truss must be added onto the load bearing wall sheathing to be truly a larsen truss and not attached directly to the load bearing wall. Larsen trusses are non structural.