Roof Truss Soffit Detail

The design of your eave is dictated by the construction of your roof.

Roof truss soffit detail.

This is only a problem in the corners of the roof. For example 4 12 pitch means 4 inches of rise in 12 inches of run. The last pieces to go in were nailing blocks above the ledger for the back of the return and at the bottom edge of the soffit for attaching the rake 20. The vertical rise of the top chord per 12 horizontal inches is the roof pitch or slope.

This 26 span truss with a 4 12 roof pitch is the most economical truss we can build. The lookouts are fine but block the airflow from the soffits see diagram 2. Before the roof sheathing goes on the open framing provides easy access for attaching the return blocking and the nailers for the rake soffit. If we go any larger it will require more webbing inside the truss which will directly affect the cost of the truss.

Then the roof sheathing gets attached and extends over the sub fascia. Cad details document name pdf dwg download all cad construction details 37 1 mb 3 4 mb mc01 identification of roof areas 694 kb 167 kb mc01a single layer underlayment 678 kb 302 kb mc01b double layer underlayment 711 kb 322 kb mc02 vent pipe flashing 626 kb 349 kb mc03 valley. Then the thinner fascia is attached to the sub fascia. To support the wide overhangs the trusses have lookouts see diagram 1.

A gable roof has a cornice along the side walls formed at the rafter ends. Soffits are actually part of the cornice or eave the point where the roof projection and the side walls of the building meet. Steeper roof pitches require longer webs which add to the cost. The sub fascia is usually a 2x6 that is ripped so that the blocking framing for the soffit 6 can fit underneath and tie into the notch in the fascia.

The pitch of the roof also affects the height of the sub fascia. We have some fairly standard raised heel roof trusses soffit ridge peak venting and 2 foot overhangs at the eaves and gable ends. R7 roof eave and soffit detail r8 rafter and joist bridging r9 collar tie at rafter detail r10 rafter brace connection detail r11 roof framing with wood tail extension r12 wood truss bearing on steel wall r13 collector block detail r14 non aligned roof wall framing r15 hip beam. Trusses streamline construction but it s important when using them to make sure the resulting eave works with the design of your building.

The same is true if we make it steeper. The steeper the roof the more expensive the trusses get because the longer the boards get and the more roof area increases.