CREATING EXTERIOR SOFFITS

In the dry Southwest, open, exposed rafter tails are preferred. But elsewhere—especially in cold, wet locations—soffits are more popular. Eave soffits are usually vented.

There are quite a few ways to frame soffits. The easiest way is to have the truss company extend the joist chord beyond the building line to form a level overhang. This is called a raised-heel truss.

If the trusses do not have a raised heel, you can still build a sof­fit easily by sheathing the underside of the sloped rafter tails. For a level soffit, nail a long 2x to the building and sheath between it and the gutter board or subfascia. If only a fascia board is used, cut a groove near the bottom edge to support the outer edge of the soffit board. No matter which type of fascia treatment you choose, make sure you install fire-stops between the studs to help prevent a fire in the wall from spreading into the soffit area. Check with your building department to find out which fire-stop details are required.

exterior walls and mark the entire length of the building at 2 ft., 4 ft., 6 ft., and so on, putting an “X” on the far side of each mark. Do the same on any long interior walls that run parallel to the outside walls. Mark the same 2-ft. o. c. layout on several straight 16-ft. 1×4 boards. These 1xs will later be nailed near the ridge to hold each truss upright at the proper spacing. Despite your best efforts to line the walls (as explained in Chapter 4), the exterior eave wall plates may not be totally straight. If you hold the truss overhang to a wall that is not straight, the rafter ends and fascia won’t be straight, either. There is an easy way to remedy this. Measure 1 in. in from the outside at each end of the exterior wall’s top plate. Snap a chalkline the full length of the wall to create a straight reference line. Make an alignment mark on the joist chord of each truss. Measure in from the end of the truss the planned eave overhang distance plus 1 in. When install­ing each truss, put the truss mark right on the plate’s snapped reference line. As long as the truss fabricators cut all the tails the same length, the truss ends will be aligned.
WITH A RAISED-HEEL TRUSS
-Roof sheathing	With a raised-heel truss, th e joist chords provide the framing for the eave soffit.
Rafter chord
Fascia Soffit vent
Joist chord Exterior wall —
Soffit sheathing
Wall sheathing WITHOUT A RAISED-HEEL TRUSS
Subfascia
A groove in the fasciai supports soffit board.
2x — nailer
Fire-stop