All About the Roof

The existing roof is made up of 4x8 rafters, 4 feet on center, with 2x6 tongue and groove decking over. There was zero insulation inside the building envelope, but they had sandwiched several layers of polyiso insulation on top, under the standing seam metal roofing.

Because the new design extends the roof 10 feet north, we saw no reason to copy that construction, especially since the 4x8s were to be hidden by a new ceiling that provided space for even more insulation. The new roof rafters are 11-7/8” I-joists, which alone are not sufficient to get the recommended R-value of R-49 that Climate Zone 5 demands. So, 3 inches of closed cell foam (R-21) are planned, then 9 inches of fiberglass (R-27) with the missing R-1 covered by drywall, sheathing, and such.

The main constraint is that the new roof must plane out on top with the old. (Underneath, they can be underframed to match as necessary.) There was already a hefty wood ridge beam holding up the 20-foot-long existing ridge.

Owens Construction's Bill Owens didn’t want to disturb the old beam in planning for the new 30-foot-long steel beam (weighing in at 850 pounds). So, he and the engineer came up with the idea to slide a new W6x26 I-beam underneath the old ridge and block up to the new addition's roof peak.

Figuring out how to make this happen kept Owens up at nights. Complicating the challenge was that there was not close access to the north end through the pasture, without running the risk of heavy equipment getting bogged down in the mud. The best lift area was the guest parking, a good 100 feet away on the south end of the home.

The solution? Hire a hydraulic, truck-mounted crane for what turned out to be a six-hour “ballet” of lifts—we'll cover this impressive feat in a later post, so stay tuned. “That $2400 I spent on the crane was the best money I ever spent,” says Owens.