A recent whole-house remodeling project gave me and my crew
the opportunity to use two different techniques for framing
curved walls — one for an exterior wall and one for an
The plans called for a somewhat unconventional exterior curved
bay. Instead of being a curved section of the exterior framing,
the bay was really an applied decorative element, attached to
the outside of the existing flat wall. The bulge was curved on
the outside only; the interior side of the wall stayed
straight. From the inside of the building, the only clues that
the wall was unusual were the deep jambs on the three
The curve was an arc with a 12-foot 8-inch radius that
extended out from the plane of the wall about 10 inches at its
deepest point. The architect thoughtfully designed the curved
bay to be 96 inches long, measured along the arc, allowing it
to be sheathed with full sheets of plywood running
Although we could have framed the curved bulge by attaching
vertical studs of varying depths to the existing sheathed 2x4
wall, I decided to install the new framing horizontally. We cut
curved nailers out of 2x10s and mounted them horizontally on
16-inch centers. This provided great nailing for the
Curved 2x10 nailers, cut on a band saw,
define the exterior radius.
We drew the curves with a string and a pencil, working right
on the subfloor. A jigsaw blade we tried was too light-duty for
the cuts, so we ended up making the curved rips on a band
We first attached 2x4 cleats to the 2x10 nailers, then nailed
the cleats through the sheathing to the studs. We had no
problem bending the 1/2-inch CDX plywood.
Because the curve is gentle, bending
1/2-inch plywood sheathing was easy.
To set off the curved bay from the main plane of the wall, we
installed red cedar shingle siding with a shorter exposure than
the cedar shingles on the rest of the house.
Sheet lead flashing over the window heads conformed easily to
the curved jamb. (Although lead is easy to work with and makes
a durable flashing, it is toxic. After handling lead, be sure
to wash your hands before you reach for a donut.)
The architect proposed roofing the bay with a conical shingled
roof or low-slope copper roofing, but the budget wouldn't allow
it. The rrofing we ended up with -- a low-slope painted board
-- was not ideal.