Our company builds custom homes along Maine's Midcoast. Over
the last few years, this scenic area between Searsport and
Brunswick has become popular with retirees and second-home
One of our current projects is a large beachfront home with two
round towers, each with a conical roof. Trimming out the
exterior of a tower can be slow and tedious, but with thorough
planning, a skilled crew, and a good millwork shop, a job like
this can be manageable and — if the weather is good
Precise roof framing is always important, but it's especially
crucial with a tower, because any inconsistencies with the
framing will create humps or flat spots in the trim. Therefore,
as we set the rafters, we double-checked the overhangs to keep
the variance to within 1/8 inch (see Figure 1).
We used pie-shaped pieces of 1/2-inch fir plywood for the roof
sheathing and covered the whole roof with a layer of Grace Ice
& Water Shield. Roofing felt doesn't stand up for long to
coastal winds, and the lengthy construction on this job made
the self-adhering eaves membrane a good choice for a temporary
Figure 1.Accurate framing is critical for a
good-looking curved trim job. In this case, the rafter tails
lined up to within 1/8 inch, measured from the plate. The
curved plates were built up from four layers of 3/4-inch
plywood, glued and screwed together.
We've found that good staging is critical to making tricky work
like this go smoothly, so when we got to the point of sheathing
the roof, we set up pipe scaffolding. We kept the scaffolding
in place until the tower's cedar shingles were installed and
the trim had a second coat of paint.
The architect's design called for tongue-and-groove beaded fir
soffits arranged in a diagonal pattern. The soffits butt to a
square-edged piece of mahogany, where a decorative knee bracket
would be attached later (Figure 2).
Fitting Straight Windows Into a Curved
Figure 2.The home's original design called for
curved sash, but the custom windows proved too expensive.
Instead, the walls of the tower were framed like an octagon,
but with curved jamb extensions above and curved sills below to
transition from flat to round. Wide pilasters at each corner of
the octagon separate the windows and receive decorative
brackets at the top.
As with the framing, we spent some extra time laying out soffit
bays so that they'd all be exactly the same size. We marked the
inside curve on the first soffit board by holding it in place
and scribing it with a compass. We worked our way out toward
the fascia, blind nailing through the tongue with a trim
nailer. Running the soffit 3/8 inch past the rafter tail
allowed us to slip it into a dado on the back of the curved
fascia (Figure 3). At the last course, we used a 3/8-inch-thick
piece of stock held against the plumb cut on the rafter tails
to scribe a fair curve.
Figure 3.To produce the curved fascia, the crew
first installed the T&G soffit (above), using a flexible
straightedge held against the rafter tails to scribe the radius
on the outer pieces. The soffit was then traced and the exact
curve provided to the millwork shop. The curved fascia (above
right), glued up from strips of Honduras mahogany, was made
with a 1/2-inch-deep dado to accommodate any slight
irregularities in the edge of the soffit. A stepladder allowed
the cut man to reproduce the trim's installed position at the
The next step was to make 1/4-inch-thick plywood templates of
the curved fascia and the curving frieze board that would
circle the top of the tower below the soffit. Using the
soffits, we scribed the 8-foot sheets in place and then sent
them to the millwork shop that supplied the trim, Tidewater
Millwork of Woolwich, Maine.
Tidewater determined the radius from our original templates
and, using 1/4-inch laminations of mahogany, made the fascia
and frieze boards to match. The radius of the decorative crown
applied to the fascia was determined by adding its thickness to
our original templates. For the frieze and other components
with a smaller radius than the fascia, we subtracted the width
of the overhang from the original template.