I run a specialty millwork shop in Narragansett, R.I. For
several years I've been working with a local custom builder,
David Baud, to produce major components for the high-end homes
he builds. Typically, these are relatively complicated pieces
of the building that would ordinarily be built on site but
require extensive layout, complicated scaffolding setups, and
lots of crew. Tackling these tasks off site in the shop
simplifies and speeds the entire process. The advantages are
numerous — including no weather delays and close control
over scheduling and quality — and have proven themselves
on job after job. Now, whenever we sit down to bid a set of
plans, one of the first things we do is to circle every element
that might lend itself to off-site fabrication.
In this article, I'll describe how we completed a decorative
timber-rafter roof overhang for a new home on the coast of
Rhode Island. The house was designed to look like a converted
barn. Though it was stick-framed, it contained various
timber-frame components both inside and out. The eaves details
I worked on create the impression of heavy timber rafters, but
in fact the roof was conventionally framed with 2x12 rafters on
You'll probably never replicate the exact details shown here.
Still, this method could be easily adapted to most any type of
decorative rafter tails.
The false rafter tails actually start at the frieze board,
which we used as a kind of mounting plate (see Figure 1). The
framers stopped the actual 2x12 rafters flush with the plate,
minus 11/2 inches to accommodate a 2x8 band, or subfascia. They
ran the wall sheathing up over the band, leaving it about 2
inches short of the rafter tops to provide roof
False rafter tails give the impression of
a timber-framed roof structure. First, the tails were attached
to the frieze board; then the entire assembly was secured to
the frame with a space left for roof ventilation. The bottom
course of plywood roof sheathing ties the overhang to the
When they sheathed the roof, they held the bottom course of
plywood up a couple of feet from the ends of the 2x12 rafters.
That way, after the overhang assembly was fastened in place,
the bottom course of plywood provided a strong lap, securely
tying the tails back to the roof diaphragm.
There were two different overhang details on the project shown
here. The eaves of the main roof have 22-inch-long shaped
tails, while the overhang at the entry and garage has
3-foot-long tails that rest on a beam supported by large
structural knee brackets.
Ideally, I would have used solid cedar stock throughout for its
exceptional stability, decay resistance, and paintability. But,
except for the frieze and rake boards, cedar didn't fit in the
budget, so we ordered green 6x8 #1 Douglas fir instead,
specifying no heartwood for best stability.
Because the wood was green, we had to take measures to minimize
twisting and checking, and to accommodate shrinkage as it
dried. One of the great advantages of doing this work in the
shop, out of direct sunlight, is that it protects against rapid
moisture loss and the resultant checking you'd get if you were
out in the field. Once the tails were installed, they were
further protected by the shade of the overhanging roof,
allowing the wood to more slowly acclimatize.
The overhang assemblies also included frieze and rake boards;
for these we used clear vertical-grain 5/4 western red
While the shorter tails were small enough to be cut out on the
band saw, the larger ones, plus the various mortises and
tenons, required lots of router work. We use top-bearing (or
bearing-over) and bottom-bearing (or bearing-under) pattern
bits, depending on what we're cutting.
For example, after epoxying 22-inch tails to the rake boards, I
used a bearing-under bit that followed the tail's contours to
remove the waste from the rake board (Figure 2). This creates
the impression that the entire rake board is a full timber
Figure 2.Following the shape of the band-sawn
rafter tail, the author used a bottom-bearing bit (top right)
to profile the end of the attached rake frieze (top left),
which was glued to the tail with two-part epoxy. Once in place,
the rake board looks like a full-dimension timber rafter
Figure 3.Top-bearing bits came in handy for
following plywood and MDF templates — for cutting
mortises (top), for shaping a tenon on the end of a rafter tail
(bottom left), and for routing an angled pocket (bottom
To cut profiles on the long tails or the stub tenons on the
back ends of the tails, I used a bearing-over bit that followed
a 1/2-inch-thick MDF template tacked to the fir stock.
Templates ensure that every piece is uniformly identical
Occasionally I'll make a saddle jig, which is two identical
templates separated by a piece of stock equal to the thickness
of the beam I'll be cutting. I slip the jig over the end of a
beam and tack or clamp it in place; then I rout one side, flip
the beam, and finish the cut on the opposite side without
touching the template (Figure 4).
Figure 4.Two-sided "saddle" templates allowed the
author to work from both sides of thick stock to cut a tenon
using a top-bearing bit.
If you have to make repetitive profiles on thicker stock,
making a saddle jig is well worth the effort.
Some Site Assembly Required
We sent the shorter rafter tails to the site loose, along with
the frieze board. We figured it would be easier and more
accurate for the site crew to lay out the exact spacing.
Each of the 22-inch-long tails had a stub tenon on the end,
which would fit snugly into a matching mortise cut into the
frieze board on site. We provided the framers with the
necessary router template for cutting these recesses.
Although the tails could have been recessed at their full
dimension into the frieze, the stub tenon — a standard
joint in timber framing — allows for wood shrinkage
without a gap showing up (Figure 5).
The stub tenons used to attach the tails
to the frieze are stepped in so that any shrinkage of the tail
does not leave an unsightly gap in the joint (top). Structural
screws hold the tails to the 5/4 frieze board; any butt joints
are mostly concealed behind the corbels
Installation. After cutting the
mortises, the crew used TimberLok screws to fasten the tails
through the back of the frieze. We installed wall brackets and
planks at a comfortable working height below the eaves and
raised the assembly into place with a material lift. The rake
boards with attached tails went on last.
The plans called for 2-inch button vents through the frieze to
provide ventilation for the roof. In addition to these, we
installed the frieze assembly over spacer blocks to allow for
airflow behind the frieze board, filling the gaps between the
blocks with Cor-A-Vent, for a bug screen. We screwed the
assembly through the frieze board and blocks into solid
framing, then plugged the screw holes.
We set the top of the assembly 3/4 inch lower than the tops of
the rafters to account for the thickness of the 1x4 V-groove
soffit. After installing the soffit planks, with butt joints
over the tails, we set the last course of roof sheathing,
gluing it to the tops of the soffit boards (to avoid nailing
through the soffit) and securely nailing it to the rafters and