I run a specialty millwork shop in Narragansett, R.I. Over the
last 25 years, I’ve developed a strong working
relationship with my oldest and largest customer, Baud
Builders. One of the first things Dave Baud and I do when we
review a set of plans for a new home is identify
out-of-the-ordinary architectural components that can be built
off-site in my shop. This approach takes some time-consuming
tasks off the framing crew’s back, allowing them to focus
on getting the basic building shell closed in.
That’s how we handled the front entry featured here
— an arched-roof portico projecting between gambrel
gables above a rounded deck. The front corners of the roof rest
on composite columns standing on flared-skirt half walls. The
gambrel eaves terminate on the portico roof, creating as
complicated a junction of rooflines as you’re likely to
When I began the job, only the height and depth of the entry
inset had been established on site, but the window immediately
above the portico roof had not yet been framed. So to play it
safe, everywhere that the porch assembly would join the main
structure, I allowed 1 1/2 inches of clearance for fitting and
shimming. We also had the site crew hold the adjacent roof
framing back a couple of feet until the portico roof could be
dropped into place.
Keeping It Light
I began by making the architrave, the perimeter beam that
supports the roof (see Figure 1). Instead of
using framing lumber, I built a box beam with 1-by pine and MDO
plywood. Hollow construction allows a higher degree of accuracy
and dimensional control than conventional framing. And hollow
members are strong but light, so they’re easier to move
around in the shop and onto the site for final assembly. Also,
the open construction provides drying airflow within the
structure and enables the electrician to install downlights and
run wires without drilling. The architrave beam became the
platform on which I built the roof.
Figure 1. The architrave was made first, in box-beam
fashion for lightness and maneuverability in the shop. It
served as the working reference for the layout of all the other
components. The horizontal flanges provide screw attachment
from below for the trusses, while the projecting spacers act as
Roof trusses. For the barrel-roof
framing, I made lightweight open trusses with curved 2x4 chords
sandwiched between 3/8-inch AC plywood skins. The front part of
the roof spanned 16 feet, so I was able to use two lengths of
8-foot plywood laid out in mirror image to make the skins
(Figure 2). We joined the skins end-to-end
with plywood mending plates and fast-setting, permanent HiPur
hot-melt adhesive (800/669-4583,
titebond.com). To make the chords, we
kerfed the 2x4s on a chop-box at 3-inch intervals, then bent
them against stops hot-melt-glued to the workbench.
Figure 2. The arch-topped roof trusses are made from
2x4 chords skinned with 3/8-inch plywood. To form a graceful
curve, the author bent a flexible piece of pine between the
roof’s rise and run and traced the profile onto the
plywood (top left). The first half-rafter was carefully cut
out, then used as a pattern for the others (top right). The
plywood cutouts were joined end to end with plywood plates,
then glued and stapled to both sides of the framing members,
creating strong, lightweight trusses 16 feet long
I made the roof in two sections, front and rear, to make it
easier to scribe to the building if needed (Figure
3). The rear section was sized to fit within the entry
recess, a span of about 9 feet. These skins are single sheets
extended at either end with plywood fillers.
Figure 3. The roof was made in two pieces, a front
rectangular section (top) and a rear section (bottom left) cut
out to wrap a projecting bay. The sheathing was applied in
three layers, stepped back at the joint between the sections to
allow for a strong overlapping layer of sheathing to be applied
on site. The small overhang across the front of the roof
(bottom right), made from cedar, was blended at the corners
with a filler of epoxy and sawdust, then sanded flush.
We sheathed the trusses with three layers of 3/8-inch AC
plywood, fully bonded with spreadable Excel polyurethane
adhesive (800/779-3935, excelglue.com) and stapled. We stepped the
plywood layers back from the joining edges so that we could
make a seamless union on site.
Next, we tackled the two L-shaped half walls (Figure
4). To ensure square corners and bottom-up uniformity,
I cut six identical plate patterns out of 3/8-inch plywood and
laminated each of them to pieces of 2x8 plate stock, then
trimmed the plates to uniform size with a pattern bit. Four of
the plates were used in the half walls, and the other two were
set aside for mounting on the deck framing as installation base
plates. We framed the walls with pressure-treated lumber and
sheathed them with 3/8-inch AC plywood. We extended the
sheathing 1 1/2 inches beyond the bottom plate to create a
nailing flange, keying the wall to the base plates on the deck
framing (see illustration).
Figure 4. The flared L-shaped half walls (left) were
built on pressure-treated plates (right) that were carefully
machined to fit matching plates attached to the deck framing.
The wall sheathing runs past the bottom plate to create a
captive flange for the base plate, so that the wall could
easily be dropped into place on site.
To speed assembly, the author designed the portico as five
discrete parts built to fit neatly together: The roof assembly,
the architrave beam, the columns, the half wall and its cap,
and the deck framing. Plates on the framing received the half
wall, while round mounting blocks on the wall cap accepted the
column bases. Similar blocks on the bottom of the architrave
captured the tops of the columns, and the trusses in the roof
assembly slipped in between pairs of wooden ties projecting
from the top of the architrave. Installation of the entire
portico took less than a day.
For the flared wall profile, we cut curved blocking on a band
saw, using a pattern jig to speed the operation. The same flare
wraps the entire building, so we provided nearly 1,000 of these
blocks in all. They’re set on a pressure-treated cleat
and nailed to the wall at regular intervals. We glued and
stapled 3/8-inch sheathing over the blocks, followed by a wider
sheet of 1/4-inch lauan plywood to help fair the curve onto the
The railing cap is 8/4 mahogany, mitered like an upside- down
“V” to shed water and glued with two-part West
System epoxy (866/937-8797, westsystem.com), a gap-filling and
completely waterproof adhesive (Figure 5). We
avoided fillers or plugs by simply gluing the cap to the wall
with polyurethane construction adhesive.
Figure 5. Here, bevel-edged mahogany
planks for the railing cap are glued together with epoxy, the
joint held snug with shipping tape until the adhesive cures
(top left). To create a flat bottom for mounting on the wall, a
filler piece was added and bonded with more epoxy (top right).
Circular mounting blocks for the composite columns were
installed in the shop (bottom); the lower disk matches the
outside diameter while the upper receives screws driven through
the column and concealed by decorative plinths. Note the weep
holes for drainage and ventilation.
To capture the composite structural columns supporting the
roof, I made circular top and base plates out of cedar.
I’ve found that a surprising amount of moisture can
condense inside these columns, so I drilled weep holes around
the base plates. The plates are glued with epoxy and screwed to
the railing caps. I scribe-fit the base of the proprietary
decorative plinths to the peaked railing profile and added
weeps along their front and back edges.
Framing the Deck
The pressure-treated deck framing is an integral part of the
portico and was built in the shop along with the other
components. I made the main body of the deck as a unit and its
bowed front as a bolt-on section. I drew the radius on the shop
floor with a trammel and built directly to it. To make the
bowed rim joist, we kerfed a 2x10 at 3-inch intervals to within
1/4 inch of the face. To form the concentric starter tread, I
made uniform lookout blocks and hung them by cleats from the
back of the deck’s rim joist at even intervals. The
resulting radial layout created a built-in bending form for the
starting riser (Figure 6).
Figure 6. Kerfed lumber was used for the semicircular
deck frame (top left), which became a bending form to make the
curved treads. The author ripped 1/4-inch-thick strips of
meranti decking, then laminated them with two-part epoxy. Poly
sheeting contains the squeeze-out and prevents the clamps from
becoming permanently bonded to the wood (top right). In similar
fashion, the roof module was used for bending the arched trim
Laminated Decking and Trim
We used 5/4 red meranti for the decking. To make the curved
tread and deck nosing, I ripped 1/4-inch strips from the
meranti and used the deck frame as a bending form. If you keep
track of the rip sequence, you can reassemble the boards with
the grain pattern more or less intact. We brushed the bonding
faces with two-part epoxy, wrapped the strips in 4-mil poly,
and used plenty of clamps. To minimize cleanup, we protected
the outside edges with a bond-release tape. After the epoxy
set, we trued the surfaces by sending them through a planer.
The finished thickness wound up at just under an inch, so I
passed the rest of the decking through the planer at its final
setting to match.
To complete the deck module, we cut all of the planks to fit
against the curved nosing and labeled the boards in sequence
for installation on site.
Roof trim. The laminating process was
much the same for the roof’s arched trim, which we made
from clear western red cedar.
The roof’s exposed end panel is protected with Ice &
Water Shield (800/444-6459,
graceathome.com) and faced with
1/2-inch-thick Azek sheeting (877/275-2935,
which we installed over a short overhanging cap that the
roofing contractor clad with lead-coat copper in the shop. I
cut the Azek to fit loosely and let it float behind the cedar
trim. This allows the PVC material to move freely with thermal
expansion. I also set the panels on skip blocks so that any
water that found its way behind the panel would drain out
With a crane standing by, we loaded the components on a flatbed
trailer and towed them to the site. We first lifted the deck
frame into place, leveling and shimming it, then bolting it to
the building with LedgerLok screws (800/518-3569,
fastenmaster.com). The base plates for the
half walls were already screwed to the deck frame in the shop.
I patterned their locations directly from the architrave,
ensuring accurate alignment with the column plugs overhead. All
we had to do was to lift the two walls off the truck and fit
them onto the base plates (Figure 7). We then
lag-bolted the walls from underneath, through the base
Figure 7. On site, the crew aligns and levels the deck
frame over prepared concrete footings before bolting it to the
building’s rim joist (top left). Next, the flared half
walls are dropped precisely into place and screwed to matching
base plates already mounted to the deck framing (top right).
After setting the columns, the crew installs the architrave
(bottom); note the pairs of vertical pine rafter ties, ready to
receive the trusses in the roof module.
The composite columns went in next. We set them on the railing
cap and screwed them to the blocks. The plinth bases slipped
down to cover the connection.
We had added secondary fascia trim to the architrave in the
shop, to cover Cor-A-Vent strips (800/837-8368,
cor-a-vent.com) that provide ventilation.
The ceiling was left open, to give the electrician full access
for wiring and lights. We would install the beadboard later, on
After we screwed the column tops to their corresponding cedar
plugs on the architrave, we were ready to lower the roof
sections into place. We installed the front section of the roof
first, carefully lowering it so that the trusses dropped in
between the vertical hold-downs protruding from the architrave.
The rear section of the roof required some scribing before it
could drop into place. We then completed the roof sheathing
between the two sections by gluing and stapling stepped layers
of precut sheathing at the joint.
The entire installation took less than a day, start to finish.
Total shop time ran about 250 man-hours. With the portico in
place, the framers completed the abutting roof lines and added
crickets to either side of the angle bay. The roofing
contractor finished the portico roof with lead-coat copper
flashing and an EPDM membrane.
Mike Rand owns Narragansett Housewrights
in Narragansett, R.I.