Along the Jersey shore, porches are
a common feature on most new houses. These days, many builders here
are using Fypon columns that get slipped over pressure-treated
posts. My concern is with the structural connections at the top and
bottom. Most guys are just toe-nailing the base into a doubled-up
rim joist on the deck and throwing a couple pieces of metal
strapping over the girder to secure the tops. Is that enough to
hold the porch in place during high winds?
A covered porch detailed for coastal
zones must resist several powerful forces:
• Porch columns must be designed to resist lateral loads from
surge or flooding.
• The columns and beams need to resist wind uplift loads as
well as gravity loads.
• Because porches are exposed to the elements, their delicate
details take a beating from sun, wind, and rain. At their best,
they need to match customer expectations for a durable,
low-maintenance weather exterior.
Contractor Smokey Saduk of the New Jersey beachfront building firm
Haffelfinger and Standeven recently showed Coastal Contractor the
porch column assembly he uses on the company's custom homes. He,
too, relies on Fypon polyurethane columns, but he also opts for
other advanced synthetics, including masonry column bases, PVC-clad
rail systems, and custom-tooled Azek trim (Figure 1). All these
materials have a good track record for standing up to the coast's
continual salt- and sand-laden winds, with minimal use of caulking
Figure 1.The column shown above is
designed to carry an upper-story porch; details may vary slightly
for columns that carry both an upper deck and a lower deck.
However, the principles are the same for any porch/deck
configuration, as detailed in the illustration below: The exteriors
are composed of layered, weather-tolerant, low-maintenance
synthetic materials, while the inner structures are strengthened by
reinforced masonry, engineered connectors, and treated
Sited on sandy barrier islands, the houses Haffelfinger and
Standeven builds typically rest on deep treated-wood piling
foundations, tied together at the top with a reinforced concrete
grade-beam grid. These houses are anchored to the foundation grids
by 4-foot concrete block stem walls, with fully grouted cores and
rebar reinforcement. Stand-alone piers for porch columns are built
into the foundation gridwork. Above the grade beam, each column
base is built with 16-inch concrete block, reinforced with rebar
and concrete grout, and tied to the underlying foundation grid with
anchor bolts, as shown (Figure 2). The 4-foot block piers receive a
concrete stucco parge.
Figure 2.Column bases are tied to
the foundation grid below grade. Above grade, Saduk's crews lay up
4-foot piers of 16-inch-square concrete masonry block, with fully
grouted cores. Capping the block pier is a 20-inch-square bluestone
slab, with a 6-inch-square hole in the center to receive the base
of a 6x6 treated- wood post. The anchor bolt (top, center) will
hold down a galvanized steel engineered standoff post base
connector for securely attaching the wood post to the concrete
pier. This block pier has already received a stucco scratch coat
and will be given additional cementitious finish coats.
Columns for second-story decks often sit directly on the block
piers. But first, a bluestone cap stone is set on each pier, with a
6-inch-square hole cut in its center to receive the base of a 6x6
pressure-treated wood post. The foot of each wood post is anchored
in a galvanized steel post base connector, which restrains the post
from moving either side to side or up and down.
To construct the porch assembly, explains Saduk, the crew first
frames up the porch beam and porch floor, supporting the whole
assembly with temporary posts. Then the synthetic marble columns
with their base and capital moldings have to be sleeved over their
wood-post structural cores. The framers set the whole post assembly
in place, fitting the foot of the wooden post into its connector
and fastening its top to the porch beam above with framing
connectors and steel straps before removing the temporary posts.
Once the porch is trimmed out in Azek, and the Fypon base and
capital moldings are secured with screws, the underlying wood
structure disappears, completely wrapped in durable synthetic
finish materials (Figure 3).
Figure 3. The porch's wood and steel structure
is completely hidden once the porch receives its layered trim
treatment of Azek ceiling beadboard, tooled Azek trim, and Fypon
column base and capital moldings. In addition to its decorative
purpose, the completed porch is able to shoulder its part of the
design wind loads typical for a coastal home.
Porch decks form an important part of the weather-resisting system
too. Deck floors are fully sheathed with 3/4-inch plywood, then
waterproofed with Vortex spray-applied polyurethane (commonly used
as a truck bed liner; available from www.vortexsprayliner.com). The waterproofing extends
up exterior walls under the drainage-plane building paper and into
rough door frames, as well as up the base of deck posts. When
completed, the synthetic-clad porch will invite its owners to enjoy
coastal breezes and views, free from worry about leaks,
maintenance, or structural integrity. — Ted