Subject: Re: Engineered Panels

From: [email-masked] (FoamLam)
Date: 7 Mar 1996 09:28:33 -0500

Stresskin panels are gaining wider acceptance in residential construction.
The first stresskin panels used in home construction were produced in the
1950's by Dow Chemical.  The technology is not new, just the awareness of
it
is.

The stresskin panel used in home construction is a sandwich of load
bearing
exterior skins with a shear resisting insulating core.  Exterior skins are
generally plywood or oriented strand Board (O.S.B.).  O.S.B. is most
widely
used for its size availability and consistent quality.  Insulating cores
are
of two types, expanded polystyrene (EPS) or Polyisocyanurate.
Polyicocyanurate offers a high initial R-value/inch and high burn
temperatures.  It is also not as widely available as EPS and comes with a
higher price tag.  The most common core material is EPS.  It is
affordable,
offers excellent insulation values at common wall thicknesses, has no
outgassing, and is recyclable.  EPS is commonly seen as "coffee cup foam".
The skins and core are bonded together with a structural adhesive under
pressure.  The structure then acts as an "I" beam.  The loads are carried
by
the exterior skins and the core resists shear as does the web of a steel
beam.

Manufacturers have various systems for connecting panels as well as for
assembling buildings.  Here at Foam Laminates of Vermont we use double
surface splines for panel to panel connections.  Splines are 3" wide
strips
of OSB that fit in grooves directly behind the skins at the panel joints.
They are nailed or screwed in place and form a continuous connection.  The
panel joint is also provided with a groove we call a foam expansion
channel.
This groove runs the length of the panel and accepts a spray expansion
foam
to seal the joints.  To assemble a building a simple procedure is
followed.
The first floor deck is built or a slab is poured.  2x nailers are
installed
flat on the deck in the location of exterior walls.  Panels are slipped
over
these nailers and nailed through the skins into the nailers.  Corners are
connected with 2x nailers and pole barn nails.  The top plate is installed
in
the panels.  A doubler is attached to the top plate to connect interior
walls
and break joints in the top plate.  The next deck is built atop the panels
in
the same manner as conventional framing.  Continue as before.  Roof
systems
are very wide ranging.  Panels do not work in the same way that rafters
do.
Panels require structural support at the ridge and mid span depending on
overall span.  Timber rafters also work well.  Panel systems don't lend
themselves to hip and valley framing.  It can also be very cost effective
to
truss a flat roof.

Studies have shown that structural panel building is at least as cost
effective as conventionall framing if not more so.  Bear in mind that
studies
are conducted by people who have experience in panel building and are
working
with a design that lends itself to panels.  Work with a manufacturer or
builder who has experience or be ready to learn on the job.  It is easy to
learn it is just hard to keep everyone happy while you do it.

To find panel manufacturers you can contact the Structural Insulated Panel
Association at 202-347-7800

If you would like more information E-mail us at [email-masked] or call
1-800-545-6290

Dan Maxwell
Foam Laminates of Vermont
P.O. Box 102
Hinesburg, VT  05461

Web Site http://members.aol.com/foamlam/flvweb.htm