- Q.The architect for a new
home in Virginia has specified a product called Energy
Brace sheathing instead of plywood or OSB. The product
feels like cardboard covered with foil. The
manufacturer claims that the product has energy
benefits. Am I right to be doubtful?
editor Paul Fisette responds: I believe that
the energy benefit of this sheathing product is
marginal at best — for all practical
purposes, the benefit is nonexistent in cold to
moderate climates. The R-value of the sheathing is
less than the R-value of 1/2-inch OSB or plywood.
The manufacturer’s energy claims are based
on the ability of the foil to reflect radiant heat.
In order for foil to work as a reflective barrier,
an air space must be maintained on at least one
side. If the reflective surface comes in contact
with another surface on both sides — for
example, siding on one side and insulation on the
other — then heat can be conducted through
the sheathing, and the amount of reflected
radiation will be insignificant.
The other problem is that the foil
surface’s ability to reflect radiant
energy works best when it is bright and shiny. When
the surface collects dust, the reflective