The exterior side of the wall framing for our healthy house
was first covered with an aluminum foil wind barrier. I had originally
planned on using a foil-kraft paper-foil sandwiched material.
However, the contractor expressed a concern that over a period
of years, the aluminum foil might cause the steel framing to corrode
if they were put in direct contact. Rather than risk that, we
decided to use regular builder's foil, with aluminum on one side,
and kraft paper on the other. Having paper exposed toward the
inside of the house isn't ideal. However, the paper is relatively
low odor, and it will be isolated from the house by being on the
outside of the airtight barrier. It is also covered by insulation.
The purpose of the foil is to minimize air movement in the
wall cavity. It can also be a place where inside to outside temperature
and humidity differences can meet, so water can condense there
and flow down near the outside of the building, rather than near
the interior wall.
The builder's foil was taped together using Polyken
#339 aluminum foil tape. The #339 uses a low odor adhesive. For completeness,
the foil was also taped at its seams on the inside of the building (on the kraft
paper side). Polyken recently changed their name to Tyco Adhesives.
The aluminum siding was attached on top of the foil, from the
bottom up. Each segment of siding was screwed to the framing,
creating a weatherproof seal from segment to segment. The screws
used for X bracing mentioned earlier turned out to not be a problem.
However, because there was no plywood behind the siding, the vertical
seams along each row of siding were more visible than they should
have been. The installers took extra care to put bracing on the
inside of the wall to push the siding out just a little, to make
the seams less visible.
The siding is painted at the factory. Aluminum doesn't corrode
or rot or wear out, although it does dent. It shouldn't need to
be painted for 20 years or more, and it cleans up beautifully
with just a hose. Surprisingly, it is widely used on the east
coast, but it is not very popular in the west, where people seem
to prefer stucco.
Unfortunately, siding does get dirty. We found that a hose
works pretty well for light dirt, but that we really need a pressure
washer for the heavier stuff. We also have a long brush with a
water sprayer on the end of a pole that works pretty well for
the walls that aren't up too high.
You might be interested in the following book about siding,