COUNTRY SKILLS

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Our clapboards and windows were so weathered that a gust from a proper northeastern would suck little puffs of snow into the north side of our living room. At first I covered the whole wall with plastic, but that's old-tech. I recently wrapped the house bit by bit with Du Pont Tyvek, a flexible plastic membrane that's placed between sheathing and siding in new homes. The Tyvek keeps wind from coming in but lets moisture out. After removing old clapboards, I stapled Tyvek over the exposed sheathing boards, placing tape over the staples and seams. As I tore out interior walls, I pumped silicone/latex tube caulk into seams between sheathing boards and into cracks and knotholes—but not into top and bottom of wall cavities. Air must be permitted to flow up and through the outer wall to ventilate insulation.

Outside, I nailed siding over the Tyvek. Had walls been thinner, I'd have applied rigid-foam insulation board before the clapboards went on. Or, I'd have erected super-insulated double walls inside—a partition of 2 x 4's staggered between outer wall members. Leaving a 2" airspace between double 2 x 4 walls filled with 3 1/2" roll insulation gives an R-value of 30 or more. (See "Super insulation" issue #101, Sept/Oct '86, p. 47.)

I chipped out loose beads of dried-out old caulking around casements, plumbing and utility conduits, carefully collecting and disposing of it. Old caulk may contain poisonous white-led pigment. I replaced it with silicone-latex, 30-year-life tube caulk. I use modern aerosol foam.

Foam Insulation

Canned foam is great stuff; it acts as both a vapor barrier and insulator rated at R-4 per inch. The nonexpanding kind is good for filling narrow cracks. To fill larger cavities, there are varieties that expand from 1 1/2 to four times the bulk that burbles out of the can. A powerful adhesive, it sticks to any clean surface, and a $7 can is equal to at least $20 worth of tube caulk. You can pump foam around electrical fixtures (but not inside the outlet box), and into inaccessible crannies. If foam oozes out of bounds, compress it with a wet putty knife or let it harden and trim with a sharp knife. Foam needs moisture to expand, so spray dry cavities with a little water. Have nail polish remover on hand to clean the jet. Foam will harden in the plastic applicator tube provided, but I find that soda straws serve as well, and "bendy straws" can reach hidden cavities.

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