TIPS FOR TACKLING COLD COTTAGE FLOOR AND DRYING LUMBER
When adding insulation, take care that you don’t create space for rodents to build nests
Q What’s the best way to insulate the underside of a cottage floor that’s four feet off the ground? I was thinking of fastening insulated panels to the bottom edges of floor joists.
A Instead of your current plan, I’d fasten then to the underside of the subfloor, between floor joists. Resisting animal invasion is the reason why.
If you create a big, empty space between the joists, mice, squirrels and chipmunks will chew their way in and make magnificent nests in the spaces you’ve created. You won’t have this trouble if the insulation and protective boards are tight to the underside of the subfloor.
I’d start by cutting pieces of 2-inch thick extruded polystyrene foam to fit between the joists with 1/2 inch of space all around the foam.
Use thick construction adhesive to hold the foam in place. Something called PL Premium is my favourite.
Next, cover the foam with pieces of 1/2-inch exterior plywood, also cut to fit between the joists with a 1/2-inch space around the perimeter. Hold the plywood in place with more construction adhesive and screws driven up through the foam and into the subfloor.
Be careful to choose screws that aren’t so long they go through the floor completely. Fill the space between the plywood/ foam and the floor joists with spray foam injected from a can to seal the installation.
The only hitch in all this comes down to how consistent the space is between floor joists. You might have to do some custom cutting of the foam and ply to get a reasonable fit, but spray foam will fill gaps.
Be sure to use plywood for your installation rather than the less expensive oriented strand board.
DRYING HOME-SAWN LUMBER
Q Is there anything I can do to improve the way I’m drying a white oak log I cut into boards? I used a chainsaw mill to saw a 20-inch diameter log into twoinch thick boards for making furniture.
I’ve got the boards stacked in a pile in an unheated shed, off the ground and with 1/4-inch spacers between each layer.
How long will this wood need todry?
A I’d start by increasing the thickness of spacers you have between each layer of wood
— 1/4 inch is too thin given the width of wood you’re drying. You don’t want stagnant air to develop between the boards, promoting mould.
Most people stack fresh-cut lumber outdoors initially so the air circulation prevents mould, then move them under a roof for more drying.
You can save time by stacking indoors initially, as you have, but you should use a fan on the pile to speed initial drying so mould doesn’t form.
Air drying like you’re doing will get you down to about 12 per cent to 14 per cent moisture content in a year or so with hardwood as thick as you’ve got, but you need to get down to 7 per cent to 9 per cent for stable wood in a heated home.
Anything wetter than this and your furniture projects will warp, twist and crack as they do their final bit of drying.
The best way to lose that last 3 to 7 per cent is by bringing the wood into a heated workshop, then allowing the wood some additional drying time after you cut and plane for each construction step.
How much additional time? The only way to tell for sure is with a moisture meter.
Good ones are inexpensive and take the guesswork out of managing air dried wood.
Check the moisture content of the wood as fresh surfaces are exposed.
The good news is that you’re going to have some fabulous wood to work with. Air dried lumber is so much nicer to work with than kiln dried.
Steve Maxwell has been helping Canadians make the most of their homes, cottages and workshops since 1988. Get Steve’s articles and videos delivered to your inbox each Saturday morning at BaileyLineRoad.com