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Basement Finishing Success

Steve Maxwell

ARTICLE HIGHLIGHTS:

Steve Maxwell, casa GURU's Home Improvement GURU, shows a Homeowner how to spray his way to a well insulated basement renovation.

Q: What's the best way to insulate a basement that I'm planning to finish? I've been following the technical progress of spray-on foam insulation and it looks great. Trouble is, all ten of the contractors that I've asked to bid on my basement renovation job are completely unaware of the new processes and materials, and too skeptical to change their old ways. All they want to do is put up wood-framed walls with fiberglass insulation and carpeting on the floors.

A: As spray foam options have declined in cost and risen in quality, it's become a very good way to insulate basement walls, especially those troublesome areas where floor joists end at exterior walls. Erecting exterior wood frame walls to hold wires and pipes, then filling the cavities with spray foam applied by a contractor does a very good job indeed. It’s more expensive than applying sheets of foam directly to the walls, but it does an excellent job.

There are a couple of options for floors. Ready-made subfloor products like DRIcore or Subflor are quite good, especially when you want to preserve a bit of drainage underneath the finished floor. If your basement is reliably dry, you can get more insulation value by laying down sheets of 1”-thick extruded polystyrene foam on the concrete with plywood on top. Visit my website for a free downloadable illustration that shows some of my favourite basement finishing details.