Hi, we have a 20-year-old log cabin with a 3/4" painted plywood floor. We want to insulate it for heat issues but also because the cottage seems to be "smelling" in recent years. From the moisture coming up through the floor perhaps? What's the best way to insulate? The cottage has a skirt which is about 1/2 foot off the ground so there is some air circulation. Is there any way to insulate effectively from inside the cabin or does the insulating have to occur underneath?
Answer:
You may have to remove the sub-flooring but there is only one way to properly insulate in a case like this. Crawl space is a major source of mildew but that can be corrected. First, all insulation has to be removed from the crawl space ceiling - house floor. The whole dirt floor, with all its irregularities, has then to be covered with an impermeable material (6mm polyethylene, an old swimming pool liner, etc.). This has to be firmly and permanently sealed to the existing, well-applied perimeter wall vapour barrier – which should be covering insulation rated at least R-20. It also has to be taped to all perforating structural components (plumbing, support posts, etc.). That looks after the crawl space for most of the year. The vents on the walls have then to be adjusted so they can be opened and closed from the outside. This will negate the need for anyone to crawl around down there for seasonal adjustment of ventilation.
