This column in the real estate section introduces Low Down readers to Mike Reynolds, a former local homebuilder, LEED for Homes inspector and the editor of Ecohome.net, a free web resource for green building. For more building guidance, visit the Ecohome website or contact Mike at email@example.com.
By Mike Reynolds
The questions arise: I want to insulate my attic, what is the best way, and do I need a vapour barrier?
For older homes (and especially cottage retrofits, examples of which are commonplace in this area), insulating your attic is one of the best home upgrades for seeing a return on investment. You can easily be losing hundreds of dollars worth of heat into a poorly insulated attic every heating season, so payback can be pretty quick.
One of the most effective and affordable ways to insulate an attic is with blown-in cellulose. It creates a seamless blanket over the entire surface so heat won’t be creeping up between cracks like it can using fiberglass batts. Cellulose insulation is made almost entirely from recycled newsprint, so it’s quite affordable, and one of the more ecologically responsible building products you will find.
If you already have pink batt insulation up there, you can blow cellulose right over top with no problem. Keep in mind that you need to ensure proper venting and airflow through your attic. If any of this makes you scratch your head, it may be best to get a professional to take look.
It’s important to get this right because poorly installed insulation can cause serious moisture damage. As well, a fluffy pile of cellulose will limit your future access, so make sure everything is in order first, namely ensuring that kitchen and bathroom fans are vented outside instead of right into the attic.
As for vapour barriers, yes, you should have one if there isn’t one in place already. What you might want to look into are vapour retarder primers. Despite being seriously underutilized in the construction industry, they do the job well and even exceed building code requirements. In some cases, painting on a vapour barrier can be easier than crawling around in your attic with a sheet of polyethylene.
Another question: my house has a dirt crawl space, and our house smells a bit mouldy. I was told if I spray-foam the floor, that will fix it. Is that true?
With the number of cottages turned into homes in this region, it’s a fairly common problem. Yes, having spray foam installed from below is one solution, but all cases are different and there are sometimes much more affordable and better solutions. If your home sits on posts with air flow going underneath, go for it. The foam will stop air leaks, bugs, and moisture damage and keep you toasty warm.
Here in the Gatineau Hills, what we often see in cottage upgrades are full foundations on rock or dirt, with mechanical systems and sometimes furnaces down there. That can mean an endless supply of moisture finding its way into your living space. In a case like that, spraying foam under the main floor can trap both heat and moisture, and turn your crawlspace into a steam room.
With an enclosed basement space, it’s important to stop the moisture from coming up from the ground in the first place. This can be done by laying down polyethylene (common vapour barrier) for a fraction of the cost of spraying foam. You just have to work from one side to the other laying it down right on the dirt or rock, overlap it a bit, and tape it together.
Keep in mind that it does not need to be flawless or tightly sealed. Taping it serves mostly to keep it in place. The intent here is to stop moisture evaporation, not create an air seal. Do your best, but if access only allows you to do 90 per cent of the surface area, you’ve just removed 90 per cent of the problem.
Regulating home moisture can make your home healthier, more comfortable and last longer. A dehumidifier running full time will cost around $10 a month, and you will save at least that by not having to heat unwanted moisture in the air.