Boosting wall insulation; ozone
Q: Does it make sense to apply rigid sheets of insulation to the outside of my house to boost efficiency as part of a retrofit? How does it compare to creating a double stud wall?
A: Yes, absolutely. Rigid insulation sheets are one of the best things you can do when renovating the outside of a building before new siding goes on. It boosts effective insulation action and makes stud wall cavities warmer for any given outdoor temperature. This last benefit is important. Warmer stud cavities greatly lessen the chances condensation will occur inside wall cavities during cold weather. Double-wall construction boosts the energy efficiency of a building too, but it’s much more difficult to install in a retrofit situation.
Fireplace smoke smell Q: How can I get rid of a smoky smell in our living room where we have a wood-burning fireplace? This smell has persisted long after we ended the fire season.
A: Smoke odours often persist for a while, especially with fireplaces. One reason is residual ash and the smell of soot that wafts down the chimney. Is your fireplace as clean as possible in and around where the logs burn? Also, is the flue fully closed to keep chimney smells out between uses?
If you want to take things a step further, consider an ozone generator. This is a plug-in electric device that creates airborne oxygen molecules made of three oxygen atoms instead of the usual two. This three-atom configuration is ozone and it’s somewhat unstable.
It results in free oxygen atoms floating around in the air for a while, oxidizing compounds that cause odours and eliminating them. Restoration contractors use ozone generators to eliminate smoke odours, and they’re used to deodorize hotels and vehicles. Ozone can be irritating in high concentrations, but that’s an easy problem to avoid.
Wear a respirator if you have to enter a room being treated with ozone, or just leave the room closed for a few hours after the ozone generator has completed its cycle. Ozone automatically reverts back to harmless, ordinary oxygen in time.
Soggy cathedral ceiling fix
Q: What should I do to prevent water leaks that damaged the kitchen cathedral ceiling of my 1970s house after a thaw last winter? There are 30 potlights in the ceiling. The insurance team feels the cause could be a roof leak, condensation or both.
A: You’ve got all the makings of a classic Canadian cathedral ceiling condensation problem. If warm, indoor air is allowed to sneak into unheated spaces such as your ceiling, the air will cool during winter and lose its ability to hold moisture. This moisture could come out as water droplets within the batt insulation in your ceiling, but more often it appears as hidden frost.
The longer the cold spell, the more frost accumulates. Eventually even a Canadian winter gets warm, and when that happens week’s worth of frost melts. That’s probably what ruined your ceiling since the roof doesn’t leak when it’s just raining outside.
The solution is to have closed-cell spray foam applied to the underside of your roof structure during restoration work. When applied thicker than three inches, closed-cell spray foam acts as its own vapour barrier, preventing the migration and condensation of warm indoor air into the roof structure. Spray foam is definitely the way to go given all the recessed fixtures you have.
There’s really no way around this because so much indoor air can leak into the ceiling around them. Be sure to use IC-rated recessed fixtures fitted with LED bulbs. Besides using much less electricity, LED bulbs run cooler than incandescent. You’ll also need to use fibreglass shingles to withstand the heat of an unventilated roof.