Are you renovating your older home basement in Calgary and considering flooring options? Here’s what not to do: subfloors. Subfloors are not recommended for older unlevel Calgary basements, due to all the problems they can potentially cause. Because of Calgary’s foundation shifting over the years, subfloors are not a good idea. And, no matter how old or new your house is, at some point the floor is going to heave. It’s inevitable.
Subfloors can also cause issues if you have any water leakage, or the potential for leakage. It is very difficult to tell if water is getting underneath the floor and the airflow space beneath subfloors is very small, so it does not provide much ventilation. Moisture can get trapped underneath the subfloor and cause mould/mildew within 24 to 48 hours, which can lead to adverse health problems ranging from minor allergy side-effects to lethal toxicity. Though the space underneath the subfloor is meant to provide airflow to dry any water that gets in, depending on how much water you get under it, that small space may not be enough to keep the floor dry. If the water doesn’t escape, this could cause mold problems. Therefore, subfloors are not recommended in older houses if the floor is prone to getting wet.
So, what should you do?
We recommend simply leveling your floor. If the floor is heaved, have it jackhammered and repaired or replaced. If there are minor dips or slants, those can be leveled too. If it’s off by ½” or less, self-leveling concrete can be used. If it’s off by ½”-2”, use topping concrete (not recommended as a DIY project). Once the floor is leveled, you can go on to choose a better flooring option than subfloors.