We thought that this was common knowledge, especially in the contracting world, but we realized that a lot of people didn’t know what the proper forms of insulation were, or how they should be used. There were homeowners surprised at the insufficient insulation they already had or had paid a contractor to install after being told that it was okay. An electrician and a plumber that we work with both had horror stories of other contractors that they had done work for that were not insulating renovations properly. This was something that was alarming to us, as not insulating properly behind your walls can cause all sorts of problems down the line. Dangers such as locked-in moisture, mold, mildew, and poor climate control.
In a typical North-American unfinished basement space, you will find a batt-style R5 blanket insulation that is installed halfway down the concrete walls. That is basically the minimum for the home builder to be able to pass their final inspection and give the keys to the homeowner.
When a homeowner decides to finish their basement, a lot of contractors we are hearing about are coming in and telling them that they can just leave that minimum insulation and install the drywall on top of it. It is cheaper for the contractor so they can keep their quote low, and they are in and out of the job faster, but as a homeowner, you are going to be left with a smelly, moldy, mildewy basement after a few years.
Why is that? The R-value of that basic insulation, which is the resistance of heat flow and air traveling through, is not high enough. The higher the R number the more impenetrable it is to heat and air passing through. In our region (Ontario) the suggested insulation for a basement is at least R22. It is always a good idea to look at what the minimum R-value is for your region, as temperatures and conditions differ quite a lot around the globe, so finding out what your local code requires is very important. We prefer to go beyond the minimum to ensure the best and most effective insulation for our jobs.
One of the other problems with leaving up the existing half-wall insulation and putting up walls in front of it is that you are creating an air gap. What is going to happen in that air gap is that hot and cold air are going to get trapped and mix together, which will cause condensation. That condensation will cling to your vapour barrier, your drywall, and the wood studs, and will create mold and mildew that will fester and grow and take over your basement. Nobody wants that dank stinky basement!
Just as important as the insulation, you want to make sure that you have a proper vapour barrier put up to create a solid air break. There are a lot of smart vapour barriers available now that change their permeability to be able to allow any humidity that is in there to escape so that you don’t end up with that trapped condensation. Also, make sure that the old insulation blanket and vapour barrier come down before you put up the new insulation. You only want one vapour barrier and you want it right behind your drywall, so you don’t create an air trap between the layers.
Main/Upper Floor Insulation
Upstairs as well, you are going to have something similar. If you look behind your walls you are likely going to find the minimum required insulation. Generally, the main and second floors will have an R14. You want at least R22 in those floors as well to make sure that you are keeping all the heat and A/C that you are paying for on the inside of your house.
Around the windows, we often find that there isn’t any insulation at all, and if there is, it is old or sparse. If you are renovating and have access to those areas, take a minute to make sure that any gaps are well insulated to maintain a good seal.
You want to make sure that you have sufficient insulation up in your attic as well. If you have access to a thermal gun it can be a lot of fun to go around your house, looking at some of the different spots where the insulation might be insufficient. I checked the ceiling of different rooms on the upper floor of my house with a thermal gun and I could see some cold spots where someone must have been up in the attic and moved some of the insulation. It’s a good idea to check your attic and make sure that the insulation is evenly and thoroughly spread across the entire space, or to have some new insulation blown in if you notice that it is lacking. You want to make sure that the top of your house is just as sealed as the walls. Think about what you do for yourself in the winter time—you would wear a toque (or a winter hat for our American friends) to keep your head warm and keep the heat from escaping your body, so make sure that the cap of your house is also covered and secure.
Building science has come a long way to making homes more efficient and better sealed from the outside. One way to better insulate is with exterior insulation. There are many options available when it comes to exterior insulation, make sure to choose your products carefully. By insulating the outside, you are getting an extra layer of protection to keep your climate control on the inside of your house. Your heating and cooling bills will be lower, and the life of your furnace and air-conditioner will be extended by not overusing them. You are going to spend a bit more money upfront while doing your renovation, but you will be saving money over time by making your home more efficient.
Keeping it green
People are becoming more aware of and striving toward eco-friendly homes. The more properly insulated homes, the less energy we are wasting, the better it is for our environment. There are also some great products out there that help with keeping our ecological footprint down. One product that we use is called ROCKWOOL stone wool.
On a Budget
If you are someone who is a DIYer and has a skillset where you could potentially do your own insulation, you could definitely save yourself some money by going with a batt-style insulation. Make sure to wear the proper protective gear and be ready to work up a sweat. It is important that you get the right products and take your time doing it right.
Insulation is something that is hard to get people excited about, but it is something that we should be paying more attention to. Sure, it isn’t going to help the aesthetics of your house, and you would rather spend your money on something that you can see, but by making the right insulation choices you will have increased energy efficiency and less energy spent on heating and cooling. If you invest in what is behind your walls you will end up saving money in the long run, so you can upgrade to that kitchen island you’ve been dreaming of in a much warmer and safer house.