February 28, 2011
In our last column, we discussed how to take the guesswork out of greening your home by making it more energy efficient. Today we’ll look at sealing the gaps behind baseboards for even better energy savings and comfort.
Baseboards hide the crack between the wallboard and the floor, but they don’t stop air from finding its way into the wall space and traveling throughout the house. There is, in fact, a lot of air moving within the interior and exterior walls, floors and ceilings – especially in older homes.
Since warm air rises, air from your furnace will take any path it can find toward the top of the house. When it travels through your walls on its way to the attic, the space between it leaves behind is replaced with other air, which creates a draft.
So how do you know if air is escaping through the crack behind baseboards? Air movement will often show itself as a noticeable draft, or as dirt marks from air exfiltration past the carpet.
There are usually two types of baseboard installation: hardwood flooring with a baseboard and quarter-round, or a fitted carpet or broadloom with no quarter-round. They require different sealing methods, which we will discuss below.
Hardwood flooring with quarter-round
This type is the easier one, because you can get direct access to the baseboards. You’ll need a caulking gun, some paper towels and thin rubber or plastic work gloves, as well as clear, low residual odor, paintable caulking like siliconized latex.
To seal, simply caulk three lines – 1) along the gap between the baseboard and the wall; 2) the gap between the quarter-round and the baseboard, and 3) the gap between the quarter-round and the floor. Use paper towels to tidy up smears or droplets.
Fitted carpet or broadloom with no quarter-round
This type is slightly more complicated because you’ll need to move the carpet out of the way to get access to the baseboards. To get started, you’ll need needle-nosed pliers, one-component foam in a disposable can with either a plastic tube or a gun dispenser and some thin rubber or plastic work gloves.
Most carpet is fastened onto a nailer strip positioned in front of the baseboards. The carpet is hooked onto the strip using a ‘kicker.’ Luckily, carpet loses its stretch within a few weeks after it is installed, so it’s easy to lift by taking some needle-nosed pliers and pulling it up from one corner, allowing you to literally unzip the carpet from the nailer strip along the wall.
Once the carpet is rolled back, inject the foam into the gap beneath the baseboard to fill and seal the crack where the wallboard meets the sub-floor. Because it’s impossible to have precise control of the foam coming out of the can, the entire gap will be filled. Should any foam get onto the top face of the carpet by mistake, either immediately clean it off while it’s still soft using an acetone foam cleaner, or wait until it has completely cured (about 24 hours) and scrape it off with a knife.
Foam expands during the curing cycle, which means it will form a bubble of excess material beyond the plane of the baseboards. There are two methods for dealing with this. The first is to allow the foam to cure and expand fully, and then trimming the excess material with a knife. However, this method is time consuming, dusty and usually you’ll find yourself trimming the foam a number of times to try to fit the carpet back.
The preferable method is to wait until the foam is tack-free and fully expanded (usually 10-20 minutes), at which point you can roll the carpet back, using it to push the foam under the baseboard and returning the carpet to its original position on top of the nailer strip.
This simple, quick and low-cost comfort improvement project can help make your home healthier, safer and cozier. It can also help you save money on energy bills.
