Easy Window Install & Using Spray Foam

I helped a friend install replacement windows today. The original windows were double hung sash weight windows, quite old. Wanted to show you a few things about how to install replacement windows. To install new windows, you first have to remove the old ones. This is not hard.

We will be using the frame of the original window. The replacement windows slide inside the existing frame. Most replacement windows need to be custom ordered. Its important to measure each window, as they are all slightly different.

Old window removed

To ready the window frame for the new window, you remove the trim from the inside, and the bottom window will tip out easily. There is a thin wooden strip between the upper and lower windows, and once that is removed, the upper window comes out. You may have to disconnect the sash weights, though the sash weight cord is usually broken already. The windows may need to be lowered or raised a few inches to get past the sash weight pulley.

The replacement window then slides into the existing window frame.

Now the fun part: Spray Foam.

Its probably the insulation obsessive in me, but I love to use spray foam. For these windows, we had to insulate a lot of cavities around the original windows, so this called for a lot of spray foam!

There are several kinds of spray foam, different kinds expand at different rates, and some cans of foam can be used more than once.  Some cans, once you start foaming, you can’t stop, or the foam hardens in the spray tube. Others you can clean out the spray tube and use it again later.

Cavity Filler and Door Foam

The two main kinds of spray foam for our purposes is cavity filling “Big Gap Filler” and minimally expanding “Door & Jamb Foam” . The names are pretty self explanatory. You may not realize it, but the cavity filler type foam, if used when sealing a door or window, can warp the wood door frame. For doors and windows, we use the minimally expanding foam to fill in the gaps. For big open spaces, we use the big foaming stuff.

Most spray foam cans have to be held upside down when using, if you don’t, all the propellant leaks out, leaving the foam in the bottom of the can. It can be helpful to have an additional stray handy when you have to work up close to a ceiling, the additional straw allows you still tilt the can yet get the foam where you need it.

Cavity Filler Foam on the bottom, and Door & Jamb foam on top

Most important is to wear gloves and clothes you don’t care about. You will get foam on your clothes, and it doesn’t come off. I have ruined a lot of clothing with spray foam. I invented the trash bag work smock for impromptu spray foam jobs.

Trash Bag as spray foam application uniform

What do you use spray foam for? Let us know below: