Remodeling contractor Mike Sloggatt demonstrates how to use a professional spray-foam gun to make a patio door (or any door) more energy efficient

I’m going to air-seal by spraying foam around the perimeter of this door jamb.

I use a foam dispenser gun with a nozzle attachement that threads onto the end and lets me spray into the tight spaces around the jamb. Another thing I like about a pro foam gun is that the foam is released at the very tip of the nozzle; this means that the foam stays fluid inside the gun. I’ve accidentally left a can on my gun for as long as two months and still been able to dispense the foam. With a pro gun you also use the entire can; you don’t have the waste that is typically stuck in the end of a disposlable, straw-type spray-foam can.

It’s important to use the right type of foam. Get a low-pressure, low-expansion, and closed-cell window-and-door foam. The closed-cell is going to stop the air movement, and the low pressure and low expansion is important because it won’t distort the frame. High-expansion foam can bow the jambs out and prevent the door or window from opeing properly.

The last thing I’ll do on the inside of an exterior door is seal the sill pan to the door threshold. I’m going to use a sealant for that because air could blow in, and when there’s air moving in, water could come with it.I put some painter’s tape over the visible portion of the threshold while I caulked and tooled the joint wher it meets the floor.

After the foam and caulk has cured, I go back and trim any excess foam that is out past the jamb. If I notice any voids in the foam, i’ll come back and touch them up with the foam gun. That will take care of the air-sealing and we can move on to door trim.