Door and Window Installation: Details Make All the Difference

Have you ever walked by a window and felt a cool draft coming in? Looked across the room and saw light shining through the cracks of a door? Has water ever found its way onto your floor during a rain storm? For all you DIY’ers or homeowners, you may be shocked by how basic techniques of door and window installation can go a long way! Working through the smallest of details has a huge impact to ensure homes are built to last.

For newer homes, you have the benefit in most jurisdictions where the IRC (International Residential Code) and the IECC (International Energy Conservation Code) dictate the minimum requirements of things like flashing, insulation and energy requirements that ultimately protect homeowners and ensure the quality of the finished product. Unfortunately, these are not always caught by an inspector or even known by the general contractor. Luckily, we at PCA don’t need to worry as we have partnered with amazing contractors who are diligent about quality control.

Now, if you live in a much older home (say built in the 40’s), there was much less oversight, knowledge and enforcement at the time the home was built leading to lack of quality control over things such as air sealing, head flashing, sill pans , etc. So, if you are the DIY’er or just a curious homeowner, here’s a little 101 on some important terms and details that can ensure you’re getting it right the first time and know what in the world the contractor is talking about.

Rough Opening (R.O.) – The wood-framed opening that allows for the insulation of the window or door. These are typically ¼” – ½” wider and higher than the window/door to allow the door to be set in place, nailed and flashed. This leaves a gap between the door and window that needs to be filled.

Jamb Insulation/Expanding Foam – This is typically a spray foam applied insulation that fills the gap between the window frame and the rough framing. This helps stop air movement and leakage between the openings. The lack of this and weather stripping is the number one cause of a drafty door or window.

Weather Stripping – This is often a rubber or foam strip covered by a fabric-like material that sits between the operable door or window unit and the frame. This allows the door or window to seal and stop water, air, or even sunlight from passing through these gaps. These tend to get worn over time and usually are easily replaceable.

Nailing Fin – This is a little “fin” or piece of plastic or metal that surrounds the door or window perpendicular to the jamb. This typically has a bunch of holes that allow for nailing to secure it to the rough opening. While this isn’t always used or necessary, it is a very easy way to mount a window or door and allow for proper flashing techniques.

Sill Pan – This is the most overlooked item or is installed improperly. Similar to the head flashing, this is a break metal, copper or even plastic “pan” that goes under your door or window sill that gets flashed to the water resistive barrier. This allows any water that happens to get between the threshold and jamb to be caught and drain back outdoors. It is also critical that the pan has what’s called a backdamn (back leg) to properly control the water and let it escape. It is also imperative that the bottom of the sill and window is not caulked shut.

Jamb Flashing – This is a tape-like product that is applied to the water-resistive barrier that covers the wall sheathing and overlaps the nailing fin. This stops water and air infiltration through the opening.

Head Flashing – This is a metal or plastic material that is bent to form a “hat” for the top of a window or door. This allows the water running down the siding to hit it (not the window) and drip off. This also stops “driving rain” in heavy storms from getting between the window and sheathing that would ultimately rot the wall sheathing.

If you’re the DIY’er and looking to replace your front door or just the curious homeowner, hopefully you have learned a few new terms that have to do with the proper installation and sealing of your doors and windows. While not getting into the micro of walking you through installation means and methods, you now have a better understanding of what key items to look for or even to turn to your contractor and say “Hey, I kind of know what you’re talking about!”

Written by Doug Kuchta, project manager at PCA

Architecture & Interiors