How a window is framed hasn’t changed much over the years, and remains very standard in most, if not all, areas. The main differences depend on window location and how much load is present. This article may not make you a window installation expert, but at the bare minimum, you should now be better able to ask the right questions, know what to look for, and be better educated about your home. If you have any further questions, contact your local building inspector.
Manufacturer Window Framing Installation Instructions
- Pella Window Installation
- Anderson Window Installation
- Marvin Window Installation
- Kolb & Kolb Window Installation
Window Framing and Sealing Basics
King & Jack Studs
The king stud will span from the bottom sill / sole plate to the top plate. On the inside of each king stud will be a jack stud for additional reinforcement, and acts as the support for the window header. The proper framing will make sure that there is little…to no window movement…as a house settles, contracts, and expands with varying weather.
- Typical framing spacing between studs is 16″ on center. This can vary with the age of a home.
- The window header and framing material size will vary per window style, location of window, size of window, and building code. (i) A basement window on a 2 story home will need much more structure than a simple shed with little weight above the window. (b) A basement for instance should use 2×8 or larger header material while a small storage shed may only need 2×4’s and single jack studs.
- Older homes may have used 2×4 framing material; while over the years 2×6 walls have become the standard for better insulation.
- These are the studs underneath a window. They should be spaced and installed in the same way as main studs.
Window Shim Installation
This subject is debatable, and will vary. The window manufacturers mention using them in several places, as you’ll see in the install instructions. Some installers may just do the bottom shims where most of the weight lays, and then rely on the nail fin (refer to manufacturers installation instructions) for the remainder of the support. Cedar shims are readily available at home improvement stores.
Note: Some windows come with factory spacers for the bottom and leave an adequate gap for spray foam. Older windows most likely would have been installed using standard cedar shims, along with batt insulation laid down first in the window frame.
Window Framing Examples
Listed are examples on how to frame common window openings. Always check local building codes to ensure you are within the proper specifications of your specific area.
Window Spray Foam
Spray foam will ensure a more airtight area, opposed to just stuffing batt insulation into the gaps.
Note: Make sure you buy window and door spray foam. This foam behaves like a sponge where it easily compresses, while the gaps and crack version behaves more like rigid foam board, and can bind windows and doors when houses shift around.