Window installation in Des Moines
A good window installed badly leaks air and water like a bad window. Most of what makes a window warm in a Des Moines January happens in the inch of gap between the new frame and the house, so the installation method matters as much as the brand.
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Three kinds of installation
- Insert (pocket) replacement. The new window goes inside the existing frame. Faster and less disruptive, and the interior trim usually stays. It needs a square, solid old frame, and it reduces the glass area a little.
- Full-frame replacement. The old window is removed down to the rough opening. The installer can see and repair rot. Insulation goes around the frame and the opening gets flashed properly. More labor and new trim.
- New or enlarged opening. Cutting a wall for a new window, or making a basement opening bigger for egress, changes the structure. Cutting a new or larger opening, such as a basement egress window, changes the rough opening, so it falls outside that exemption and needs a permit.
What a careful install looks like
- The rough opening is checked for rot and water damage before the new window goes in.
- The sill is sloped or flashed so water drains out, not in.
- The window is shimmed so it sits plumb and square. It should open and lock without forcing.
- The gap around the frame is filled with low-expansion foam or insulation, not stuffed so tight it bows the frame.
- Exterior capping or trim is sealed, with weep holes left open.
- Every sash gets opened and locked in front of you before the crew leaves.
Old houses need extra care
Many Des Moines homes from before 1940 have weight-and-pulley windows with hollow pockets beside the frame. Those pockets are a big source of drafts, and a full-frame job lets the installer insulate them. Iowa's lead-safe renovation rules cover target housing, meaning housing built before 1978, plus pre-1978 child-occupied buildings such as daycares. The EPA says window replacement is always covered by the lead renovation rules, regardless of how many square feet of paint it disturbs. In Iowa, a company that does renovation in that housing must be certified as a lead-safe renovator firm, and at least one certified lead-safe renovator must be assigned to each job. DIAL runs the program. Lead-safe window work.
Permits
The City of Des Moines' permit exemption policy (effective July 1, 2023) lets window replacement skip a building permit only when the rough opening keeps its size and the finished egress opening is not reduced. The window also must not be one the code requires for smoke control, fire separation distance or safety glazing. West Des Moines, Ankeny, Urbandale and the other suburbs run their own building departments. Ask the installer who pulls the permit and check with the city before work starts. Permits and historic districts.
Questions Des Moines homeowners ask
Is full-frame installation better than insert?
Not always. If the old frame is solid and dry, an insert window can perform well for less money. If there is rot or water damage, or hollow weight pockets, full-frame is usually worth it. Ask the installer to explain which method they chose for each window and why.
Can I install replacement windows myself?
Homeowners can work on their own property, but window work on a pre-1978 house still means disturbing lead paint, and a poorly flashed window can rot the wall below it. Most manufacturer warranties also have installation requirements; read them first.