How To Look At A House
McGarry and Madsen's home inspection blog for buyers of
site-built, mobile/manufactured and modular homes
What are common window inspection problems?
Saturday, September 29, 2018
Here’s how we look at windows: we start while examining the exterior of the house, looking for missing or damaged trim, deteriorated caulking, clouding due to lost insulating gas in double-pane windows, and bent, damaged or missing screens. We also check for flashing at the top of the window trim. Later on, while testing sprinklers, we note any heads that are spraying on the windows.
Then, inside the home, we test the window locks, open the the window, and look for evidence of water intrusion—such as powdered or stained drywall/plaster and cracks due to movement of wet wood. We verify that bedroom windows have emergency egress size openings (big enough for a person to get out and a fireman with a backpack to get in).
Also, while doing an infrared scan of the interior walls and ceilings we pay special attention to the areas surrounding each window. Most of the water intrusion damage observed is found in the wall framing below the window.
Here’s our top 10 list of common window defects:
1) Fogged windows due to lost insulating gas - An insulated window has two panes of glass with an inert gas sealed between them which provides the thermal insulation. When the seal is broken, through damage or deterioration, moist air and dust come into the center area and condense on the interior surface of the glass, eventually building up a hazy film. The leakage of the insulating gas also reduces the R-value of the window. See our blog post What is causing a foggy haze on my windows? for more on this.
2) Damaged wood trim on exterior - Seasoned carpenters like to talk about avoiding “water traps” when installing a window sill and trim. A water trap is any surface that is not sloped downward away from the wall and allows rainwater to sit until it evaporates. These areas soon develop spots of wood rot and, if left unrepaired, allow water to enter the wall and begin to rot the wood framing.
3) Cracked window panes - A cracked glass pane lets a minor amount of outdoor air into a home, but is mostly a safety concern. The fracture line shifts slightly over time and develops a sharp raised edge. Also, once the glass is cracked, any further stress will cause it to shatter.
4) Lack of exterior flashing - One hallmark of a quality building contractor is a strip of metal flashing that covers the top of the window trim and is secured behind the siding directly above the window, as in the photo below. It’s an effective deterrent to water entry at the top of the window. Some builders depend on a bead of caulk to seal the seam between the siding and top trim, but the caulk eventually fails.
5) Missing or damaged screens - Sometimes they are stored in the attic or a corner of the garage. We check around before declaring them missing. To learn more, go to our blog post Are openable windows required to have window screens? Will windows with no screens pass a home inspection?
6) Windows do not open or difficult to operate - We test each window that is reasonably accessible, and note any problems operating them. If the seller has furniture in front of the window, or delicate bric-a-brac on the window sill, sometimes can’t risk moving the belongings to test the window.
7) Evidence of water intrusion - Staining, especially around or below the window sill, is our visual clue of water intrusion. Further evaluation with a infrared camera and/or moisture meter follows.
8) Broken locks - Older window locks that don’t function can be due to damaged lock hardware or misalignment of the sash.
9) Missing operating handles - Can’t test the window without them.
10) Lack of tempered glass at required locations - We look for the “bug” (manufacturer’s tiny imprint on the glass indicating tempering). See our blog posts Where is safety/tempered glass required for the windows of a house? and How can I tell if a window or glass door is safety glass? for more on this subject.
“Fenestration” is a fancy word that architects use to describe the door and window openings in a building. Because problems often show themselves around these openings, we look at each of them carefully.
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To learn more about doors and windows, see these other blog posts:
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