Hail on Vinyl Window Frames: Check the Corners Before You Call It Fine

Most St. Louis homeowners walk the yard after a hailstorm looking at the roof, the gutters and the siding. The windows get a glance, if they get one at all. Vinyl frames are easy to overlook because they are not metal and they do not dent the way aluminum does. They do take hail, though, and the damage tends to sit at the corners, where the frame was welded together, and along the bottom sill, where water and grit collect. This page covers what to look for on vinyl windows and what to put in your file before the next freeze.

Why the corners show damage first

A vinyl window sash or frame is made from extruded profiles that are joined at each corner by heat welding. The weld is the weakest point in the frame. When a hailstone strikes the flat face of a profile, the impact usually spreads along the length of the piece. When it strikes a corner, the force concentrates on the weld, and the weld can open a hairline gap or crack that is visible only from a few feet away at the right angle.

Sills are the other common spot. The horizontal bottom piece of a frame sits lowest, so hail that bounces off the ground or off a deck rail can strike it from below and from the front. A sill cap that is cracked or pushed out of its track will let water sit against the frame instead of running off, and that water is what causes trouble over the next few winters.

What hail does to vinyl in St. Louis weather

Vinyl stiffens as the temperature drops. A frame that took a light hit in July can crack when the same spot is struck in early spring or after a hard freeze, because the material has less give. That is one reason the first walk after a storm matters. The damage you see on the first warm day may be smaller than the damage that formed at the time of the hit.

The freeze and thaw cycle does the rest. Water that gets into a hairline crack at a corner expands when it freezes, and the crack opens a little more with each cycle. By the second or third winter, a small dent at a weld can become a gap that you can slide a fingernail into. This is the part that makes a photo file useful. A dated set of close photos from the first week gives you a baseline to compare against later.

What to check on each window

• Corners. Look at all four corners of every sash and frame. Run a finger along the weld line. A gap, a dimple or a line that catches light differently is worth a photo from straight on and from an angle.
• Sill and sill cap. Check whether the cap is cracked, lifted or missing a piece. Look under the sill for granules or grit from the storm.
• Exterior trim and caulk. Hail can split the caulk line where the frame meets the brick, stone or siding. A split caulk line lets water behind the frame.
• Screens. The screen frame is often vinyl too. Check the corners the same way, and look at the mesh for holes.
• Glass seal. On double-pane units, look for fogging or moisture between the panes after a few days of sun. Fog can appear weeks after a storm, so check again on a warm, dry afternoon.
• Weep holes. The small drainage openings at the bottom of the frame should be clear. Hail-driven grit can plug them, and a plugged weep hole holds water inside the frame.

How to photograph the frames

Take each photo in daylight with the sun at your back or to the side. Flash washes out the dent. Shoot one wide photo of the whole window so the location is clear, then one closer photo of each corner and the sill. Put a flat object of known size in the frame for scale, such as a tape measure laid along the sill. Keep the original files on your phone or camera and do not send screenshots, because screenshots lose the date data and the resolution that shows a hairline weld gap.

Write down which elevation each window faces. Hail on the windward side of a house is common in St. Louis storms, and the windows on the side facing the storm's path are the ones most likely to show damage. A simple list with the room, the side of the house and the date of the walk is enough. Dated photos and a short list are the kind of record a roofer or an insurer can read quickly.

What a contractor can and cannot do with a window finding

Keys Roofing documents storm damage on the roof and, when asked, on other parts of the house that the storm reached. Our crew photographs what it finds, measures what it can measure, and puts a written scope with photos and measurements in your hands. We attend as the contractor while you deal with your own insurer. The insurer decides what is covered under your policy.

Missouri law also sets a limit on what a roofing contractor may say about your claim. Under RSMo 407.725, a roofing contractor is barred from representing or negotiating a homeowner's insurance claim, and from saying anything about paying, waiving or covering a deductible. A contractor who offers to handle the claim for you, or to take care of the deductible, is stepping outside that law. The claim stays with you and your insurer, and the written scope is the document that goes with you to that conversation.

When to call

If a corner shows a gap, a split or a dent you can feel, or if a sill cap is lifted, call before the next freeze and before you finish the rest of the house walk. A window that is letting water in can be repaired or sealed in place, and the cost is usually lower than replacing a frame after a second winter. If you find fog between panes, note it and call once the glass has been checked on a dry day.

Keys Roofing can be reached at (314) 220-2333. Ask for a written scope that lists every window you want looked at, the side of the house each one faces, and the photos taken of each corner and sill. That list is the one thing you can take to your insurer without relying on anyone else's memory of the storm.