Can a Cracked Window Be Repaired, or Does It Need Replacing?
A crack in window glass can’t be truly repaired; resin kits only hide a small crack for a while. The lasting fix is new glass, but in most cases only the glass is replaced, in the frame you already have, not the whole window. On double pane windows a crack also breaks the seal, so the sealed glass unit is replaced. Here is how to read the crack, what to do today, and when a whole new window makes more sense.
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Reading the crack
Where the crack starts and what it looks like tells you why it happened, and how fast it will grow.
Starts at the edge, no impact point
A stress crack, usually from heat or cold pulling on the glass, or a frame pressing on it. These tend to run across the pane over days or weeks.
Starburst from one point
An impact, such as a ball, a stone from a mower or a bird. The pane is weakened around the point and can break further when the window is moved.
The insulating seal is broken, so the unit will fog and lose its insulation. The whole sealed unit is replaced, not one sheet.
The simplest fix. New glass is cut to size and set in the existing sash, often the same day.
Do crack repair kits work on windows?
Resin kits are made for small chips in car windshields, which are laminated glass. Window glass is usually a single sheet or a sealed double pane unit, so the resin can’t bond the crack back together or restore the seal. At best it slows a short crack and makes it harder to see. The glass is still weaker, and a cracked double pane unit will still lose its gas and fog up.
Tempered glass, used in doors and next to tubs and floors, can’t be repaired at all. It doesn’t crack slowly; it breaks into small pieces.
What to do until it is fixed
- Don’t open or close the window more than you have to. Movement makes the crack run.
- Tape both sides with clear packing tape along the crack to hold the glass together and keep water out.
- Keep heat off the glass. Close blinds on sunny days and keep heaters and lamps away from the pane.
- Take photos of the crack and anything that caused it, for your records or your insurer.
- If there is a hole or the glass is loose, keep people away and call for emergency board up.
New glass or a new window?
The frame is solid, the window opens and locks, and only the glass is damaged. This is the usual case, and it costs far less than a new window.
Worn balances, broken locks or a sash that sticks can be fixed while the glass is out.
The frame is rotted or warped, several panes are failing, or you want better efficiency than the old frame can hold.
Insurance may help when the crack came from a storm, hail or a break in. The Triple-I explains what a standard homeowners policy covers, and notes that routine wear and tear is not included. Check your deductible first; for one pane of glass it is often more than the repair.
Cracked window questions
More questions? Browse our glass repair FAQ or contact us.
Can a cracked window be repaired?
Not in a lasting way. A resin kit can hide a small crack for a while, but the fix that lasts is new glass, usually set in the existing frame.
Do I need a new window if the glass is cracked?
Usually not. If the frame is in good shape, only the glass or the sealed glass unit is replaced, which costs much less than a new window.
Can one pane of a double pane window be replaced?
The two panes are sealed together as one unit, so the whole unit is replaced. It is made to fit your existing frame.
Is a cracked window dangerous?
A small crack is not an emergency, but it can spread and the glass is weaker. If there is a hole, or the glass is loose or in a door, keep people away and have it replaced soon.
Why did my window crack with nothing hitting it?
Most often it is a stress crack from heat or cold, or from a frame or hardware pressing on the glass. These usually start at the edge.
Cracked window?
Send a photo of the crack, or call (202) 600-6220 for a free estimate.