Windows, doors and glazing
What should you ask if the silicone around a window has split while the frame stays square?
Ask about the sealant joint, not the frame as a whole. Silicone or mastic around a frame is a surface seal, and when it splits, rain can track into the gap even though the frame is still firm and square, which is not misted glass and not missing paperwork. A survey sees the split if it was in view, does not water-test the joint, and a fresh bead is not evidence the gap behind it is sound.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
Installers often finish a gap with a fillet because the opening was irregular. The fillet is the first thing to let go, especially on a south face or where the frame moves a little. The frame can be perfect. A home survey describes open sealant, staining under it, and whether the frame itself is loose. It cannot see the foam or the packers behind the fillet. Concealed parts are not proved. Do not write “failed window” when the sentence is “split perimeter seal, frame firm”.
Cutting out and resealing is maintenance. There is no RICS price. If the survey also found the frame loose in the opening, or rot in a timber subframe, that is a larger repair and should be quoted separately. Do not replace uPVC because the silicone has failed. Do not rely on a certificate to prove today’s seal: paper does not describe a joint that has since split. A dry day will not show the leak. Look for stains on the reveal, which are clues, not a hose test.
What should you ask your surveyor?
- Where has the sealant split, and is the frame firm behind it?
- Is there staining on the reveal?
- Are you separating this from misted glass and from paperwork?
What are the typical next steps?
- Price a reseal before you price a new frame, if the frame is firm.
- Do not skim fresh silicone over a failed fillet without cutting the old one out.
- Keep any rotten subframe as its own item if the survey found one.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
Is foam behind the frame a defect if you can see it?
Exposed foam means the finish seal is missing. The foam is not a weather seal. Say that it is exposed.
Does split sealant slump the lintel?
No. Movement over the window is a lintel or a bearing question. Do not blame a silicone joint for a crack in the brick unless the survey links them from what it saw.