Windows, doors and glazing
A bow window has spread at the cill and the brick piers either side are upright. Why is that spread a window question before it is foundation movement?
The spread is a window question first because the bow has opened at the cill while the brick piers either side stay upright. A bow relies on the cill and the frame to hold the curve. When those give way, the window splays without the neighbouring masonry rotating. The survey has seen spread at the cill and upright piers. It has not exposed the foundations, and it has not called this foundation movement.
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?
Foundation movement would usually show in the walls as well as in one window: tapered cracks, a pier out of plumb, distortion shared with the masonry. Here the piers either side are upright, which points away from the wall rotating and toward the bow itself. Cills rot, joints open and the curved head loses its tie. That is joinery. The survey did not dig beside the bay, and an upright pier is not a foundation inspection. It is a reason not to start with the footings.
Ask a joiner who understands bow windows to look at the cill, the joints and how the frame is tied, before anyone specifies foundation work. Tell the solicitor the report has not diagnosed foundation movement from this spread. If other cracks in the house suggest movement, keep them as their own notes. This finding is the window, and the piers beside it were upright.
What should you ask your surveyor?
- Has the bow spread at the cill while the brick piers stay upright?
- Did you leave the foundations unexposed?
- Are you treating this as a window defect rather than foundation movement?
What are the typical next steps?
- Treat the spread as a bow-window question first.
- Ask a joiner to look at the cill and the frame ties.
- Do not write the upright piers up as foundation movement.
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Also asked about this
If the cill is rotten, has the footing dropped?
Rot in a cill is timber decay in the window. It is not a dropped footing. The piers either side were upright, and the survey did not expose the foundations. A soft cill explains spread in the bow without moving the wall.
Could the piers still be hiding movement?
They could only in the sense that foundations were not exposed. What the survey did see is upright piers and spread at the cill. That pattern is why the window comes first. Hidden footings were not inspected, and they were not blamed.