Windows, doors and glazing
What should you ask if a new door threshold sits below the outside paving?
Ask whether rain can run in over the threshold and whether the paving now bridges the damp-proof course. A door that is lower than the patio is a water path. It is not, by itself, a failed damp-proof course in the wall, and it is not a flood-map result. A home survey sees the levels. It does not redesign the step.
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?
People fit flush thresholds for access and then wonder why the hall carpet is wet. The surveyor should say if the outside ground is higher than the internal floor or the damp-proof course. The repair may be a drain channel, a revised threshold, or both. An injected damp-proof course does not raise the door.
There is no RICS price for that alteration. If the rating says water is entering, get a quote that names the threshold and the paving. Do not accept a whole-house damp treatment for one door. Approved Document M and access rules, if someone cites them, are about building work. They are not a pass for a wet hall.
What should you ask your surveyor?
- Is the outside paving higher than the threshold or the damp-proof course?
- Is the carpet wet, or is this only a level you measured by eye?
- Are you recommending drainage at the door, or a damp-proof course?
What are the typical next steps?
- Photograph the threshold and the paving on the same picture.
- Quote the door and the channel, not an injection.
- Do not lower the internal floor to match a high patio.
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 a level threshold always a defect?
No. It can be a proper accessible detail with a drain. The defect is water coming in, or levels that make that likely, not the word level.
Does a weather bar cure a high patio?
A bar on the door stops some driven rain. It does not fix paving that is higher than the floor.