Damp and moisture meters
The header-tank overflow drips into the eaves void instead of through an outside wall. What might that wet that has not been opened up?
Because the header-tank overflow drips into the eaves void, it might be wetting timber or insulation that has not been opened up. The survey can record the drip going into that closed space instead of through an outside wall. It has not lifted the ceiling, opened the void, or diagnosed rot. What might be wet is the eaves timber, the wall plate and any insulation lying there, none of which was exposed. Ask a builder or plumber to trace the drip once access is agreed. Do not treat an unopened void as a proved outbreak of decay.
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?
An overflow should discharge where the warning is obvious, usually through an outside wall. Here it drips into the eaves void, so the water goes where you cannot watch it. The void can hold rafter feet, a wall plate and insulation. Those are the parts that might be getting wet. The survey has not opened them, so it cannot say they are decayed, and it cannot say they are dry. The finding is the path of the drip, not a timber report on hidden wood.
Have the overflow rerouted to a visible outside discharge once you can instruct the work, and ask someone to look into the eaves void where the drip has been landing. Do not pull insulation out on a viewing. If the survey stopped at the hatch, say so, so nobody later claims the wall plate was inspected. A proper look at the unopened void is the next step. Until then the wet risk stays a risk, not a measured repair.
What should you ask your surveyor?
- Did you see the overflow actually dripping, or only a pipe aimed into the eaves void?
- How much of that void could you see from the hatch, if any?
- Was there staining on visible timber, separate from the parts still closed?
What are the typical next steps?
- Treat the drip as a path into an unopened eaves void.
- Ask for the overflow to discharge outside where it can be seen.
- Do not open the eaves or pull insulation out on a viewing.
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
Does a drip into the eaves mean the roof covering has failed?
No. This note is the header-tank overflow discharging inside the void. It is not a finding that the tiles or slates have failed.
If the loft felt dry at the hatch, is the eaves timber clear?
No. Dry boarding by the hatch is not the closed eaves. The survey has not opened the place the overflow actually drips into.