Radon
A radon barrier in a new extension is torn where a pipe passes and no reading was taken. What continuity of the barrier was not proved?
The continuity of the radon barrier was not proved at the pipe. The membrane in the new extension is torn where that pipe passes, and no reading was taken, so the survey has not shown an unbroken sheet and has not measured radon. A tear at a penetration is a gap in the barrier as seen. It is not a radon result. The inspection recorded the damage. It did not test the air and it did not repair the seal around the pipe.
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?
A radon barrier works only as a continuous sheet, closed at the laps and at every pipe that goes through it. A tear beside a pipe is the sort of gap that defeats the sheet at that point, even if the rest looks whole. The surveyor can see the tear. They cannot see the membrane under every finish, and they took no reading. Area maps are a separate source of information. They are not a measurement of this extension, and this visit did not supply one.
Ask the solicitor whether any radon report or barrier warranty exists for the extension, and tell them the sheet is torn at a pipe. If you want the barrier made continuous, that is a builder's detail at the penetration, not a design this survey has produced. Do not treat the lack of a reading as a low result. No test was done. The survey has not certified the membrane.
What should you ask your surveyor?
- Is the radon barrier torn where the pipe passes through it?
- Was any radon reading taken in the extension?
- Has continuity of the barrier at that pipe been left unproved?
What are the typical next steps?
- Treat the tear at the pipe as unproved continuity, not as a reading.
- Tell the solicitor the barrier is torn and no test was made.
- Do not read the absence of a figure as a low radon result.
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
If the rest of the sheet looks intact, is the barrier continuous?
Not at the pipe. Continuity means the whole sheet, including every penetration. The barrier is torn where the pipe passes, so that point was not proved continuous. The rest looking tidy does not close the tear. No reading was taken, so there is also no measurement to lean on.
Does a new extension automatically include a sound radon seal?
No. New work can still be torn at a pipe, which is what was seen here. The survey has not certified the barrier and has not taken a reading. Age of the extension is not a test. The continuity that matters in this note is the torn sheet at the pipe, and that was not proved.