Age and type of house
A Victorian rear wing is single-skin brick. Has that wing been treated as if it were the cavity-walled main house?
No. The Victorian rear wing has not been treated as if it were the cavity-walled main house. The report records single-skin brick, which is a different wall: one leaf, with no cavity to drain or to insulate in the way the main house might. Approved Document A is structural guidance for building work, and this survey does not issue a building-regulations certificate. The wing stays described as it was seen, not redesigned as the front wall.
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?
Rear wings on Victorian terraces were often added in thinner brick than the main frontage. They wet through more readily, they have no cavity tray because they have no cavity, and their strength is not the strength of the main wall. Treating them as the same construction leads people to specify cavity details that cannot exist there. The survey’s job is to keep the two constructions apart. A visual note of single-skin brick does that. It does not calculate the wing or approve alterations to it.
If you plan work to that wing, ask the solicitor what papers exist and take the single-skin description to whoever designs the work. Approved Document A does not get issued by this survey, and the visit did not open the wall to prove every course. A lender may ask how the wing is built if it is relying on the house as standard cavity construction. Point them at the report’s distinction rather than at a guess.
What should you ask your surveyor?
- Which walls are described as the single-skin rear wing?
- How is the main house construction described beside it?
- Does any sentence treat the wing as cavity wall?
What are the typical next steps?
- Keep the rear wing described as single-skin brick.
- Do not specify cavity details for a wall with no cavity.
- Take the construction note to anyone designing work.
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 render on the wing create a cavity behind it?
No. Render is a coating on the face. It does not turn single-skin brick into the cavity-walled main house, and the survey did not find a cavity in the wing. The report records the construction it could see. Approved Document A is guidance for building work, not a reclassification written on this visit.
Was the wing opened up to count the brick leaves?
No. The wing was not opened up. Single-skin brick is what could be read from the thickness, the reveals or the construction the surveyor could see. That is a visual note, not a certificate. The survey has not treated the wing as the main house, and it has not measured every leaf by demolition.