Non-standard construction
Map cracking covers the render of a no-fines house and no core was taken. What of the concrete behind the map was not tested?
The concrete behind the map-cracked render was not tested. No core was taken, so the no-fines wall was not sampled and was not sent for any check. Map cracking is a network of cracks in the render coat. The survey has recorded that pattern on a no-fines house. It has not tested the concrete behind the coat, has not described the material inside the wall, and has not decided that the wall has lost strength. The coat and the concrete are different layers. A map on the render is not a test of the wall it covers.
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?
No-fines concrete is a non-standard wall, cast with coarse aggregate and little fine material, and these houses are often rendered. The render can craze in a map as it ages or loses grip, and that pattern can sit on concrete that is still working or on concrete that is not. Telling those apart needs a look at the concrete, which a core would start. No core was taken. The survey stayed on the surface it could see. The condition of the concrete is exactly what was not tested.
Tell the solicitor the house is no-fines, the render is map-cracked, and no core was taken. If a lender asks about the concrete, that question needs someone instructed to investigate it, not a rereading of the render. The home survey has not tested the wall and has not produced a materials result. Do not call the concrete sound because the cracks are in the coat, and do not call it failed because the map is widespread. Neither of those tests happened.
What should you ask your surveyor?
- Was the map cracking in the render, rather than in a tested concrete face?
- Did you record that no core was taken?
- Have you left the no-fines concrete untested?
What are the typical next steps?
- Treat the concrete behind the render as untested.
- Tell the solicitor no core was taken.
- Do not grade the no-fines wall from the map in the coat.
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 render sounds solid when tapped, is the concrete sound?
A tap, where one was made, speaks to the coat. It does not test the no-fines concrete, and no core was taken. The survey has not called the wall sound or unsound. Map cracking remains a render note. The concrete behind the coat stays untested whatever a tap suggested about the surface.
Does the map pattern name a particular prefabricated system?
Not by the cracks alone. The survey describes a no-fines house with map-cracked render. It has not used the map to assign a named prefabricated system, and it has not tested the concrete. If a lender needs the type, that needs the construction papers or a specialist. This report has not identified a system from the cracks.