Non-standard construction

What is a Cornish unit house?

A Cornish unit is a named precast concrete house type used after the war. The useful point for a buyer is that it is a PRC system, not that the name itself is a condition rating. The survey should say what it could see of the panels and the roof, and what a lining stopped it seeing.

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?

Lenders have their own criteria for named systems. Some want evidence of a particular repair. Some will not lend. Some will. The only way to know is to ask the lender with the address and the construction in the surveyor’s words. A blog that says “Cornish units are unmortgageable” is not your offer.

A Level 3 is the survey RICS describes for unusual construction. It still will not produce a repair certificate that was never issued. Ask the seller for papers. Ask the surveyor whether the concrete looks repaired or original, and what they could not see. Structural repairs, if a specialist later recommends them, are priced by that specialist.

What should you ask your surveyor?

Are you identifying a Cornish unit, or only concrete panels of some kind?
What would a Level 3 add that this inspection did not cover?
Which defects are about condition, as distinct from the name of the system?

What are the typical next steps?

Ask the lender now, with the survey wording.
Collect any repair certificates before you discuss price.
Do not walk away on the name alone, and do not ignore cracked concrete because the name feels familiar.

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

Are all concrete semis Cornish units?

No. Several named systems exist. If the surveyor is not sure of the name, they should say “precast concrete of a type I could not confirm”. That honesty is more useful than a wrong label.

Can you insure a Cornish unit?

Ask the insurer. Like lenders, they have their own rules. The survey is not an insurance quotation.