Wall ties and cavity insulation

Can render stop a surveyor seeing wall-tie cracks that are still in the brick?

Yes. Render covers the bed joints where tie corrosion usually cracks the mortar. The surveyor then sees render cracks, hollow render, or nothing. They should not convert a rendered wall into a clear bill of health for the ties, and they should not declare tie failure without a pattern they can point at.

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 cavity wall behind render is still a cavity wall. Ties can corrode whether or not you can see the brick. What the survey can say is limited to the surface: map cracks, bulges, and stains. A borescope needs a hole. That is not part of a standard Level 2 unless you agreed it. The Energy Saving Trust also says walls should be in good condition before cavity insulation, which you cannot confirm through cracked render by guessing.

If the report says the wall is rendered and the ties were not assessed, that is a limit, not a defect and not a pass. Decide whether the house’s age and exposure justify a tie inspection. Do not pay to hack off all the render “just in case” before a specialist has said where they need to look.

What should you ask your surveyor?

Is the wall rendered on the exposed faces, and did that limit the inspection?
Is there a bulge or only hairline cracks in the render?
Would you need openings in the render before you could talk about ties?

What are the typical next steps?

Read “not assessed” as not assessed. Do not upgrade it to a failure in your offer letter.
If you commission a tie survey, agree how many openings and on which elevations.
Do not install cavity insulation through render that is already hollow.

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

Is cracked render always a tie problem?

No. Render cracks from shrinkage, movement of the coat, and leaks. Ties are one cause among others on cavity walls.

Should you remove render before exchange?

Not as a default. Removal is destructive. Ask the surveyor whether the decision needs it.