Wall ties and cavity insulation

What should you ask if cavity insulation was installed on the front elevation only?

Ask why only that face was filled, and what the surveyor could actually see on the other faces. Fill on the front is not proof the ties there were checked, and an empty side or rear wall is not proof those walls failed a test. The home survey did not boroscope any of them. Each elevation still needs its own sentence.

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?

Owners sometimes fill the street elevation and leave the rest, or they only drill the wall they can reach from a path. The pattern of holes tells you where someone injected. It does not tell you the cavity is clear, that the two leaves are properly tied, or that the unfilled walls are unsuitable. The Energy Saving Trust’s advice is about suitable cavities and sound masonry, not about treating one drilled elevation as a certificate for the whole house. A home survey records the pattern. It does not repeat the installer’s inspection, because it was not there when the holes were drilled.

Do not ask the seller to fill the remaining walls as though the survey had specified it, and do not refuse the house only because the back is still empty. Empty is how many of these walls were built. Ask whether any elevation has cracks, bulges or spilled fill, and keep that separate from the fact of a front-only grid. If a lender or an insurer asks whether the cavity is insulated, the honest answer is “the front appears filled; the other walls were not described as filled”. That is the whole of what this visit established.

What should you ask your surveyor?

Which elevations have a fill pattern, and which do not?
Did you see defects on the filled wall, the unfilled walls, or neither?
Are you treating front-only fill as a problem, or only recording where the holes are?

What are the typical next steps?

Describe each elevation separately to any insulation firm.
Do not assume the unfilled walls must be injected because the front was.
Do not assume the front ties are sound because the front was drilled.

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 front-only fill cause damp on the unfilled walls?

The survey cannot say that from the pattern of holes. Damp needs its own evidence. Ask what staining, if any, was seen.

Should the guarantee cover the whole house?

Only if the job was the whole house. Read the paperwork. A front-only guarantee does not describe the rear wall.