Cavity wall tie replacement

Wall ties hold the brick outer leaf to the inner wall. Older steel ties rust, and rust swells: the mortar joints crack and the brickwork can bow. Wet cavity fill speeds that up, which is why tie problems so often turn up when insulation is being taken out.

About £30 to £50 per m² of wall

Guide prices checked November 2026, for England, Scotland and Wales.

Ask for a wall tie survey

Signs the ties may need attention

Horizontal cracks in mortar joints, repeating every sixth course or so, often clearest on the weather side.
Bulging or bowing brickwork, or a gap opening where the outer leaf meets window frames.
A house built before about 1980, when galvanised steel ties with thin coatings were common.
Wet fill found in the survey. Water sitting against ties for years is exactly what corrodes them.

Wall tie prices

Item	What it covers	Guide price
Wall tie survey	Metal detector and borescope, written report	£250 to £450
Remedial ties	Stainless steel, per m² of wall treated	£30 to £50
Semi-detached, all walls	About 80 m²	£2,400 to £4,000
Isolating old ties	Where corroding ties must be cut or removed	Priced on survey

Guide prices before VAT from a national trade price guide (price table May 2024), read November 2026. Many jobs only need the worst elevation done. Work out your own house.

If ties need doing, it is cheaper while the cavity is already open. Ask for both in one survey.

Ask for a wall tie survey

How remedial ties are fitted

Remedial ties are stainless steel and fitted from outside. A hole is drilled through the outer leaf, across the cavity and into the inner wall, and the tie is fixed either mechanically (it expands as it is tightened) or with resin. The hole in the brick face is then filled to match. Ties go in at a set spacing across the wall, closer near openings and edges.

Where old ties are badly corroded and have pushed the brickwork, they may also need isolating or cutting out so they cannot keep expanding. That is more work and is priced on survey.

Why this belongs with extraction

The borescope used in an extraction survey shows tie condition at the same time.
With the cavity empty it is easier to see each tie and confirm new ones are fitted correctly.
Historic England advises that wall tie corrosion must be dealt with before a cavity is insulated, because insulation makes it worse.

When a lender asks for a wall tie report

Valuers who see the crack pattern sometimes make a mortgage offer conditional on a tie report. That report usually comes from the same kind of borescope and metal detector inspection, written up with photographs.

Where our information comes from

Prices are typical ranges from published UK contractor and trade price guides, read November 2026, before VAT. Guidance is summarised in our own words; it is general information, not advice on your particular house.

How the job gets done

Wall tie work is outside work, usually a day or two for a typical house.

Locate and inspect
Metal detector finds the ties, borescope checks their state.
Decide the extent
One elevation or all, and whether old ties need isolating.
Fit new ties
Stainless remedial ties drilled and fixed through both leaves.
Make good
Holes filled to match and cracked joints repointed.

Questions homeowners ask

How much does cavity wall tie replacement cost?

Published guides put it at about £30 to £50 per m² of wall, plus £250 to £450 for a survey. A whole semi-detached house is roughly £2,400 to £4,000 before VAT.

Can wet cavity insulation damage wall ties?

Yes. Old steel ties corrode faster when wet fill holds water against them for years.

Do all the ties need replacing?

Often only the worst elevation, usually the one facing the weather. The survey decides.

Can wall ties be replaced without removing the insulation?

New ties can be fitted through a filled cavity, but if the fill is wet or failing the cause is still there. Doing both together is usually better value.

Is wall tie failure covered by a cavity insulation guarantee?

Usually not in itself, unless it was caused by a defect in the insulation. Check the wording of your guarantee.

Keep reading

Cavity survey
Ties and insulation checked together.
Extraction
Clear the cavity first.
Mortgage valuer flagged it
When a lender wants a report.

Tell us what the walls are doing

Three short steps. Your postcode, the house and what you are seeing are enough to start. The specialist confirms the detail with a borescope survey before any price is fixed.

Costs you nothing. We hold on to what you send until you have agreed to the extraction specialist we suggest.

Step 1 of 3

Where is the house?

Postcode