DPC cost by scope of work
Typical costs from a PCA-registered specialist. Replastering is usually quoted separately.
| Scope | Method | Typical cost |
|---|---|---|
| Single short wall (up to 4 m) | Chemical injection | £300 to £500 |
| Single standard wall (4-8 m) | Chemical injection | £500 to £1,000 |
| Ground floor, 3-bed semi (all walls) | Chemical injection | £2,000 to £3,500 |
| Ground floor, detached house (all walls) | Chemical injection | £2,500 to £4,000 |
| Whole house (chemical injection) | Chemical injection | £2,500 to £4,500 |
| Electro-osmotic system (whole house) | Electronic/pulsed | £2,000 to £5,000 |
| Replastering affected walls (per room) | Sand and cement backing coat | £500 to £1,500 |
| Full ground-floor replastering | Salt-resistant plaster | £1,500 to £3,500 |
Prices are indicative UK averages for 2026. Listed buildings or solid stone walls may cost more.
Chemical injection vs electro-osmotic DPC
Chemical injection is by far the most common method. Specialists drill a series of holes 115 mm apart along the base of the wall and inject a silicone-based cream or fluid that cures to form a water-repellent barrier. The process typically takes one day per wall and has a long track record.
Electro-osmotic (or electro-osmosis) systems pass a low-level electrical current through the wall to reverse the polarity that draws moisture upwards. They suit solid stone, rubble-fill or mixed-material walls where injection is impractical. Pulsed systems are discreet, require no drilling of continuous holes, and are increasingly popular in listed buildings.
Neither method removes existing salt contamination from the plaster. That is why replastering with a salt-resistant render or renovation plaster is almost always recommended after a DPC is installed. Skipping the replaster and simply redeccorating over contaminated plaster is the single most common reason DPC treatments appear to fail.
What affects the cost
Several factors can push the final bill above or below the typical range:
- Wall length and height: longer or taller walls take more material and time.
- Wall construction: solid brick is straightforward; rubble-fill, stone or cavity walls are more complex.
- Access: restricted external access or internal fitting requirements add labour.
- Number of elevations: terraced houses may only need rear and front walls; detached homes need all four.
- Extent of replastering: damp-damaged plaster must be hacked off 300 mm above the visible tide mark and replaced with renovation plaster.
- Location: London and South East labour rates are typically 20-30% higher.
- Guarantee requirements: GPI (Guarantee Protection Insurance)-backed 30-year guarantees are standard from reputable firms.
Get an independent diagnosis before any work
Most reputable surveyors and the Property Care Association warn that rising damp is frequently misdiagnosed. Condensation, bridged external render and leaking gutters all mimic the symptoms. Instruct an independent PCA-qualified surveyor before accepting a specialist contractor's diagnosis and quote. Thousands of homeowners have paid for unnecessary DPC treatments.
How the DPC process works
What to expect from instruction to completion:
Independent survey
A PCA-qualified surveyor (not one employed by the contractor quoting for the work) inspects with a calibrated moisture meter and diagnoses the cause of dampness. Expect to pay £150-£300 for an independent report.
Obtain at least three quotes
Quotes should specify the method, number of walls, plaster specification, guarantee type (GPI-backed), and whether VAT is included. Compare like for like.
DPC installation
Holes are drilled and cream or fluid injected. The wall is usually left to cure for a minimum of 24-48 hours before replastering begins. The drilling itself is relatively fast, often a half-day per wall.
Hack off and replaster
All contaminated plaster is removed to at least 300 mm above the damp tide mark. A salt-resistant backing coat is applied, followed by a renovation plaster finish coat. Allow at least four to six weeks before decorating.
Guarantee and documentation
The contractor should issue a written guarantee, typically 20-30 years, backed by GPI or a similar insured scheme so the guarantee transfers if the contractor ceases trading.
Budget for the full cost before you buy
Our planner helps you set a realistic buying and refurbishment budget before you commit. Add DPC treatment, replastering and redecoration as separate line items so your reserve is accurate from the outset.