Damp-Proof Course (DPC) Injection
A damp-proof course is the barrier that stops moisture rising up through a wall from the ground. In older properties it can fail, break down or be bridged by raised paths and flower beds. DPC injection installs a new barrier by injecting a water-repellent cream into the mortar course, restoring protection without rebuilding the wall.
Quick answer
Damp-Proof Course (DPC) Injection typically starts from £350 — from £350 per treated wall, depending on length and access. We confirm a fixed written price after a survey, before any work starts.
What dpc injection involves
The cream is injected at regular intervals along a single mortar bed and diffuses along it, curing into a continuous water-repellent layer. It's a clean, targeted method that works on brick and most masonry, and it's the standard modern approach to a failed damp-proof course — far less disruptive than physically cutting a new membrane into the wall.
DPC injection is the core of most rising damp treatment, and it's rarely done on its own — the salt-contaminated plaster above the old damp line usually has to come off and be replaced with a salt-resistant system as part of the same job, which is where damp-proof re-plastering comes in. We always start with a damp survey to confirm the damp-proof course really has failed, because bridging (a raised path, render over the DPC, or debris in a cavity) sometimes causes the same symptoms and is fixed differently.
What's included in every dpc injection job
- ✓Water-repellent cream injected into the mortar bed
- ✓Suitable for brick and most masonry walls
- ✓Minimal disruption compared to physical DPC replacement
- ✓Paired with re-plastering and backed by a written guarantee
Get a survey for dpc injection
Book a Free SurveyWhatsApp +44 7415 016237Check if we cover your area →When you might need dpc injection
The most common situations we're called out for — if yours isn't listed, send a couple of photos through the contact form and we'll tell you exactly how we'd handle it.
A failed or missing DPC
Older properties where the original damp-proof course has broken down or was never installed.
Bridged damp course
Raised ground, paths or render that let moisture bypass the existing barrier.
After an extension or alteration
Where new and old walls meet and the damp-proof course needs to be made continuous.
How It Works
- 1
Book a free damp survey
Tell us what you’re seeing — a tide mark, black mould, blown plaster or a survey that flagged damp. We arrange a visit, usually within a few days.
- 2
We diagnose the real cause
On site we identify whether it’s rising, penetrating or condensation damp (they’re treated completely differently) and give you a clear, honest explanation.
- 3
You get a fixed written quote
A clear, itemised price for the recommended work — no pressure, no vague estimates that move on the day, and no charge for the survey on standard jobs.
- 4
We treat it and guarantee it
The work is carried out to industry standards, the area is left clean and ready to redecorate, and the treatment is backed by a written workmanship guarantee.
Damp Proofing Price Guide
Indicative pricing — every job gets a fixed, written quote after a survey. No hidden extras.
Damp survey & report
diagnosis
Free
Free for straightforward jobs; a detailed independent survey report is available for mortgage or purchase cases.
DPC injection (per wall)
rising damp
from £350
Chemical damp-proof course injection to a single affected wall — priced by length and access.
Damp-proof re-plaster
per room
from £600
Salt-resistant re-plastering after treatment, so the wall can be redecorated cleanly.
Basement / cellar tanking
waterproofing
from £1500
Structural waterproofing (tanking or cavity membrane) — quoted per project after survey.
Often needed alongside dpc injection
Damp problems rarely come alone — these related treatments are commonly part of the same job, for example rising damp treatment, damp-proof re-plastering and damp surveys & reports.
Where we cover dpc injection
We provide damp-proof course (dpc) injection right across England, Wales and Scotland as part of our regular damp proofing coverage, including busy counties such as Greater London, Greater Manchester, Kent, Devon, Staffordshire, West Midlands, Hampshire and Merseyside. Not sure if we reach you? Check the full areas we cover or just send your postcode with your enquiry.
DPC Injection — frequently asked questions
What is a damp-proof course (DPC)?
A DPC is a barrier that stops ground moisture rising up through a wall. Older properties may have a failed or missing one; we install a new chemical DPC by injecting a water-repellent cream into the mortar course, which cures to form a continuous barrier.
How do I know if I have rising damp or condensation?
They're often confused. Rising damp shows as a tide mark up to about a metre on ground-floor walls, sometimes with salt staining; condensation shows as black mould in corners, around windows and in poorly ventilated rooms. A survey confirms which it is — the treatment is completely different, so getting the diagnosis right first matters.
Do I need to re-plaster after damp treatment?
Usually, yes. Rising damp carries salts into the plaster that keep drawing moisture even after the DPC is in, so the affected plaster is removed and replaced with a salt-resistant system. This is what lets the wall dry out and be redecorated without the problem coming back through.
Is your damp proofing work guaranteed?
Yes — damp-proof course treatments are carried out to industry standards and backed by a written workmanship guarantee. We confirm the exact terms and length in your quote before any work starts.
Damp is treated by cause, not by symptom: rising, penetrating and condensation damp look similar but need completely different treatments, which is why every job starts with a proper survey and diagnosis before any work is quoted.
Book a free survey for dpc injection
Tell us about the damp and your postcode — we'll arrange a survey and a fixed written quote.