Damp Proofing & Tanking
Damp Proofing & Tanking in Cumbria
Damp is one of the most common faults in older Cumbrian property. We find the cause first, carry out the treatment, and put right the gutters, drains, pointing, plaster and joinery around it.
- Approved Sovereign installer
- 10, 20 or 30 year guarantees
- Diagnosis before treatment
- Our own joiners, bricklayers and plumbers
Why Ashcroft
One firm, from cause to finish
Driving rain off the Solway, solid stone walls, lime mortar and houses built long before damp-proof courses were standard all play a part. Get the diagnosis wrong and it is easy to spend good money on a treatment that does nothing.
The right diagnosis
A proper survey looks at the outside of the building first and rules out other causes before treating for rising damp.
All the trades
We employ our own joiners, bricklayers, plumbers and groundworkers. Read more about the business and our trades.
Care with old buildings
On solid stone walls, sorting out drainage, ground levels and lime pointing often achieves more than any injection.
Homes after flooding
Our teams have also worked on putting homes right after flooding, and you can read what some of those clients said on our testimonials page.
Approved Sovereign installer. Ashcroft is an approved Sovereign installer for tanking and timber treatment, with a choice of 10, 20 or 30 year Protection Scheme Guarantees for timber and damp proof courses. We explain what the guarantee covers before you commit to the work.
Start with the right diagnosis
Three causes, three different fixes
Damp in a building usually comes from one of three places, and each needs a different fix.
Rising damp
Ground moisture drawn up through the wall where there is no damp-proof course, or where it has failed or been bridged.
Penetrating damp
Water getting in from outside: failed pointing, cracked render, blocked or leaking gutters and downpipes, paths or soil built up against the wall, or debris bridging a cavity.
Condensation
Moisture from cooking, washing and drying clothes settling on cold surfaces. It needs ventilation, heating and insulation, not chemicals.
The classic mistake
Injecting a new damp-proof course into a wall that is actually wet from a leaking gutter or a raised flower bed. A proper survey:
- Looks at the outside of the building first.
- Checks ground levels against the internal floor.
- Treats moisture readings as a guide rather than a verdict, because salts in old plaster can give high meter readings on a wall that is no longer wet.
BS 6576, the code of practice for diagnosing rising damp and installing chemical damp-proof courses, makes the same point: rule out the other causes before treating for rising damp.
How it works
Treating rising damp
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Remove bridging
Clear anything bridging the existing damp-proof course, such as soil, paths or render taken down to ground level.
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Inject a new DPC
Inject a chemical damp-proof course into the mortar bed at the correct height.
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Replaster
Hack off salt-contaminated plaster, usually to around a metre or above the highest salt line, and replaster with a salt-resistant system. Leave the old plaster on and the salts keep drawing moisture out of the air.
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Give the wall time
Thick stone walls dry slowly; a common rule of thumb is about a month for every 25 mm of thickness.
Cellar and basement tanking
Protection below ground
Rooms below ground hold back soil moisture and sometimes water under pressure, so they are treated differently from walls above ground. The reference document is BS 8102:2022, the code of practice for protecting below-ground structures against water ingress. It sets out three types of protection.
Barrier protection
A tanking slurry, render or membrane bonded to the walls and floor to hold water out.
Structurally integral
The structure itself is watertight, usually designed-in concrete on new builds.
Drained protection
A cavity drain membrane lets any water that gets through run down behind it to a channel and sump, where it is pumped away.
Before you tank a cellar
- Higher-risk basements often combine two types.
- The level of dryness depends on what the room is for: a store or workshop can tolerate more than a bedroom or living room, which needs the driest grade, Grade 3.
- Drained systems with pumps need regular servicing, so ask for a maintenance plan with any Type C job.
- Turning a cellar into a habitable room usually needs Building Regulations approval for things like ventilation, insulation and escape. Around Maryport, Workington and Whitehaven that means Cumberland Council's building control team or a registered building control approver.
Also treated
Timber, older and listed buildings
Timber treatment
Damp and rot go together. Joist ends sitting in a wet wall, skirtings against damp plaster and timber lintels behind failed pointing are where wet rot starts. Dry rot is rarer but more serious, because it can spread through masonry to reach dry timber. Woodworm is a separate problem but often turns up in the same survey.
- Stop the moisture.
- Cut out and replace decayed timber.
- Treat what remains.
Older and listed buildings
Traditional solid stone walls with lime mortar manage moisture by letting it evaporate. Cement render, hard cement pointing and impermeable tanking can trap water in the wall and make things worse.
- Sorting out the drainage, lowering ground levels and repointing in lime often achieve more than any injection.
- If the building is listed, many damp treatments need listed building consent, so speak to the council's conservation officer before work starts.
FAQ
Frequently Asked Questions
How do I know if I have rising damp?
You cannot tell from a damp patch alone. Rising damp is less common than many people think, and condensation or penetrating damp can look very similar. A survey that checks the outside of the building, the ground levels and the pattern of moisture and salts is the only reliable way to tell.
What guarantee do you offer?
As an approved Sovereign installer we offer a choice of 10, 20 or 30 year Protection Scheme Guarantees for damp-proof courses and timber treatment. We explain what the guarantee covers before you commit to the work.
Can a cellar be tanked so it can be used as a bedroom?
Often, yes, but it needs a system designed for the driest grade, plus Building Regulations approval for ventilation, insulation and a safe means of escape. If a cellar is not suitable, we will say so.
Will I need to move out while the work is done?
Usually not. Damp-proof course injection and replastering are normally done a room or two at a time. It is dusty and noisy work, though, so rooms need emptying and furniture moving.
Do you work on listed buildings?
We will look at them, but the answer is often a gentler, breathable approach rather than chemicals and tanking. Listed building consent may be needed, and the owner must have it in place before work starts.
Damp walls, a musty cellar or rot in the floor?
Contact us with the address, the age of the property and a description of the problem. Photos help.