Service
Exterior Damp Specialists Fixing the Cause, Not the Stain in London & Kent
We trace penetrating damp back to the failed joint, render, sill or flaunching letting water in, repair the fabric properly, and stop the patch coming back next winter.
18 years diagnosing external walls · 10-year workmanship guarantee
- 18 years' experience
- £2m public liability insurance
- 10-year workmanship guarantee
- K Rend approved installer
- Listed on TrustATrader
What exterior damp work involves
Most damp on an external wall is water getting in from outside through a defect you can point at: receded mortar joints, cracked or hollow render, a failed chimney flaunching, a bridged or missing sill throating, a leaking gutter or downpipe, or render carried down to ground level. Our work is finding that defect and repairing the building fabric so the water stops arriving.
That is deliberately different from covering the symptom. Sealing a wall, re-plastering internally or painting over a stain does not remove water from the masonry, it hides it while the wall behind keeps getting wetter.
Because we repoint and render as our core trade, the diagnosis and the repair come from the same team. There is no handover between someone who identifies the fault and someone else who fixes it.
Who it is for and when to call
It is for owners with a damp patch on an internal wall that shows up or worsens after heavy rain, especially on the wind-facing elevation; for solid-wall period houses where cement pointing or cement render has trapped water; and for anyone who has already had a wall re-plastered and watched the patch return.
Call when you see: staining or blown plaster on an external-facing wall, salting or a tide mark, black mould concentrated in one area rather than throughout the room, a musty smell in one corner, or green algae in a vertical line outside where a downpipe is discharging onto the wall.
We work on period and conservation-area property across London and Kent. We do not take on listed buildings.
What happens if it is left
The cost of leaving it another winter
Damp does not hold steady. A wall that is repeatedly wet loses plaster, perishes decoration, corrodes embedded fixings and, over a longer period, puts embedded timbers, joist ends and lintels in older houses, at risk. Those are structural repairs, not decorating.
The masonry itself degrades too. Saturated brick that freezes spalls, and every spalled face is a bigger sponge than the one before it. What began as one joint letting water in becomes an elevation that needs brick replacement as well as repointing.
There is a health and comfort cost as well: persistent mould growth in one corner of a bedroom, and a room that is colder and harder to heat because wet masonry conducts heat out far faster than dry masonry does.
Common mistakes we are called in to undo
- Treating every damp patch as rising damp and injecting a chemical course, when the water is coming in through the wall above.
- Painting or sealing the outside of a solid wall with a waterproof coating, which locks existing moisture inside the masonry.
- Re-plastering internally before the external defect is fixed, so the new plaster fails and the money is spent twice.
- Ignoring rainwater goods, a single cracked downpipe collar will soak one strip of wall indefinitely.
Our process
How a exterior damp specialists job runs from first call to guarantee
Step 1
Inspection
We look at the wet area inside, then work the matching elevation outside, joints, render, sills, copings, flaunching, verges, rainwater goods and ground levels, rather than guessing from the internal stain.
Step 2
Diagnosis
We identify the route the water is taking and tell you plainly what is causing it. If the cause sits outside our trade, we say so instead of selling you repointing you do not need.
Step 3
Specified repair
You get a written fixed price for the specific repair, repointing in the right mortar, cutting out and rebuilding failed render, renewing flaunching, reinstating weathering details, with a payment schedule across the project.
Step 4
Execution and detailing
Access is arranged by us. The fabric repair is carried out in materials appropriate to the wall, with the weathering details that throw water clear reinstated properly rather than filled.
Step 5
Verification, drying and guarantee
We check the repair under wet conditions where we can, explain the drying period the wall needs before internal redecoration, and back the completed work with our 10-year workmanship guarantee.
What you get
The results this work is actually bought for
The patch stops coming back
Fixing the entry point is the only thing that ends the cycle of re-plastering and repainting the same wall.
You stop spending twice
Internal redecoration done after the external repair holds. Done before it, it is money you will spend again.
Your masonry stops degrading
Dry brick does not spall. Getting the wall dry protects the fabric you cannot easily replace.
A warmer, cheaper-to-heat room
Dry masonry insulates far better than saturated masonry, so the affected room stops feeling cold and clammy.
Mould loses its water supply
Remove the moisture source and the mould in that corner has nothing to grow on, no repeat treatments needed.
An honest diagnosis
If the cause is a gutter, a leaking pipe or condensation rather than the masonry, we tell you that. We would rather lose the job than sell the wrong one.
In detail
Exterior damp specialists: materials, methods and where it applies
Penetrating damp, rising damp and condensation
Penetrating damp comes through the wall from outside and tracks with the weather: worse after driving rain, worse on the exposed elevation, often at a specific height. Rising damp comes up from the ground and shows as a tide mark low on the wall with salting. Condensation is spread across cold surfaces, worst in winter, worst behind furniture and in corners, and it responds to ventilation rather than masonry work.
They get confused constantly, and the wrong diagnosis is expensive. Our work is external: where the evidence points to condensation or a plumbing leak, we will say so plainly rather than quote for pointing that will not change anything.
Common external causes we find
Receded or cracked mortar joints on the wind-facing elevation. Cement pointing on a soft-brick solid wall forcing evaporation through the brick face. Hollow or cracked render taking water in and holding it behind the skin. Render bridged down to ground level. Cracked chimney flaunching and open stack joints. Sills with no throating, or a bridged cavity at an opening. Blocked, cracked or misaligned gutters and downpipes. Raised patios and flowerbeds sitting above the damp-proof course.
On most jobs there is more than one contributor, which is why we survey the whole elevation rather than repairing the first fault we spot.
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Repair methods and materials
The material has to suit the wall. On pre-1919 solid walls that means breathable lime mortar and, where render is involved, a lime-based render, so the wall can dry outward. On modern cavity construction a cement or thin-coat specification is appropriate. Using a hard, impermeable material on a breathable wall is the cause of a large share of the damp problems we are called to.
Weathering details are rebuilt, not filled: drip and bell beads at the base of render, throated or repaired sills, sound flaunching and correctly bedded copings. Those details are what keep bulk water off the wall between now and the next repointing cycle.
Homes, flats and commercial buildings
In houses the scope is usually one elevation and its details. In flats and managed blocks the wet room and the defect are often on different levels and different ownerships, so the survey has to establish where the water actually enters before anyone is billed.
We cover London and Kent, including Bexley, Bexleyheath, Sidcup, Dartford, Erith, Bromley and Orpington, where exposure varies sharply between sheltered terraces and open, wind-driven elevations.
Not sure this is the right specification for your wall? See all of our services, the areas we cover, or go back to the homepage.
FAQs
Exterior damp specialists questions we are asked most
How much does fixing exterior damp cost?
It depends entirely on the cause, renewing a flaunching is a different job from repointing a full elevation. We diagnose first, then give you a written fixed price for the specific repair, with payments spread across the project. Quotes are free. Small jobs carry a minimum charge.
How quickly can you look at a damp problem?
Call 07360 597865 or email and we will arrange a visit. We do not publish a fixed response-time promise we cannot keep for every job, you will be given a real date.
How do I know whether it is penetrating damp or condensation?
Penetrating damp is localised, on an external wall, and worsens with rain. Condensation is spread across cold surfaces and corners and worsens in winter with poor ventilation. We assess it on site rather than from a photo alone.
Will repointing stop my damp?
It will if failed joints are the route the water is taking, which is common on exposed solid walls. It will not if the water is coming from a gutter, a leak or ground level, and we will tell you which it is.
How long will the wall take to dry out?
Masonry dries slowly, and a solid wall that has been wet for a long time can take months. We will tell you when it is sensible to redecorate internally so you are not painting a wet wall.
Is the work guaranteed?
Completed work carries a 10-year workmanship guarantee and we hold £2 million public liability insurance. We are listed on TrustATrader.
Should I use a waterproof sealer on the outside wall?
On a solid breathable wall, no. Sealers trap moisture already in the masonry and can make the problem worse. The correct fix is repairing the defect and letting the wall dry outward.
Do you do emergency call-outs?
We are contactable 8am to 5pm on 07360 597865. Urgent water ingress gets prioritised where our programme allows, but we will not promise a call-out window we cannot honour.
Do you work on listed buildings?
No. We work on period and conservation-area properties, but not listed buildings.
Related work
Often carried out alongside this
Hydraulic lime repointing
Breathable lime mortar joints for period and solid-wall brickwork, matched to the original pointing style.
Read moreRender repair & crack remediation
Cracked, hollow or blown render cut out, rebonded and blended back so the repair does not read as a patch.
Read moreChimney repointing
Stacks repointed, flaunching renewed and weathering details reinstated, with our own access arranged.
Read moreFree quote
Find out what is actually letting the water in
Describe the damp patch and when it appears, and send a photo inside and out if you can. We will inspect the elevation, tell you the cause and price the repair in writing, free.
- 18 years' experience
- £2m public liability insurance
- 10-year workmanship guarantee
- K Rend approved installer
- Listed on TrustATrader