A proper damp diagnosis before a single product is specified, followed by a Delta-registered cavity drainage or barrier system that carries a 25-year waterproofing warranty. No paint-and-hope surveys.
Delta Registered Installers · 25-year waterproofing warranty · Free damp survey and written report.
Damp in a London basement is rarely one thing. It's usually a combination: rising damp from the ground, penetrating damp through the walls, condensation from poor ventilation, or a failed previous waterproofing job. Treating the symptom without diagnosing the cause guarantees the problem returns. We survey first, then specify.
A structured survey of damp presentation, moisture readings and ventilation performance, followed by a specified remedial system: cavity drainage, barrier tanking, ventilation upgrade or a combination, designed to BS 8102 and installed by Delta Registered Installers.
Homeowners with an existing basement or cellar showing damp signs, buyers or sellers where the surveyor has flagged damp evidence, and property owners whose previous waterproofing has failed.
At the first sign of damp: musty smell, tide marks, salts on plaster, mould in corners, cold spots on walls, or a surveyor's report flagging damp.
Damp untreated damages every finish it touches, affects air quality and blocks sale. Damp treated with the wrong system fails again within months. Only proper diagnosis and specification gives a permanent solution.
Every UHM project runs through the same structured stages. You'll always know what's happening next, who's doing it and when it completes.
A director surveys the basement, takes moisture readings, checks ventilation and identifies the source or sources of damp.
A written report with the diagnosis, recommended system and specification to BS 8102, before you commit to any works.
Delta cavity drainage, Type A tanking, ventilation upgrade or hybrid installed by our directly-employed, Delta-trained crew.
MVHR or extract designed and commissioned. Sump-and-pump tested with alarm and back-up. Documented results.
25-year waterproofing warranty, commissioning report and annual maintenance schedule handed over.
Basement damp comes in recognisable types. Each has a proven remedial approach. Here's the toolkit we work with.
Moisture drawn up from the ground through masonry by capillary action. Presents as tide marks on lower walls and salt deposits on plaster. Solved by cavity drainage or, on select walls, chemical damp-proof course installation combined with breathable finishes.
Moisture pushing through walls from ground contact or defective external detailing. Presents as patch damp on lower walls, sometimes with visible efflorescence. Solved with Delta cavity drainage (Type C), external drainage improvements or Type A barrier tanking depending on the situation.
Warm, humid air meeting cold surfaces below dew point. Presents as mould in corners, on wardrobe walls and behind furniture. Solved with mechanical ventilation (MVHR), insulation upgrades and, where necessary, humidity-controlled extract.
A previous cavity-drainage or tanking system that has failed. We survey the existing installation, identify the failure mode (pump failure, drainage blockage, membrane damage, wrong system for the risk class) and specify remedy, often extending or replacing the existing system rather than starting over.
We won't quote you a system before we've surveyed the source. Anyone who does is selling, not solving.
As Delta Registered Installers, our finished damp-proofing work carries a documented 25-year warranty.
The same directly-employed team installs everything from the sump to the plastering, no handover gaps.
Most damp surveys booked within a few working days. Reports usually delivered inside a week of the visit.
Written diagnosis, specification, commissioning report and warranty certificate, exactly what buyers' surveyors and lenders ask for.
A properly de-damped basement doesn't just look right: it smells right, sounds right and lives right.
Damp doesn't stabilise. It progresses through finishes, joinery, floors and eventually structure. What was a £2,000 remedial job becomes a £20,000 strip-out. And the impact on how the room feels is immediate.
Skirtings rot. Plaster salts. Floor coverings lift. Wardrobes bow. Every finish above the damp line becomes disposable, and every strip-out costs more than the original fix.
Sustained damp creates airborne mould spores. It affects sleep, respiratory health and the way children use lower-floor rooms.
Buyer's surveyors flag basement damp aggressively. A missing waterproofing warranty triggers retention on the sale price, or worse, the buyer walks.
Painting damp-proof paint over damp brick, the industry's most-sold placebo.
Injecting a damp-proof course as a universal answer to every damp problem.
Ignoring ventilation and treating only the walls.
Accepting a diagnosis from someone selling a specific product.
Installing cavity drainage without a maintained sump-and-pump.
Skipping the commissioning report, no report means no meaningful warranty.
Straight answers we give on almost every free site visit, cost, timeline, guarantees and what's included.
Priced per project. The number depends on the cause and scale of the damp, the system specified and the state of existing finishes. Site visits and written specifications are always free.
A cellar-scale cavity drainage installation typically completes in three to six weeks. Isolated damp remediation is shorter; full-basement systems take longer. Programme is confirmed in the written quote.
Almost never. Paints and coatings applied to damp masonry trap moisture and delay the symptom rather than solve it. We won't specify a paint job when a system is needed.
That's what the survey is for. Rising, penetrating and condensation damp look similar to the untrained eye but need different solutions. A proper diagnosis prevents you paying twice.
Yes. Delta-registered installations carry a 25-year waterproofing warranty. Chemical DPCs and specific product treatments carry manufacturer-backed guarantees, all documented at handover.
Usually, in the areas being treated. Cavity drainage requires access to the wall face, and plastering is done fresh over the new membrane. We sequence works to minimise disruption elsewhere in the home.
Almost always, if the basement is habitable. Mechanical ventilation with heat recovery (MVHR) manages humidity properly. We specify it alongside the damp system, not as an afterthought.
Yes, £10M all-risks insurance covering public and employers' liability. Documentation available on request.
A director will survey your basement, take moisture readings and give you a written diagnosis and quote, for free. If the answer is 'do nothing yet', we'll say so.
