Liquid Waterproofing Contractors

Liquid Applied Waterproofing Specialists

Liquid applied waterproofing is exactly what it sounds like: a membrane applied as a liquid — by roller, brush or spray — that cures on the structure into a seamless, fully bonded, elastomeric waterproof layer. Because it is cold-applied and forms in place, it follows the geometry of the structure precisely, wrapping upstands, movement joints, drainage outlets, pipe penetrations, balustrade posts and column bases in a single continuous membrane with no welds, laps or seams to fail.

That is why liquid systems dominate on complex structural decks. Sheet membranes are efficient across large, flat, uninterrupted areas, but every detail on a sheet system is a cut, a lap and a weld — and details are where waterproofing fails. On a car park deck with hundreds of penetrations, or a podium slab crossed by upstands and planters, a liquid membrane eliminates those weak points at source.

MPS Concrete Solutions installs liquid applied waterproofing on structures: car park decks, podium slabs, balconies and walkways, basements and below-ground assets, plant rooms and water-retaining structures. We waterproof structures, not just roofs — if you have searched "liquid waterproofing" and found only roofing firms, this is the page for the deck, podium or basement you actually need protecting.

Because the membrane is fully bonded to the substrate, water cannot track laterally beneath a liquid system. If the membrane is ever damaged, the leak appears where the damage is — making inspection and repair straightforward — and a localised patch restores a seamless membrane without stripping the whole area. Contrast that with an unbonded or partially bonded sheet system, where water entering through a single defect can travel metres beneath the membrane before it shows inside the building, and the true point of entry can take days of investigation to find.

Liquid membranes are also genuinely elastomeric: the cured film stretches and recovers as the structure moves through thermal cycles and live loading, bridging hairline cracks that open and close in the deck beneath. On a reinforced concrete structure that will crack — and every reinforced concrete structure cracks — that crack-bridging capability is what keeps the waterproofing intact for decades rather than seasons.

We work for property managers and residents' management companies, main contractors, structural engineers and building surveyors, local authorities and facilities teams — sometimes on a new-build package, more often on refurbishment, where an original membrane has reached the end of its life and water is already finding its way into the structure or the space below. In either case the sequence is the same: survey and diagnosis first, then a written specification, then installation by our own trained operatives under manufacturer inspection where a system guarantee requires it.

• Sika-approved contractors — manufacturer-backed systems with meaningful guarantees.
• 25+ years combined experience in structural waterproofing and concrete repair.
• BS 8102:2022 compliant design for below-ground and buried waterproofing.
• Free site survey and a fixed, itemised quotation before any work begins.

Where We Use Liquid Waterproofing

Liquid membranes earn their keep wherever the geometry is complex, the structure moves, or the deck stays in use during the works. These are the six applications where we install liquid applied systems week in, week out:

Across all of these applications the constant is that the waterproofing protects something expensive: the reinforced concrete structure itself, and the space or asset beneath it. Water and chlorides reaching embedded reinforcement start a corrosion cycle that ends in spalling, delamination and structural repair bills many times the cost of the membrane that would have prevented them. Waterproofing a deck properly is the cheapest structural maintenance you will ever buy.

Liquid Waterproofing Systems

No single chemistry wins everywhere. We are approved installers for the major manufacturers and specify the system to the structure, the exposure and the programme. A complete liquid waterproofing specification is a build-up, not a single coat: substrate preparation and repair, primer matched to the substrate, the waterproofing membrane itself — locally reinforced with fleece or scrim at joints, cracks and details — and, on trafficked areas, an aggregate-dressed wear course and top coat. Getting each layer right, at the right film thickness, is what separates a 20-year membrane from a 2-year callback.

Polyurethane (PU) Systems

The workhorse of liquid waterproofing. Single or two-component elastomeric membranes with excellent crack-bridging, UV stability and durability — the default choice for exposed balconies, walkways, podium decks and exposed slab edges. PU systems build into full trafficked deck specifications with wear courses for pedestrian and vehicular use.

PMMA Fast-Cure Systems

Polymethyl methacrylate resins cure in 1–2 hours even at temperatures near 0°C, which makes them the system of choice for winter application, live car park decks and any programme where downtime is the enemy. A deck bay coated in the morning can carry traffic the same day. PMMA carries a cost premium, but on a phased live-site programme it usually pays for itself in reduced disruption.

Cold-Applied Bitumen-Based Systems

Liquid bitumen and hybrid bituminous membranes offer robust, economical waterproofing for buried applications — podium decks beneath landscaping, below-ground walls and protected structures where UV exposure is not a factor and budgets matter.

Cementitious Slurry Systems

Polymer-modified cementitious coatings bond tenaciously to damp concrete and masonry, making them ideal for basements, water-retaining structures, tanks and bunds — including negative-side application where access to the wet face is impossible.

How We Install

Every installation starts with preparation, because liquid membranes are only as good as the surface they bond to. We mechanically prepare the substrate — captive shot blasting or diamond grinding on decks — repair spalled or cracked concrete first, confirm moisture content and pull-off strength, then prime and detail before the main membrane goes down. Wet film thickness is checked as we work and documented for the guarantee. On live sites we phase the works bay by bay or zone by zone, handing each area back as it cures, so car parks stay open and residents keep access to balconies and walkways throughout.

How Much Does Liquid Waterproofing Cost?

The question we are asked most often — how much do liquid waterproofing companies cost? — has a straightforward answer: for most UK structural projects, professionally installed liquid waterproofing costs £40–£120 per m² including labour and materials, depending on the system, the amount of detailing and the condition of the substrate. These are installed prices from a specialist contractor, not material-only figures, and they cover the full build-up — primer, membrane, detailing reinforcement and, on trafficked decks, the wear course.

To put that in project terms: a typical 40m² residential balcony run refurbished in polyurethane lands around £2,500–£4,000; a 300m² podium deck in a buried build-up typically falls between £15,000 and £30,000; and a 1,500m² car park deck in a trafficked PMMA system, phased to stay open, sits in the £120,000–£200,000 range depending on repairs and detailing. Every one of those figures starts with a survey, because the deck you can see is rarely the whole story.

System	Cost per m² (UK)	Cost per m² (London)
Cold-applied liquid membrane	£40 – £70	£50 – £85
Polyurethane system	£50 – £90	£60 – £110
PMMA fast-cure system	£70 – £120	£85 – £145
Surface preparation (where required)	£10 – £30	£12 – £35

Detailing is the real cost driver: a plain 500m² deck is quick work, while the same deck crossed by upstands, outlets, movement joints and penetrations carries far more hand detailing per square metre. Small areas also cost more per m² because mobilisation, preparation and detailing are fixed regardless of size — a single 15m² balcony will always cost more per square metre than a 2,000m² podium.

Other factors that move the price: the condition of the existing deck (concrete repairs and re-profiling come before waterproofing, not instead of it), whether an existing failed membrane has to be stripped and disposed of, access and working-at-height requirements, out-of-hours or phased working on live sites, and the guarantee period specified — longer manufacturer-backed guarantees generally require higher-build systems and more inspection. A written specification and fixed quotation after survey protects you from all of this arriving as a variation later.

Be wary of quotes far below these ranges. The material cost of a genuine full-build system sets a floor under honest pricing; quotes dramatically under it usually mean a thin single coat, skipped preparation or no detailing reinforcement — the three shortcuts behind almost every failed liquid membrane we are asked to replace.

Prices are indicative, exclude VAT, and assume reasonable access and a sound substrate. See our full waterproofing cost guide for detailed pricing by structure type.

Liquid vs Sheet Membranes

Both approaches work when specified and installed correctly — the right answer depends on the structure:

• Details and penetrations — liquid wins decisively. Every outlet, post, upstand and pipe is wrapped in a continuous membrane rather than cut, lapped and welded. On detail-heavy decks this removes the majority of potential failure points.
• Seamless and fully bonded — no welds or laps to fail, and no lateral water tracking beneath the membrane, so any future defect is easy to locate and patch.
• Complex geometry and refurbishment — liquid is faster on stairs, ramps, plinths and irregular decks, and can often overcoat a prepared existing surface without full strip-off.
• Very large, simple areas — sheet membranes win on big, flat, uninterrupted slabs with few penetrations, where factory-controlled thickness and rapid rollout give the economic edge.

Programme matters too. Liquid systems need suitable weather windows and cure time between coats (unless PMMA is specified), while sheet systems are less weather-dependent once welding conditions are met. On refurbishment, liquid usually wins again: it tolerates the stepped, patched, irregular substrates that real 30-year-old decks present, where dressing a sheet membrane over the same surface would mean hundreds of vulnerable cuts and welds.

Most of our structural work — decks, podiums, balconies, basements — sits firmly in liquid territory. Where a hybrid design serves the structure better, we will say so at survey stage; we install both, so the recommendation follows the structure rather than the product we happen to sell.

Nationwide Coverage

We install liquid applied waterproofing across the UK from regional teams. Recent demand has been strongest for liquid waterproofing in Birmingham and the Midlands, alongside regular deck and podium projects in Bristol, Exeter and the South West, Southampton and the South Coast, and London and the Thames Valley, including Bracknell and Reading.

Wherever your structure is, the process is the same: a free site survey, a system specification matched to the exposure and the programme, and a fixed itemised quotation — the same approved installers, the same manufacturer-backed guarantees, whether the deck is in central London or a coastal car park in Devon. See our membrane installation service covering 50 cities for your nearest team.

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