Roof waterproofing that starts where the water actually gets in.
Flat slabs, sloping tiled roofs and sheet roofs surveyed, the entry point traced, cracks and junctions repaired, then a membrane taken up the parapet and around every outlet, so the ceiling below stays dry.
- Free site inspection
- Written, itemised quote
- 1-year workmanship warranty
- Same-day callback
At a glance
What does roof waterproofing actually involve?
Sealing the whole top surface of the building against rain, not just brushing a coating over it. We survey the roof and the ceiling below, trace where water is getting in, repair cracks, joints, outlets and penetrations, correct falls where water is standing, then apply the agreed system and water-test it.
When this is the answer, and when it is not.
Sending you to the wrong service wastes your money and our time. This is how to tell.
This is likely right if
- Damp patches, stains or drips appear on the top-floor ceiling after rain
- The previous roof treatment has blistered, cracked or lifted away at the parapet upstand
- Water stands on the roof for hours after a shower instead of reaching an outlet
- You are about to repaint the top floor and want the source dealt with before the finish goes on
Something else comes first if
- Concrete is spalling and reinforcement is exposed or rusting, that needs a structural engineer's assessment and concrete repair before any membrane is laid over it
- The water is coming from an overflowing tank, a leaking supply line or a blocked drainage stack, which is a plumbing repair rather than a roof one
- It is a common or shared terrace above your flat, the association has to give permission and agree the scope before anyone can start on it
What the service includes.
Roof and ceiling survey
We walk the roof and examine the ceiling below, ideally while it is still wet, recording cracks, failed old coats, ponding marks, blocked outlets and the condition of every junction and penetration.
Stripping and cleaning
Loose coating, lifted felt, moss, algae and surface laitance taken off. A new layer bonds to whatever is under it, and a layer that has already let go of the slab will take the new one with it.
Crack, joint and penetration repair
Cracks cut open to a V and filled, the parapet-to-slab junction and cold joints coved with a fillet, and vent pipes, outlet mouths and mount bolts sealed with mesh reinforcement.
Falls and rainwater paths
Where water stands, screed is built back to a fall towards the outlet, and outlets and gutter lines are cleared or reformed so the roof drains instead of holding.
Membrane or coating system
Applied to the agreed system and coat count, taken up the parapet to a stated height and turned over the drip edge, so water can't track in behind the termination.
Water test and handover record
The roof flooded or hosed and checked from below, with photographs of the stages that get covered up, handed over along with a written warranty and its stated conditions.
Not included, or quoted separately
- Structural repair, spalling concrete, exposed reinforcement, or a slab crack that needs an engineer's opinion
- Plumbing work: an overflowing tank, a leaking overflow line or a blocked drainage stack, even when the stain below looks exactly like a roof leak
- Replacing the roof structure, or a full re-lay of tiles, sheets, purlins or battens beyond the repair points we've quoted
- Shifting solar panels, water tanks, dish antennas or AC outdoor units, and any electrical disconnection those need
- Ongoing cleaning of gutters, valleys and rainwater outlets after handover
The sequence.
Survey, preferably in the wet
We come while the leak is live if we can. A dry roof hides ponding lines and the exact point water is getting in, and a dry ceiling hides how far the water has travelled.
Trace the source before quoting
Ponding or hose tests on the suspect sections, tank and plumbing lines isolated, and the ceiling below examined. We aren't willing to coat a roof and hope the stain stops.
Agree the system and the falls
Roof type, exposure and what's already on the surface decide the system. Your quotation states the products, coat count, upstand height, and whether screed to fall is included.
Strip, clean and let it dry
Failed layers removed, the surface ground and washed, then left to dry through its depth. Coating over trapped moisture is the commonest reason a new roof treatment blisters within a season.
Detail the weak points first
Junctions, coving, outlets, penetrations and cracks reinforced and treated before the field coats go on. Roofs leak at details, not in the middle of an open slab.
Coat, cure and test with you
Coats applied and given their curing time, then a water test with you present, the roof left clear of our debris and the handover record issued.
What moves the price on this job.
We do not publish a rate, because it would change once someone measured your property. These are the variables that decide it.
- Roof type, flat RCC, sloping slab, Mangalore-tiled or sheet roof, each needing a different system and different labour
- Measured roof area, plus the running metre of parapet upstand, junctions and gutter line, which is far slower work than the open field
- How much old coating, felt or screed has to be stripped before anything new can be laid
- Whether falls have to be rebuilt in screed, or the existing slope can be used as it is
- The number and awkwardness of penetrations, outlets, vent pipes, tank bases, solar frames and AC mounts
- Access and working at height: staircase roof, ladder-only reach, or a gutter line hanging over a neighbour's boundary
Roof Waterproofing — your questions.
Why is the damp patch nowhere near where the water gets in?
Water entering a roof rarely drops straight down. It runs across the top of the slab until it finds a shrinkage crack, a cold joint or a conduit, then travels along the underside of the slab or a beam before it finally drips. On a tiled roof it runs down a batten or rafter first. That's why we trace and test the entry point instead of coating the ceiling under the stain.
Can you waterproof the ceiling from inside instead?
No, and it is worth knowing why. Water arriving from above presses against the back of anything applied from below, and that pressure lifts it off, you get a fresh blister rather than a dry room. Interior treatment has its place only after the roof itself is sealed, to make the damaged plaster and finish good again. On its own it hides the leak while the slab keeps getting wet.
The roof is leaking now, in the middle of the rain, can you seal it straight away?
Survey, leak tracing and urgent crack sealing can be. Full systems mostly can't. Membranes and cementitious coatings need a substrate that's dry through its depth and then a settled spell to cure. Moisture trapped underneath turns to vapour in the next day's sun and pushes the coating off as blisters. We often diagnose during rain, when the leak is showing, and apply once there's a dry window.
Does the old bitumen felt or coating have to come off?
Wherever it is loose, blistered or lifting at the edges, yes. A new membrane bonds to whatever is beneath it, if that layer has already let go of the slab, the new one fails with it and you pay twice. Sound, well-bonded sections can sometimes be cleaned, keyed and overcoated, but only after we've checked adhesion and confirmed the old and new systems are compatible.
Ours is a Mangalore-tiled roof, not a concrete slab, is it the same work?
No. On a tiled or sheet roof, water almost always enters at a detail rather than through the surface: cracked or slipped tiles, failed ridge and valley mortar, short or wind-facing sheet overlaps, and fastener washers that have perished so the bolt hole is now the leak. The work is repair, re-bedding and lap sealing, with coating used only where the material suits it. We survey the underside as well as the top.
Let us look at your walls first.
Tell us about the property and we will set up a free colour and wall inspection. You get a written, itemised quotation afterwards, with no obligation to go ahead.
- We call you back the same day to get a picture of the property and the surfaces.
- We agree a time and come out for the free inspection.
- You get the written scope and itemised quotation.
- Nothing starts until you approve it.