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Clarke Roofing rebuilt two failing flat roofs on an occupied residential block in The Drive, Hove. Both were stripped to the joists and rebuilt with an 18mm plywood deck, tapered insulation and a Sika warm roof felt system, with lead flashing to the abutment and GRP encapsulation over the parapet coping stones. Residents kept their gas and TV throughout.
The Drive is a mid-20th-century residential block in Hove, with flats, communal gardens and resident parking. Two separate flat roof areas cover the upper floors, and both had reached the point of needing replacement rather than repair.
Drainage across the existing roofs was poor, the insulation was outdated, and there were details where water could get into the building below. We stripped both roofs back to the joists and rebuilt them.
Both roofs got the same build-up: an 18mm plywood deck, tapered insulation and a Sika warm roof felt system. The differences were in the preparation and the perimeter details.
Area one abuts a wall, so that joint needed Code 4 lead flashing, and the roof drains through gutters and downpipes into the existing drainage. Area two is surrounded by parapet walls with coping stones, one of the places water had been getting into the building, and it needed new chute outlets to clear water off the roof. It also had a live gas pipe running across it, which had to be moved before stripping could start.
We treated them as two separate jobs.
We put up scaffolding for safe access and moved the TV aerials clear before stripping began. The existing covering and decking came off back to the joists, which let us inspect the structure before anything new went down.
The rebuild started with a new 18mm plywood deck, followed by tapered insulation and a Sika warm roof felt system. The tapered boards do two jobs at once. They bring the thermal performance of the roof up to current standards, and they form the falls that move rainwater towards the outlets.
We replaced the rooflight and dressed Code 4 lead flashing into the wall where the roof abuts it. New fascias, soffits, gutters and downpipes finished the perimeter, connected into the existing drainage.
This roof needed more preparation before we could strip anything. A live gas pipe crossed the working area, so we brought in a specialist to temporarily disconnect and reroute the supply before any stripping began, and the aerials came off at the same time.
With the roof clear, the old covering and deck were removed and rebuilt using the same 18mm plywood, tapered insulation and Sika warm roof system as area one.
Water had also been getting in around the parapet coping stones. We encapsulated the parapets in plywood and GRP trims, which deals with one of the more troublesome details on the roof. New chute outlets, fascias and rainwater goods went on to carry water away from the building.
Once the roof was watertight, the gas service and aerials were reinstated and tested.
The build-up starts with an 18mm structural plywood deck, which gives the new roofing system a solid base to sit on. Above that go the tapered insulation boards, which raise the thermal performance of the roof and create the falls towards the drainage outlets. The waterproofing over the top is a Sika warm roof felt system, a multi-layer bituminous membrane.
The vulnerable details are dealt with separately. Code 4 lead flashings protect the abutment, GRP trims cap the parapets, and new fascias, soffits, gutters, downpipes and chute outlets carry rainwater away from the roof and the brickwork.
The old roof build-up has been replaced with a warm roof system and tapered insulation. As well as improving the thermal performance of the roof, keeping the insulation above the structural deck reduces the risk of condensation forming inside the roof build-up.
Standing water is what finishes most flat roofs early. The tapered insulation created falls towards the outlets, so rainwater now clears the roof instead of collecting in low areas, and the new gutters, downpipes and chute outlets take it away from the building.
The coping stones on the second roof had been one of the routes water was taking into the building. Encapsulating the parapets in plywood and GRP trims puts a proper waterproof detail over them, and the Code 4 lead flashing does the same job at the abutment on the first roof.
The block stayed occupied throughout, so access and existing services had to be planned around the people living there. Moving the gas pipe and aerials, then reinstating both once the roof was finished, meant residents kept their gas supply and TV reception while the work went on.
Both roofs were stripped back rather than patched over, so the flats below now sit under new decking, insulation, waterproofing, rooflights, perimeter details and rainwater goods.
Flat roofing is one part of the business. On flat roofs we install built-up bituminous, liquid waterproofing and single-ply membrane systems, and we are accredited installers for the leading UK and European manufacturers, Sika among them.
The wider service list covers slating and tiling, lead, copper and zinc work, rooflights, green roofs, metal lightweight roofing and timber shingles, along with the trades that tend to come with a roof job: carpentry, brickwork, stonework and decoration. If you need to know the condition of a roof before deciding anything, we also run aerial surveys.
The work splits across domestic, commercial and restoration and heritage projects across East Sussex, West Sussex, Kent, Surrey, Hampshire and London. Everything is carried out to current regulations and to National Federation of Roofing Contractors recommendations, new projects and re-roofs carry a minimum 10 year guarantee, and we do not ask for deposits in advance.
If a flat roof is holding water, leaking around the parapets, or reaching the point where repeated repairs no longer make sense, Clarke Roofing can inspect it and advise on what the work involves.
Get in touch to arrange a survey, or have a look at other projects we have completed.