Flat roofing in Bognor Regis

The covering matters less than the roof underneath it, but each material suits a different shape of roof, and each has its own weak spot.

Most flat roofs in Bognor Regis and across West Sussex are covered in one of three materials. The choice shapes how the roof looks, how it is detailed at the edges and how long it can be expected to last. Whichever you pick, the quality of the finished roof depends far more on the preparation underneath than on the name printed on the roll. We still start with the material, because it is usually the first question people put to us.

1.1 Torch-on felt

Torch-on felt is a built-up bitumen membrane. Two or three layers are fused to the deck, the flat boarded base of the roof, by warming the underside with a gas torch, and the laps are sealed as each roll goes down. Less, the home improvement cost guide last updated in March 2026, puts its life at 10 to 20 years and notes that a good felt job can last 20 years while a poor one might fail in under ten. That gap between good and poor is workmanship: how well the laps are sealed, how neatly the upstands are finished and whether a cap sheet is fused over the base layers. Felt suits larger, plain roofs such as garages and wide extensions, where the area is simple and the edges run straight.

1.2 EPDM rubber

EPDM is a synthetic rubber membrane, usually supplied as one sheet cut to the size of the roof and glued down to the deck. With so few joints there are fewer places for water to find a way in. GreenSpec gives single-ply membranes an expected service life of 20 to 30 years, while Less quotes 30 to 50 years for EPDM, and the difference between those two sources is a good reason to treat any lifespan as a range rather than a promise. Rubber suits small roofs with simple outlines. Corners, rooflight kerbs and awkward junctions are dressed with preformed pieces and adhesive tape, so the neatness of those details tells you most about the person laying it.

1.3 GRP fibreglass

GRP, glass-reinforced plastic, is a resin and glass-fibre laminate built up in place on the deck and finished with a topcoat. It forms a hard, joint-free skin that follows irregular shapes, which is why it is often chosen for roofs with several pipes, curved edges or an awkward outline. Less puts its life at 25 to 40 years. Because the laminate is rigid, the deck below it must be stiff and well fixed: a deck that moves will crack a GRP roof along the line of the movement. Our guide to choosing between EPDM, GRP and felt sets the three side by side.

Liquid-applied coatings are the fourth option. They are rolled or brushed over an existing covering that is still sound and dry, and they can extend the life of a roof that has only surface wear. They cannot cure a soft deck, a ponding roof or a failed upstand, so we look underneath before recommending one. Sheet metals such as lead are used on small roofs and dormers; Less gives a lead flat roof 50 to 100 years, which suits detail-led jobs better than a wide garage roof.

Not every tired flat roof needs stripping. The survey decides, and we say which of three routes fits before we talk about money.

The verdict we give is one of three: maintain the roof, re-cover it or rebuild it. A reliable verdict needs evidence, which is why we photograph the covering, the outlets, the edges and the ceiling below, then explain what each picture shows. You can keep the photographs and show them to anyone you like.

3.1 What the survey looks at

We start with the water. Staining on the ceiling, a musty smell or bubbling paint tells us where it has been getting in. On the roof we look for splits, blisters, open laps, lifted upstands, which are the short upturns of membrane where the roof meets a wall, and outlets clogged with leaves or grit. We press along the deck for soft patches. A roof that is dry and firm underfoot has choices; one that is spongy or stained underneath is usually past patching. We also ask when the roof was last done and with what, because an old felt roof and a young rubber one fail in different ways.

3.2 When a repair is the right call

If the covering is otherwise sound, one split, a failed upstand or a blocked outlet can be put right for a small sum. Less puts small flat roof repairs at £150 to £500, a very different outlay from a new roof, and we put forward the smallest job that cures the fault for good. A reliable flat roof repair needs sound material around it to tie into, and the survey shows whether that exists. Where the deck has stayed dry, a repaired upstand or a resealed outlet can carry on for many more seasons. Our roof repairs service covers leak tracing across every kind of roof.

3.3 When a new roof costs less in the end

Patches pile up. A roof with several repairs already, ponding across its middle, felt that has turned brittle or insulation that is saturated is telling you the covering has reached the end of its useful life. Felt is quoted at 10 to 20 years, so an older roof showing wear is often better replaced than nursed. Replacement also lets the fall be corrected, the insulation upgraded and the edges rebuilt, none of which a patch can do.

The survey also settles whether a new covering can go over the old. Laying over a wet or failed layer traps moisture, so the old layers usually come off, and the weight and fire performance of any new covering need checking against the structure. That is why we ask for photographs and a deck test before we offer a verdict, and why a quick figure from a doorstep caller tells you very little.

Flat roofs fail at their edges and junctions long before the middle of the membrane gives way, and sea weather tests every one.

Flat roofs turn up wherever a pitched roof cannot reach: over a rear extension, a garage, a porch, the top of a dormer, a shop front or a small block of flats. We work on all of them, from Aldwick and Felpham through Chichester and the harbour villages to Littlehampton, Worthing and the Downs towns. Each has its own habits, but the weak points are nearly always the same: where the flat roof meets a wall, where it ends at an edge and where something pokes up through it.

5.1 Extensions and dormers

Where a flat extension roof meets the house wall, the membrane turns up the brickwork as an upstand and is covered by a lead flashing, a strip of lead let into the wall and dressed over the top edge. Water that gets behind a poorly sealed flashing runs down the inside face of the wall, so the stain appears indoors beneath the roof rather than at the junction. A flat dormer roof adds cheeks, the vertical side walls of the dormer, with their own lead and tile junctions. These are small areas that carry a lot of risk, and they are the first details we photograph on a survey. Our guide to extension and dormer flat roofs goes through them one by one.

5.2 Edges, outlets and rooflights

The edge trim is the metal or plastic profile that finishes the membrane at the perimeter and throws water clear of the fascia, the board that carries the gutter. A trim set too low sends water behind the gutter; one that is not sealed lets wind lift the edge of the covering. Outlets and gutters need clear paths and a fall towards them. Rooflights sit on upstands, and Approved Document L lists 2.2 W/(m²·K) as the limiting U-value for a rooflight, the measure of heat lost through it, with 0.35 as the maximum for an upstand built on site.

5.3 Commercial and shared roofs

A commercial flat roof raises questions that a garage does not: who else uses the roof, how it is reached, whether the building stays occupied during the work and how rainwater is carried away. Shops, workshops and flat-roofed blocks near the seafront tend to have bigger areas, with rooflights and plant to work around, and the outlets are sized to match. Our commercial roofing service covers those buildings in detail.

Near the sea, gales and driving rain test every edge, which is a reason to look at these details regularly rather than only when something leaks. Maintenance is simple: clear the outlets and gutters after leaf fall, glance at the laps and edges, and photograph anything that changes. A short note to us with those photographs is often all it takes to tell whether a small repair now can save a larger job later.