On Shenfield's inter-war houses, the flat sections that usually need re-roofing are the small ones: bay window tops, porch canopies and dormer cheeks. These were rarely built to last as long as the main pitched roof, and many are now on their second or third covering. Re-roofing them well is mainly a question of choosing a suitable flat-roof system and detailing it to sit neatly against tiles, render and brickwork that may be ninety or more years old.
Inter-war houses and their flat additions
Most of Shenfield's 1920s and 1930s homes are semi-detached or detached houses with steep, tiled main roofs. The flat areas are secondary: they cap projecting bays, shelter front doors, or form the small roofs over dormer windows added during the same period or later.
The original coverings were typically built-up felt or, on some properties, lead or zinc. Felt degrades with sunlight and movement, so the failures seen today are often a single weak section rather than a whole roof. A surveyor will usually inspect the deck (the timber boarding beneath the covering) as well as the surface, since long-standing leaks tend to rot the boards and joists underneath.
Bay window and porch roofs
On Shenfield's inter-war houses, the flat sections that usually need re-roofing are the small ones: bay window tops, porch canopies and dormer cheeks.
Bay roofs are small but exposed, and they take water shed from the wall and window above. The covering wraps over a shallow timber structure and meets the main wall at an upstand (the turned-up edge where the flat roof meets a vertical surface). Failures here often start at that junction or at the front edge, where the trim and drip detail throw water clear of the brickwork.
Porch roofs raise similar issues on a smaller scale. Many Shenfield porches are open or part-enclosed, so the flat top is visible from the street and any patch repair shows. Common options for re-covering these areas include:
- Reinforced bitumen membranes — the modern equivalent of traditional felt, applied in layers.
- Single-ply membranes — sheet materials welded at the seams.
- Liquid systems — applied wet and cured to form a seamless coat, useful around awkward shapes.
- Lead or other metals — closer to the original on some houses, though heavier and more costly.
The right choice depends on the size of the area, how it meets the surrounding fabric, and how visible it is.
Dormers and loft conversions
Flat-roofed dormers are common where inter-war lofts have been converted. The dormer cheeks (the side walls) and the small flat top form a box that interrupts the pitched roof, and the junctions between the two are where water finds its way in. Lead flashings and soakers tie the dormer into the surrounding tiles.
When re-roofing a dormer, the flat top and the flashings are usually addressed together, because a new covering laid against tired old flashing rarely lasts. Where a loft conversion is planned rather than already in place, building control approval and, in some cases, planning permission will apply — particularly if the dormer faces a road or alters the roofline noticeably. Anyone considering this should check with Brentwood Borough Council before work begins.
Matching new work to older fabric
The visual challenge on these houses is making new flat roofing sit comfortably against original materials. Inter-war brick, render and clay tiles weather to colours that fresh components do not match straight away. A careful job pays attention to the things that show: the colour and profile of trims, the line of the front drip, and the way new lead is dressed against old tiles.
Where an upstand meets render, the detailing should allow the render to be made good without trapping moisture behind it. On a terrace or a pair of semis, keeping the bay and porch roofs consistent with the neighbouring property helps the work read as part of the original house rather than a later addition. Reclaimed or colour-matched flashings are sometimes used for the same reason.
Last reviewed: June 2026