Roofing detailedto keep water outfor decades

Pitched roof work covers cut roofs formed on site, trussed roofs, and re-roofing of existing slopes. Coverings include concrete and clay plain tiles, interlocking tiles, and natural or fibre cement slate, laid to the correct pitch, headlap and batten gauge over a breather membrane. Ridge, hip and verge details can be dry-fixed or bedded, and dry systems are usually more durable on exposed elevations.

Where a new extension roof ties into an existing slope, the tie-in is the critical detail: valleys formed properly, tiles cut and matched, and the existing covering opened up only as far as needed. On re-roofing work, battens, membrane and any defective timber are dealt with rather than covered over.

Flat roof specification depends on span, achievable falls, insulation requirement, whether the roof is walked on and whether it is seen from windows above. Options include single-ply membrane, EPDM rubber, high-performance felt systems and GRP, each with different detailing at upstands, outlets and trims. Falls are created with firrings and taken to outlets that are sized and positioned to clear the water, with upstands taken high enough at abutments.

Dormer construction combines all of it: timber cheeks, insulation, breather membrane, a flat or pitched roof over, cladding or tiling to the cheeks, and lead or proprietary flashings where the dormer meets the main roof. Leadwork covers cover flashings, step flashings into brickwork joints, soakers, valleys, chimney aprons and back gutters, dressed in the correct code of lead and fixed to allow movement.

Roofs can be insulated at ceiling level, at rafter level as a warm roof, or as a cold roof with a ventilated void: and the choice dictates where the vapour control layer and the ventilation path go. Loft conversions normally need insulation at rafter level while maintaining ventilation, and flat roofs are usually built as warm roofs with insulation above the deck. Rooflights and Velux windows are installed with the manufacturer's flashing kits for the specific covering.

Fascias, soffits and rainwater goods complete the roof: gutters sized and laid to fall, outlets and downpipes discharging to a drain or soakaway rather than onto brickwork, and eaves ventilation kept clear. Roofing is delivered as part of our extension, loft and new build contracts across Sidcup, Bexley, Dartford, Bromley and the surrounding areas.

Roofing cost is driven by area and pitch, the covering specified, access and scaffolding, and how much of the structure, leadwork or rainwater goods needs attention once the covering comes off. Scaffolding is a safety requirement on most roof work and is priced in from the start. Where a roof is being stripped, we allow for replacing defective battens and membrane rather than covering them over, and we tell you what we find.

Weather governs the programme. Stripping a roof is planned in sections that can be made watertight the same day, with temporary protection available, and membrane and covering work is not started into forecast heavy rain. That is a programming decision, and it is one of the practical advantages of the roof being delivered by the team running the whole build.

Maintenance is worth understanding once the work is done. Gutters and outlets need clearing so water leaves the building instead of backing up over fascias, moss build-up on north-facing slopes holds moisture, and flat roof outlets are the single most common cause of a later leak. Correctly detailed leadwork, properly lapped coverings and roofs laid to positive falls are what keep the maintenance to that short list rather than to repeated repairs.