Plain-English definitions of the roofing terms you are most likely to hear from a Cambridge roofer — so you can understand quotes and make confident decisions.
Call Now: 0122 366 6465This glossary explains common roofing terms in plain English for Cambridge homeowners. From nail sickness on 1960s estates to lime mortar on Victorian chimneys, understanding these terms helps you read quotes clearly and spot good advice. For help with any of them, call 0122 366 6465.
Nail sickness is the gradual corrosion of the iron or steel nails that fix roof tiles and slates in place. As the nails rust and weaken, tiles begin to slip even in moderate winds. It is especially common on Cambridge's 1960s and 70s concrete-tile estates, where the original galvanised nails are now reaching the end of their life.
Lime mortar is a traditional mortar made from lime rather than modern cement. It is softer and more breathable, allowing period brickwork to flex and release moisture. On Cambridge's Victorian terraces and pre-1920 chimneys, lime mortar is essential — hard cement mortar traps damp and cracks the soft historic brick over time.
Flashing is the weatherproofing material, usually lead, fitted where a roof meets a wall, chimney or valley. It seals the join against rain. Well-dressed lead flashing lasts fifty years or more; failed or lifted flashing is one of the most common causes of leaks on Cambridge roofs, particularly around chimneys.
EPDM is a synthetic rubber membrane used for flat roofs. Supplied in large single sheets, it has very few joints, resists moisture well and tolerates temperature change. For Cambridge garages and extensions — especially in damper riverside areas like Chesterton — EPDM is often the most reliable and cost-effective flat-roof choice, lasting twenty-five years or more.
GRP, or glass-reinforced polyester, is a fibreglass system used for flat roofs. Applied as a resin and matting laminate, it cures into a hard, seamless, walkable surface. GRP suits Cambridge extensions and balconies, but must be installed in dry conditions above five degrees, so local installations are scheduled around the weather.
A dry fix or dry ridge system mechanically fixes ridge and hip tiles with screws and clips instead of bedding them in mortar. It needs no maintenance and resists wind far better than mortar. On exposed Cambridge and fenland roofs, dry ridge systems prevent the ridge-tile failures that cause many storm callouts.
A breathable membrane is a vapour-permeable underlay fitted beneath roof tiles. It keeps wind-driven rain out while letting moisture escape from the roof space, preventing condensation. Fitted on every modern Cambridge re-roof, it replaces old non-breathable felt and is particularly valuable in Cambridge's damper areas where trapped moisture would otherwise rot the roof timbers.
The fascia is the board running along the roof edge that carries the guttering; the soffit is the underside board that closes the gap between the wall and roof edge. Together they protect the rafter ends and ventilate the loft. On Cambridge's post-war estates, rotten timber fascias are a very common replacement job.
Still unsure about a term on your roofing quote? We are happy to explain.
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