Roofers in Petworth

Petworth is a hill town on a sandstone ridge at the southern edge of the Low Weald, about four miles north of the chalk scarp of the South Downs. The conservation area appraisal says steep clay plain-tile roofs predominate there, varied by gables, hips and half-hips. That one sentence tells a roofer a good deal. A plain tile is small and thin, laid in overlapping courses, and on a steep slope the roof sheds rain quickly but every tile has to stay put against the pull of gravity and the push of the wind. Hand-made tiles have a slight camber and a mottled colour that machine-made ones rarely copy exactly, so when a few need replacing we look for a close match, often from reclaimed stock. A hip is the angled rib at an outer corner, where two slopes of tile come together. A half-hip is a gable whose top is clipped back into a small hipped end, so a house with one has a short sloping triangle at the top of the gable wall where a flat wall might have been. Each one adds a line of cut tiles, and each cut is a place to look for slipped or cracked tiles. Plain tiles are also laid with a wide overlap, so a tile that cracks usually has a sound one beneath it, and a single replacement can restore the roof without any further stripping. That is the kind of small, accurate repair we prefer to recommend before a new roof comes into the conversation.

1.1 Looking after clay plain tiles

Clay is a durable covering. Marley cites a Building Research Establishment minimum of 60 years for clay, while a building conservation article calls that number unreliable for old peg-tile roofs. On old roofs the tiles often outlast the timber and nails beneath them. Marley's clay plain tiles are rated to minimum pitches of 30 to 40 degrees, depending on the model, which is the territory Petworth's steep roofs sit in. When we survey, we check for tiles that have slipped, spalled on the face or cracked across, and for soft or rotten battens, the timber strips each tile hooks onto. A roof that has lost its nibs, the little lugs on the back of a tile, is slipping slowly even if nothing has fallen yet.

1.2 Ridge and hip tiles on a steep slope

The ridge capping runs along the top. BS 5534 was revised in 2014, and since then nobody leans on a mortar bed alone for the ridge and hip tiles. That is the job of screws, clamps or a dry-fix system, which BS 8612:2018 tests for ridge, hip and verge. An older Petworth roof may still have mortar beds that have crumbled where the weather reaches them first. Replacing the bed and adding fixings is a modest repair. Our ridge tile repairs page explains the process, and our plain clay tile roofs guide covers the covering itself.

Petworth's walls carry as much character as its roofs. The appraisal names local sandstone and greensand as the materials, and the Sacred Heart church shows how they were used, with flint chequer panels set into the greensand. A tiled roof that runs into a stone wall needs a joint that moves a little and still keeps water out. Mortar fillets alone crack as the materials flex at different rates, which is why traditional work uses lead set into a groove in the wall, known as a chase, with the other edge dressed over the tiles. Lead comes in codes by weight, and Royston's cast-lead brochure lists codes 4, 5 and 6 as suitable for flashings. Choosing the code is part of a good flashing job, and on a steep roof the lead is also dressed with enough overlap that driving rain cannot track behind it.

3.1 Chimneys, valleys and half-hip junctions

A chimney stack on a steep roof needs a flashing round its base, a tray or gutter behind it and a lead apron on the downhill side. A valley is the trough between two slopes at an inner corner, collecting water from both, so it needs a properly lined channel. Half-hips and hips create further junctions, so a Petworth roof often has more joints than a plain gable. A damp patch on a ceiling below a stack usually points to a failed joint at the stack, and not necessarily a leaking tile, so we trace the water before proposing a fix, which often means a short look in the loft after rain, and sometimes a hose test, working from the bottom of the roof upwards. Our chimney repairs page covers repointing a stack, renewing its flashings and checking the flaunching that beds the pots.

3.2 Working safely above a steep slope

A steep roof is not a place to improvise. West Sussex County Council licenses scaffolding that obstructs the highway. The firm erecting it files the application, at least 10 working days ahead, and a month's licence is listed at £266. We plan access first and build the programme around it, because the ladder positions, the scaffold lifts and the delivery of tiles all depend on where the roof can safely be reached. Bats and nesting birds are covered by wildlife law, so the roof void gets a look before any stripping starts. When the survey is finished, the whole job is priced as one written total.