Rendering in Bradford

Stone that stays bare, and walls that carry render

Bradford Council’s homeowner guide on stone elevations says the local carboniferous sandstone of Bradford and Airedale, and the gritstone of Wharfedale, are the predominant building materials in the district’s conservation areas. Its advice is not to paint or render stonework: the stone buildings are traditionally bare, and paint and render can damage the stone by trapping water. A weathered stone wall is usually a job for repointing in a soft mortar and replacing the worst stones, not for render.

The council’s render guide identifies where render is traditional: late 19th and early 20th century Old English and Arts and Crafts houses, usually on the upper storey over stone, limewashed white or finished as pebbledash or roughcast. Beyond those, render belongs on brick and blockwork houses, extensions, exposed party gables and the brick and block walls of commercial and industrial buildings.

Choosing between repair, recolouring, renewal and removal

Tap the render first; the council’s guide says a hollow sound may mean it is loose. If the render is sound and you want a fresh or different colour, a respray with a coating that suits the render is the lighter job, keeping paint off the stone sills and heads. If the damage is confined to patches, such as a hollow band under the eaves, cracks round a bay or a blown strip at the base, a render repair cuts out the loose areas and patches them in a compatible material.

If the hollow areas join up across a wall, or hard cement render on a stone wall is cracking and trapping water, the render is renewed, in lime for an older stone building. If a stone house was dashed or rendered later, removing the covering and repointing the stone is often the better outcome, while original dash on an Arts and Crafts house is repaired rather than stripped. External wall insulation suits some solid brick and already-rendered walls, but not traditionally bare stone.

How the work is carried out

Each job begins with an inspection: tapping for hollow render, following cracks to their cause, and checking the damp-proof course, sills, copings, gutters and gullies, because water from those points causes much render failure. Failed render comes off by hand where the stone behind is soft. The wall is repaired and repointed, dense backgrounds are primed or given a stipple coat, and lime backgrounds are dampened. New render is built up in coats, with mesh at window corners in modern systems. The edges are formed on beads, with a bell-cast profile at the foot of the wall above the DPC, angles on the corners and stops wherever render meets stone. The work is protected while it cures, finished and then kept clean and in repair.

Commercial, industrial and new-build work

On industrial units, shops, flats and new estates, the background is usually block, brick, concrete or board, often sprayed in one thick through-coloured coat and scraped to texture, or finished with a silicone thin coat over a meshed base. Large walls are divided into bays so the finish comes out even, and occupied buildings are worked around their entrances and deliveries. The district’s historic warehouses are another matter: the council’s Little Germany assessment describes them as honey-coloured local sandstone, and most are listed, so they are repaired in stone.

Bradford has 60 conservation areas. In any of them, rendering a house needs planning permission rather than relying on permitted development rights, so speak to the council first.