Roughcast and pebble dash repairs in Paisley

Not every cracked wall needs a full re-roughcast. Tell us what you're seeing and we'll pass it to one trusted local firm, who'll tell you honestly whether a repair will do or the wall needs redoing. Free, and no obligation.

This page is about fixing what's there: patching roughcast, repairing pebble dash and sorting cracks before they get worse. If the whole coat has had it, our page on roughcasting and harling in Paisley covers a full redo.

What goes wrong with roughcast

Roughcast fails in a fairly predictable order. First, a few fine cracks. Water gets into them, and in a cold snap it freezes and pushes the cracks wider. Over a few winters the coat starts to lose its grip on the wall behind. At that point it can still look fine from the street, but it sounds hollow when you tap it. Then pieces start to fall off.

The earlier you catch it, the more likely a repair will do. A crack is cheap to deal with. A section that's come away from the wall is a bigger job. Once hollow areas are spread across most of a wall, patching is throwing good money after bad.

How to check your walls

• Look for cracks, especially round the corners of windows and doors, along the line of the floors, and at the corners of the house. Those are where the wall moves and the coat is under most strain.
• Tap it. Use your knuckles or the handle of a screwdriver. A dull thud is good. A hollow, papery sound means the coat has come away from the wall behind.
• Look underneath. Bits of roughcast on the path, or stones from pebble dash in the flower bed, mean something above is coming loose.
• Check inside. A damp patch on an inside wall that's worse after windy, wet weather can be water getting in through a crack outside.

Patching, or a full re-coat?

A repair usually makes sense when:

• The damage is in one or two places, such as round a single window or one corner.
• The rest of the wall sounds solid when you tap it.
• There's an obvious cause that's now fixed, like a leaking downpipe or an old satellite dish bracket.

A full re-coat of that wall is usually better value when:

• Hollow patches are scattered all over, not just in one spot.
• There's already a patchwork of old repairs in different colours and textures.
• The coat is falling off in more than one place.
• Damp is getting into the house through several cracks.

Re-coating doesn't have to mean the whole house. Often it's one gable end or the wall that faces the weather. Our roughcasting cost guide explains how prices for a full wall compare with smaller jobs.

How a repair is done

The loose material round the damaged area is cut back to sound roughcast, so the repair isn't sitting on something that's about to fall off. Any damage to the blockwork or brick underneath gets sorted. Then a base coat goes on, followed by a top coat thrown or pressed on to match the texture of the wall round about.

The edges are the tricky part. A repair that's feathered into the old coat neatly, with a similar chip size, is hard to spot after a while. One that's slapped on with the wrong mix stands out for years, and can crack again at the join.

Why repairs show

New roughcast is a fresh colour and the old wall has had decades of rain, sun and traffic dirt on it. Even with the same sand and chips, the patch will look cleaner at first. On older houses it's sometimes impossible to find a stone that matches the original exactly. It's worth being realistic about this. If appearance matters a lot to you, ask about painting the whole wall once the repair has cured. A masonry paint over the lot gives one even colour.

Pebble dash repairs

Pebble dash, or dry dash, is slightly different from roughcast. Instead of throwing a wet mix with stones in it, the stones are thrown dry onto a wet base coat and stick there. It's common on Paisley's interwar and post-war houses, and on a lot of Erskine and Linwood.

When pebble dash fails, you'll often see bald patches where the stones have dropped off but the base coat is still there, or whole slabs of coat coming away. Small bald patches can be re-dashed. Matching the size and colour of the stones is the hard part, so bigger repairs often look like repairs. If you're unsure whether you've got pebble dash or roughcast, our guide to harling, roughcast and pebbledash shows the difference.

Cracks round windows

This is the single most common repair. The corners of window and door openings are where the wall moves most, and where the coat is thinnest, so cracks start there and run outwards at an angle. Old windows that were replaced without much care can leave gaps round the frame that let water behind the roughcast too.

A repair here usually means cutting out the cracked coat, sealing round the frame properly and making good. If the crack runs a long way, or goes straight through the wall rather than just the coat, the firm will tell you, because that's a different kind of problem.

Find the water before you fix the wall

Most patches of failed roughcast have a cause above them. The usual one is a gutter that overflows or a downpipe with a split joint, pouring water down the same bit of wall every time it rains. Repair the roughcast without sorting that and it'll fail again. Look for green streaks, dark patches or moss directly under a gutter or beside a downpipe. Our page on blocked gutters and downpipes covers what to check, and the same firm can sort the gutters at the same visit.

If you'd rather a smooth finish than roughcast, a render repair or a new render coat is another option. See rendering in Paisley. For the towns round about, see roughcasting across Renfrewshire.