Drive through any street in Stirling and most of the houses you pass will be roughcast. It has been the standard external finish in Scotland for well over a century, and for good reason. Here is what it actually is, why it suits our climate, and how to decide whether it is the right choice for your house.
Roughcasting is an external wall finish where small stones or chippings are mixed into the final coat of render, then thrown onto the wall while wet. In Scotland you will also hear it called wet dash or harling, which is the traditional lime-based version seen on older stone buildings and castles. The result is a textured, slightly lumpy surface rather than a smooth one.
It differs from dry dash, where the chips are thrown onto a smooth wet render coat and stick to the surface, and from modern smooth or thin-coat renders. With roughcast the aggregate is part of the mix itself, which makes the finish dense and hard-wearing. A typical job involves a scratch coat, sometimes a second levelling coat, then the roughcast coat applied on top.
The main reason roughcast dominates in Central Scotland is driving rain. Stirling sits in one of the wetter, windier parts of the UK, and rain here often arrives sideways. The textured surface breaks up water running down the wall and sheds it away from the face, rather than letting it sheet down and find its way into hairline cracks the way it can on a smooth finish.
It is also forgiving. Smooth render shows every ripple in the wall beneath and every fine crack that appears over the years. Roughcast hides minor imperfections and small movement cracks far better, which matters on older masonry that is rarely perfectly flat. Done properly with the right mix, a roughcast finish should last 30 to 40 years or more with very little attention beyond an occasional wash down or repaint.
The honest answer is that it is not for everyone. Some homeowners simply prefer the crisp look of a smooth or thin-coat render, particularly on modern builds or extensions, and there is nothing wrong with that provided the detailing around sills and copes is done well. Roughcast is also harder to patch invisibly: matching the texture and chip size of a 30 year old wall takes skill, and a poor patch will always show.
The bigger issue is the wall behind it. If your house is traditional stone built, typically pre-1919, it needs a lime-based harl that lets the wall breathe. A strong cement roughcast on old stone traps moisture, and that is a common cause of damp inside older properties around Stirling. Likewise, if existing roughcast is hollow when tapped, or blown in patches, rendering over the top is a false economy. It usually needs stripped back and redone properly.
As a rough guide, reroughcasting typically runs from around £60 to £100 per square metre including stripping the old finish, so a full semi-detached house often lands somewhere between £5,000 and £9,000. A small gable or single elevation is obviously much less. These are ballpark figures, not quotes, because every wall is different.
The main things that move the price are scaffolding access, how much old render has to come off, the condition of the masonry underneath, and whether you need lime rather than cement. Repairs to cracked or eroded stonework before coating can add cost but are worth doing once the wall is exposed. A written quote after someone has actually tapped and inspected your walls is worth far more than any online figure.
Broadly yes, harling is the traditional Scottish term, though today it usually refers specifically to the lime-based finish used on older stone buildings. Modern roughcast is normally a sand and cement mix, which suits most 20th century and newer homes.
Sometimes, but only if the existing coat is sound and well bonded. If it sounds hollow when tapped or is cracked and blown, it needs stripped off first, otherwise the new finish will fail along with the old one.
Yes, most roughcast in Scotland is painted with a breathable masonry paint, typically every 8 to 12 years. Painting also lets you refresh the colour, since the natural finish weathers to a grey over time.
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