What is roughcast?
What is roughcast? |
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Roughcast, also known as ‘wet dash’ is a type of finish applied to exterior walls.
It consists of small pebbles, shells or stones added to a cement mix, before being applied to the wall. Lime can also be added as this helps the mix to ‘move’ with the wall during temperature differences and is therefore less likely to crack. |
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Once applied, roughcast dries into a tough long-lasting coat which gives protection to the brick from the weather elements and can last without having to re-work for decades. | |||
Texture or finish |
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Because roughcast is not premixed, the user has more control and choices over the finished appearance. | |||
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Different types of stones or pebbles can be added to alter the texture and finish of the mix; in Tudor times, coloured glass was sometimes added for effect! | |||
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Roughcast can be painted over with whitewash or a good external paint if required. Most jobs are mixed in a specific way (texture and colour) so no further work is required. | |||
Grain sizes |
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Larger stones/pebbles can be used, but 6-8mm (0.2-0.3″) gravel/stone chips are the ‘norm’ and it’s advised not to go bigger than 10mm (0.4″) as too big a size can weigh too heavy, causing ‘sagging’ when drying and could be extremely tiring when applying by hand!
There may not be a choice, however, if you need to patch or ‘match-up’ an area of wall which has previously been roughcast with pebbles or stones over 10mm in size. |
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