A lot of the UK housing stock has some degree of cement and sand render applied to either a section of the walls eg top half or  covering the whole wall.  Usually the reason was to protect porous brickwork from the British weather and in this instance the typical finish is a rough texture finish.

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This was achieved by adding pebbles or stone chippings as an aggregate into the top coat mix or by merely applying a thicker top coat. The different finishes will usually have the same first scratch coat or backing coat of typically 6 parts sand to 1 part cement and this was trowelled on first and left to set after having its surface scratched up as a key for the top coat.

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On the older heavier pebbledash and stucco finishes it was also standard practice to mix in some caustic lime to help the render mix firmly bind with the brick surface by in effect burning the render mix into the brick face. This is one major reason why removing old sound pebbledash is very difficult and often results in pulling the underlying brick face off the wall as it remains firmly attached to the back of the pebbledash.

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By the 1970’s design tastes had changed away from the heavy texture of stucco and pebbledash to a lighter texture and this led to the introduction of Tyrolean render in large quantities. This is the weakest of all renders and the Tyrolean top coat is really a watery slurry coat using fine aggregate which is applied via a container with a handle at the side. The handle is turned and sprays the tyrolean mix onto a prepared wall where  it then dries and sets. This method is also the cheapest finish and least durable.

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By the mid 1980’s smooth or flat sand and cement render came into fashion and is still currently the most popular type of render today especially on block built properties. It has the appearance at first sight of a plaster flat finish which is then painted and re-painted every 5 years or so .  It is often applied inappropriately and any walk down a suburban street will highlight lots of cracked and repaired flat rendered walls and when the sun is on such a wall it is common to see a lot of trowel scarring.

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Whilst pebbledash etc was probably the best option when bricks were at a shortage or a building was block built technology and expertise has moved on since the 1930’s. The current array of acrylic, silicate and resin coating systems are precision made in high tech manufacturing plants and have vastly improved performance characteristics than the old cement based renders and most need no maintenance in years to come.

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If you would like more information please  Call 08456 345 866 and we would be delighted to hear from you.

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