Plastering Question

What is the correct mix for rendering the outside of a building ready for pebbledashing, do you put lime in.

the existing rendering that was done has blown in places and the cement looks to have been mixed wrong. It is important that we get it done right this time. thanks

3 Answers

Best Answer

The correct method for pebbledashing is 3.5 to 1. (3.5 plastering sand to 1.0 cement) for the first coat(scratch coat)including feb/addmix and waterproofer. The waterproofer helps control suction.
The top coat is 4 to 1. Always make the scratch coat a stronger mix. NB. Before applying the top coat soak the base coat at least three times with clean water. This will enable zero suction and ensure the finished job has no 'dry ' joints which is good for larger elevations.

Answered 23rd Feb 2012

Woolton Plastering & Rendering

Member since 9 Oct 2010

Hi the mix i always use is 4 level buckets or rendering sand to one level bucket of cement don't put lime in as this creates suction! you should add a waterproofer eg: freeflow. Also you shouldn't have any rendering done on hot sunny days when the sun is on the wall as this will bake the render and it will fall off.

Answered 22nd Feb 2012

mark rayworth plasterers

Member since 17 Feb 2012

hi there i never use lime for dashing just do a mix four sand one cement should be fine. some times it blows because the first coat u do wasn't lefted for a good time to heel or just got not enough cement when it was done..

Answered 22nd Feb 2012


Member since 30 Nov 2011

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