Plaster itself was not usually made with asbestos, but the things around it frequently were: the textured coating on top, the insulating board behind it, the fire protection under it and, in some periods, an asbestos fibre added to the plaster mix. Wall and ceiling linings are the materials most often missed in a survey and most often hit by a builder, because they look ordinary and they are everywhere.
What may contain asbestos
Textured decorative coatings applied over plaster. Asbestos insulating board used as a lining, a partition or a fire break behind or above the plaster. Some plasters and screeds where fibre was added. Bitumen and adhesive layers behind panelling. Lath and plaster itself is generally a timber and lime construction rather than an asbestos one, and what sits against it may not be.
Why linings are missed
A management survey is not allowed to open a wall, so board behind plaster is frequently recorded as presumed or not accessed rather than identified. That is correct and it is exactly why a refurbishment and demolition survey exists. Work that will open walls needs the intrusive survey, and a builder finding grey board mid chase should stop rather than continue.
Identification
A sample of the actual layer in question, analysed by an accredited laboratory. The coat, the board and the adhesive are three materials and three samples. Photographs of a wall are of no use here, and the distinction that matters most, asbestos insulating board against ordinary plasterboard, is decided by density and analysis rather than by eye.
If a builder has already cut into it
Stop the work, keep people out of the room, leave the debris where it is and do not sweep or vacuum. Get the material analysed before anything else happens. Ordinary vacuum cleaners spread fine fibres, and a room that has been swept is a harder and more expensive clean than one that was left alone.
Questions people ask about asbestos plaster
Does plasterboard contain asbestos?
Ordinary modern plasterboard does not. The material to be careful about is asbestos insulating board, which was used in similar places and looks similar once painted.
What does asbestos plaster look like?
Like plaster. Nothing visible separates a mix containing asbestos fibre from one that does not, which is why the answer comes from a sample.
Is textured coating on a wall the same risk as on a ceiling?
Same material and same treatment. It is usually non-licensed work, and it must not be sanded or dry scraped in either place.