Ceiling after damage

On June 6 this year, a section of ceiling plaster in the Labassa Drawing Room was found to have detached and fallen to the floor. The areas above were inspected for leaks and none were found, but investigation of the damaged plaster showed that there were two types of plaster present in this area.

Ceiling before 

The damage which has occurred in the drawing room can likely be attributed to a repair which was completed using a mix made of gypsum and sand, instead of a traditional lime (as calcium oxide) and animal hair. This mix is completely different – heavier and more rigid, which is why it has come down with no clear signs beforehand.

Difference between original plaster and previous repair

Works have now commenced to remove the remaining sand and gypsum plaster to ensure that the ceiling is safe. This is mostly what has already come down but an image from the 1980s show a wider area which will be inspected. The timber lathes which the plaster attaches too are all in-tact and secure so the plasterer will apply a scratch coat of lime, water and hair (we will try to get natural but may need to be synthetic) to stabilise the ceiling.

Once the scratch coat is completed and carbonates (hardens) it will have secured into the back of the timber lathes as shown in the image below.

Rear side of of timber laths showing how the plaster attached to the ceiling

This damage highlights the importance of using compatible materials when making repairs and supporting traditional skilled practitioners to do so. 

Please support our Heritage Services Directory by spreading the word and encouraging heritage practitioners to list and reach out to [email protected] if you are a practitioner who would like to learn more about the use of lime in traditional buildings.