The painting and varnishing of stone surfaces improves its appearance and brings out the natural beauty of the stone. It also allows for easier cleaning and eliminates dusting to a certain extent.
Painting ordinary stone, like slasto, is relatively straightforward.
Slate is more difficult, however. Paint and varnish do not adhere to slate because of its plate-like structure which causes the paint to delaminate.
Preparation of stone surfaces
- Scrub the stone using a suitable concentrated detergent to remove dust and dirt.
- Remove plaster splashes with a cement cleaner.
- Rinse well with clean water to remove all traces of detergent, brick cleaner and salts.
- Allow to dry completely before painting.
New plaster is not normally subject to cracking initially.
- Remove dust, dirt, plaster splashes.
- Clean down generally.
Previously lime washed or distempered
- Remove to bare surface by wire brushing, scraping or washing.
Previously oil or alkyd painted
- If the paint is in poor condition, remove it to the original surface.
- If the paint is in good condition, clean the surface to remove dirt and grease.
It is very difficult to remove all traces of wax through any process of cleaning. Even the smallest traces of wax seriously interfere with the drying, the adhesion and appearance of the coatings. Therefore a previously waxed stone surface should not be painted until you have tested a small patch first and the drying and adhering of the paint proves successful.