Leaking pipes can sometimes cause water stains on wall or ceiling surfaces painted with lime wash paints. Whilst in most cases the paint itself will not blister or peel off, the water may dissolve materials that can cause staining of the coloured finish.

Our recommendations to deal with a water leak stain is as follows:

Apply at least two coats of a water based, low VOC primer with the specific ability to stop water stains (among other things usually). It is important that the Primer you choose is not solvent based, as that would cause bubbling. Apply from corner to corner, not just across the stain.

Allow adequate drying time between all coats and follow the manufacturers instructions.

You may want to test the effectiveness of the primer with a simple water test to see if the stains have been blocked.
Here you find the instructions for the water test.

Then apply one coat of Limewash Prep Coat in the usually recommended way and follow with two coats of lime wash paint.