Powdery Surface
Common causes and solutions to prevent and fix a powdery limewash finish
Q. Why is my limewash finish powdery and rubbing off on my hands?
Powdering usually occurs when limewash paint is applied too thickly, preventing it from curing properly. This causes the lime to ‘bloom’ on the surface, leaving white patches and making it powdery, so it comes off easily when touched. For best results, apply limewash in thin coats using an absorbent bristle brush. Spread the paint out as far as it will go, without overworking it. Curing takes about two weeks, so avoid rubbing the walls during this time to prevent marking.
Mineral-based limewash, like Bauwerk Colour, requires a moderately absorbent surface. When a surface is non-absorbent or absorbs too little, proper preparation must be undertaken to create the right conditions for the limewash paint to penetrate. If painting over a sealed or non-absorbent surface, such as a wall previously painted with standard acrylic house paints, lime blooming is more likely to occur, as it is more difficult to avoid over-application of limewash. We recommend using Bauwerk Prep Coat as an important step in surface preparation when limewashing previously painted or sealed interior wall surfaces. For external surfaces that have already been painted or sealed, we recommend applying a fresh cement-based absorbent thin coat render (used externally or internally) to create a surface for lime wash paint to penetrate.
It is best to reapply Prep Coat if you have already done 4 or more coats of limewash paint.
4 Common Causes for a Powdery Limewash Finish
Q. How do I fix my walls that show white powdery patches ?
To resolve powdering or white patches from over-application, simply wait 24 hours and apply an additional thin coat of Limewash paint.
Tips + Tricks
- When applying the paint to a wall, have a look side-on from where you have applied. With the glare you will be able to see if there are areas with too much product.
- Make sure your brush is in good condition – not too dried out and clean of old paint etc.
- Be mindful to have the "right" amount of paint on your brush for the area or cloud you will be painting. Too little will also make it difficult to spread before it dries.
- When painting your clouds make sure to paint until it feathers out on the edges. This is a good indicator that the paint has been stretched. This with the first tip will help to keep the coats consistent.
We would also suggest having a look at our YouTube tutorials, especially any that mention application over Prep-Coat.