We have often been asked "How do I paint on new plaster?" and "How do I paint on lime plaster", so we thought we'd write an article to add to our FAQ pages.
Painting New Plaster
If you've just had a room plastered and you're itching to start painting, then read on. This handy guide to painting new plaster will help you avoid the pitfalls and get the immaculate finish you want.
First off, let's deal with a myth. Many people believe that applying a layer of diluted PVA glue to seal the 'plaster' is a must, but professional plasterers and decorators agree that this is a waste of time. It can even lead to a poor paint finish if there are any lumps or inconsistencies in the PVA. We follow the professionals in recommending that you apply our paints directly to the plaster wall.
Many conventional and most organic paints need to have a first special first layer applied called a 'mist coat,' made up of paint diluted with water. This helps the top coat to bind with the plaster, but it's time consuming and messy.
That's why we recommend Auro 524. Thanks to its special formulation, which includes the biogenic binding agent Repeblin, it binds perfectly to the plaster, just thin the first coat with up to 20% water and this will allow the plaster to soak in the paint properly. Once dry, apply a normal non watered down coat of the 524. It generally covers in just one coat (2 may be needed for the bolder colours)
Auro 524 is specifically designed to be used directly on new plaster, and can often get the job done in one coat.
Painting Lime Plaster
"When choosing a paint for lime plaster, breathability is the key. Just one square yard of 5mm-thick lime plaster can contain up to half a litre of water.
It can take over six months for the plaster to fully dry, but, if your paint is porous and breathable such as Auro 524 then you can paint much earlier, as the water vapour isn't sealed in.
If you're painting lime plaster, Auro 524 is once again the best choice, as it is both fully breathable and emission-free, meaning there's no risk of a reaction between the chemicals in the paint and the drying plaster.
Once you've chosen your paint, make sure you pick the right tools for the job. Since new plaster is a smooth, low-friction surface, a cheap or dilapidated roller can slip and cause an uneven finish. As you're applying the first coat, you may notice slight blemishes or bumps which weren't apparent on the raw plaster.
If you do find any unsightly ridges or lumps, don't panic. These can be sanded down with fine sandpaper (make sure you wrap the sandpaper round a plane surface to ensure you get a flush finish), and immediately painted over.
If you find any gaps or recesses, these can be filled with wall filler, sanded, then touched up with paint.
So there you have it: If you're planning on painting over new plaster, don't PVA, make sure you save yourself time and effort by using a paint which doesn't need this solution, and make sure you have the right tools for the job.