How long should I wait before painting?
After painting a new surface, nothing would be more disappointing.Knowing how long plaster takes to dry is important.
New plaster needs to be cured and dried before it can be painted.The time it will take to dry depends on the thickness of the plaster, the temperature within the building, and the amount of ventilation available.
After the introduction of a chemical damp proof course, the plaster system used will include removal of the old plaster back to stone or brick, and 2 backing coats of sand and cement prior to the final plaster skim.
This system is carried out to replace plaster contaminated by hygroscopic salts, which will occur due to the action of rising damp, and will take considerably longer to dry out and cure, depending on the thickness of the masonry and the rendering/plastering system.If you have any concerns about damp, you should seek professional advice from a damp course specialist.
The drying times will be quicker if the plaster has been used to finish new plasterboards, or cover up/encapsulate artex.
The introduction of a dehumidifier and opening windows and doors will help to improve the drying out of the new plaster.
Low background heating is preferable to turning the heating system up high, which can dry the plaster out too quickly and cause cracking.
New plaster will have a thin layer of dust on the surface when it is dry.Before applying paint, brush this off.When the plaster is cured and dried, it is important that a thin coat of a non-vinyl emulsion is applied.
The mist coat is used to form a key or primer prior to the application of the proposed paint system.The mist coat should be applied evenly.
Minor surface filling may be required following the mist coat.The plasterer may have had difficulty finishing due to getting trowels into tight areas.If you fill and abrade, mist coat any filled areas.
It is better to mist coat in the same colour as the final coats to help build up to full opacity, as it will be more convenient.
The plasterer may have over trowelled or polished the plaster, which could be a problem with applying paint to new plaster.The mist coat will sit on the surface of the new plaster and not soak in to form the key/primer.To allow the paint to soak in, it will be necessary to thoroughly but lightly abrade the surfaces.
Don't scratch the surface too much, as the scratches will show up after the final coats have been applied.
The surfaces are ready for the final paint coats after the successful application of mist coats and filling/light sanding.
A minimum of 2 coats will be required to achieve full opacity and should be applied as evenly as possible, using a clean medium pile roller head.If the paint is very thick, mixing in half a cup of clean water will help the application to be easier to apply, and reduce patching to the final coats.
New plaster is painted on a regular basis by the decorators at Wall2Wall.If you would like to discuss painting new plaster, please call us.If you require an obligation free quotation, we are more than happy to give it to you.