Do walls need to be primed before they are painted can be a vexing question. However, the paint companies recommend that you always prime and it is often necessary. After all, priming can provide you with added benefits and it is recommended that you apply good quality primer
on the walls before they are painted. Nevertheless, there are few situations when you can avoid priming as not all surfaces need to be primed first.
Mentioned below are conditions when you may need to prime:
Bare Wood Surface or New Drywall:
If you have a bare wood surface or new drywall to be painted, priming is always necessary. Newly installed drywall is highly porous. The bare facing papers on the drywall as well as the dried joint compound are something that needs to be primed before painting. Also, a bare wood surface is very porous and you should always apply high-quality primer before painting.
Skim Coated Drywall Surface:
Skim coat is a very thin swipe of drywall compound which is usually laid over the bare drywall. Just like the bare wood or new drywall, skim coated surface is highly porous and thus requires priming. This type of wall texture is made with a material much like drywall skim, which needs priming before painting.
Surface Previously Painted with Gloss Paint:
If the wall is previously painted with high gloss paint, it cannot hold paint well. In this type of wall, you should apply a light sanding and couple of coats of high-quality primer. Priming will make the color coat thick when applied on a previously painted wall. If you decide not to sand down the glossy sheen, you can still apply primer to make the paint coat stick.
Dark to Light Colors:
Priming is also necessary when you have a wall previously painted with dark colors and you want to apply light colors on it now. When changing from dark to light colors, you first need to apply two coats of white primer. If the existing wall color is extremely dark, you need to apply another layer of primer.
On the other hand, if you have a lighter wall and you want to apply dark colors on it, you should choose the color of the primer closer that of the existing wall color or even choose a matching primer. This reduces the number of primer layers you may need to apply on the wall.