As a professional painter, chances are you've come across more than your fair share of water stains.
Often DIYers will attempt to cover these stains with coats and coats of paint, but they always come back.
So, what's the best way to deal with this persistent problem?
Firstly, you must identify the cause of the problem and make any repairs necessary to prevent reoccurrence.
You are then ready to paint over the stained area.
Many professional painters recommend using a solventborne paint to banish water stains once and for all.
This type of paint will effectively "seal" the stain and prevent it from seeping through your handiwork.
While water-based paints are preferred by DIYers because they're easier to clean up and dry rapidly, many professionals still like solventborne paint.
Before you begin, ensure the surface you intend to paint is completely dry and treat it with some form of anti-mould solution, such as Resene Moss & Mould Killer.
If you've spent a lot of time with oil-based paints in the past, you'll know that they can leave an unpleasant odour behind.
You can actually eliminate this by keeping a small cup of white vinegar in the room with you while you're painting. It may sound ridiculously simple, but it really works!
Make sure you also paint with all the doors and windows open, if possible, as this will help to ventilate the space.
We also recommend using a sealer, such as Resene Sureseal, which is formulated to block off existing water stains, before you apply an undercoat.
Resene Sureseal is designed to penetrate and bond old surfaces together. It will also make them relatively waterproof. It also comes in a lower odour formulation, however, you still need to open windows and doors to ensure the paint cures properly.
It should be noted that one coat of this sealer will usually not be enough to combat excessive staining.
After you locate and remove whatever caused the water stain in the first place, apply a minimum of two coats of Resene Sureseal to the surface. Then finish with two coats of a solventborne, low-odour finish such as Resene Room Velvet or Resene Ceiling Velvet, which gives further insurance against bleed-through of water stains.