At some point in time you’re going to come across the common problem of a stained surface, be it from damp, nicotine or any number of causes, on walls and ceilings.
As you’ll find, simply painting over the stain doesn’t always work as the solvents in the paint you’re using cause the stain to migrate through to the surface. The result being that no matter how many coats you apply the stain still comes through.
The reason for this is actually quite simple – some stains are water-based and some are solvent-based, the same as paint. So if you use a water-based paint on a water-based it’s going to keep coming through. The same applies to top solvent based paints and stains.
The solution, therefore, is to use a different based paint to the stain you’re trying to cover.
So for waterborne stains and nicotine a solvent based (oil-based) paint will usually seal it. And for solvent-based stains such as crayon marks, pen marks, etc a water-based paint will usually do the trick.
And, if you’re not sure what the stain is – a spirit of shellac based primer can often be the answer since it will not allow either to migrate.
Just to complicate matters, because of the move towards eco-friendly water-based paints you will find a lot of general-purpose products which are water based. Although effective against oil-based stains they can be less so with water-satins and nicotine – so only use these if the problem is minor.
You’ll find all manner of different solutions labelled as ‘stain-blocker’ but below are the most popular for every situation…
Please bear in mind that when using spirit or oil-based sealers, it is essential you ensure the room is well ventilated during application and for a few days afterwards – particularly when treating large areas.
If you have any questions about which stain blocker to use please get in touch via the contact page.