Hi I have to paint a wall in a bedroom which for a few years was damp and
stained with mould etc from a leaking chimney.
The damp problem has been fixed now and as far as I can tell everything is
A builder said PVA it first before painting but I think damp proof paint and
stain block paint should be OK.
The plaster is OK apart from a bit of filler needed which I will do.
Any ideas or further suggestions ?
PVA isn't a very good idea. It can be hard to paint over with
some paints. Use a proper stain block, as per it's instructions.
People sometimes use a gloss undercoat as a stain block, although
that was back in the days of oil based high volatiles gloss paint
(don't know if current gloss undercoat will work).
You shouldn't need any protection against damp coming through the
wall if it's been properly fixed and allowed to thoroughly dry out.
(IME, masonary inside takes about 1 week per inch of thickness to
dry out after removing the cause of the damp.) All you are after is
something to stop the wet paint pulling existing stains out into
the new paint surface, whih is what the stain blocks should do.
[email address is not usable -- followup in the newsgroup]
It seems generally that PVA is not a good idea.
What is SBR ?
The stain block seems to be the way to go.
I have used undercaot or gloss before to prevent stains and both have been
successful though undercaot is easier because it dries quicker. It's good
for blocking felt tip and pen etc on walls that your kids have drawn on.
I will go for the stain block paint and hope for the best. Maybe a couple of
gently dipped his quill in the best Quink that money could buy:
SBR is a white styrene butadiene emulsion used to improve the
properties of cement renders, screeds and mortars. It is also used in
conjunction with Construction Chemicals Tanking Slurry as a priming
coat or tight render basecoat. Used with Sulphate resistant cement it
will resist the movement of salts with in wall.
- High strength floor screeds.
- Patching and repair mortar.
- Thin section screeds.
- As a bonding bridge for renders and Waterproofing.
- Waterproof renders and screeds.
Mike P the 1st
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