Stained and previously damp wall

[Steve Kramer]

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 dry.

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 ?

Thanks

[Andrew Gabriel]

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.

[AJH]

A plasterer suggested SBR to me to treat a similar situation

[Mike P the 1st]

On Sat, 19 Feb 2011 01:13:29 -0800 (PST), AJH gently dipped his quill in the best Quink that money could buy:

I am pretty sure it would be difficult to paint over SBR and get a good result.

Just to clarify .. PVA will always return to a wet state when moisture gets on it. SBR will stay hard.

Mike P the 1st

[Steve Kramer]

Thanks guys 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 coats. Cheers

[Mike P the 1st]

On Sun, 20 Feb 2011 22:34:06 -0000, "Steve Kramer" 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.

USES:

- 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

[Steve Kramer]

"Mike P the 1st" wrote in message news: [e-mail]...

Thanks Mike