can ordinary emulsion be applied straight over a well cleaned/prepared interior wall that has suffered previous damage from a leaky roof? The problem was cured long ago and the wall has been dry for a couple of years or more. The sand/cement rendering to the wall is in good condition but the staining remains. Is the stain likely to bleed through and, if so, any ideas how to stop it doing so.
Many thanks
Nick.
By 'eck, it's been a grand day.
You can but the stain will show through eventually, anything from a few hours to a day or three. To stop this you need to seal the stain in with something impermeable to water, ordinary oil based paint or a proprietary stain block.
As it was a water based stain then chances are that water based paints could cause it to bleed through Ideas to stop it well i have always found a coat or two of an oilbased undercoat seals the stains
Steve
Anything water based remains water sensitive to a degree in the finished film. Having got myself liberally splashed with Dulux "waterproof" 15 year masonry paint yesterday, I was slightly surprised at how easily the dried film washed off in the shower. As an aside, the colour match they mixed was nothing like the original (which they had discontinued), so I wouldn't waste my time on that service again.
Prepare surface, put coat of ordinary oil-based undercoat, then once dried paint with emulsion as normal.
Routine & standard practice according to our decorator.
-- Richard Sampson
email me at richard at olifant d-ot co do-t uk
That works but does mean extra work, as emulsion doesnt spread properly on top of oil based undercoat, I found. Result was needing 3 coats of emulsion, otal 4 coats instead of 2.
Stain block otoh only needs 2.
Regards, NT
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