Garage Wall

[browndmb]

The wall is plastered and painted but cracks have appeared and the paint is flaking off. Any help with how to tacle this problem would be appreciated. I wonder if just painting over will do the trick or will it have to be sealed.

Another question is --can I paint over sealant. Around the upstairs window has become black in bits and bleaching has no effect so thought a wee touch of paint would make it more presentable

Thank you

[KARL]

Regarding the garage wall, are you certain it is plastered and not rendered ? The first thought would be that moisture could be coming through the wall from the other (out-?) side. If it is plaster then the prognosis is poorer than if it is render, unless it is plasterboard with a gap behind it.

You certainly can paint over sealant, but the results will depend on the type of sealant. If the sealant is silicone then no paint will remain on it, in the long run no paint will stick to to it. If it is any of a number of types which "bleed" into paint, then the paint will gradually change colour (mostly darken). Acrylic sealant is one that paint will stick to fairly well and not discolour significantly. There is also a sealant called CT-1 which can be overpainted successfully and there are a few others (but not widely used) which have a similar performance. Your description suggests that your example is likely to be silcone, in which case if you want to give your efforts the longest life expectancy you might consider putting on a thin coat of CT-1 over the existing material or even remove the existing and start again.

[Old_Geezer]

It's a posh garage that has the inside plastered.

Cracks have appeared ? If in the wall itself maybe you have the issue I have with different materials having different rates of thermal expansion. In any case you might wish to fix the cracks first before doing anything else.

[The Builder]

As an alternative to Karls's post, you could try this..........

http://www.screwfix.com/p/no-nonsense-sealant-remover-100ml/88987?kpid=88987&cm_mmc=Google-_-Product%20Listing%20Ads-_-Sales%20Tracking-_-sales%20tracking%20url&;gclid=COHc4ee7o88CFYgK0wodf7wG7Q

Try it to take off the outer surface layer of the blackened silicone. If that isn't successful, cut out as much of the sealant as you can, and re-seal using a mould-resisting "sanitary" silicone sealant.

As OG says, is it sand & cement render, or a Thistle skim finish?

What's the wall construction? Is it single skin brickwork? If so, then there is damp penetration from outside.