Damp through render

[ecuk2]

Hi, we have two damp exterior walls which are causing the paint to peel. I'm definitely not an expert, but I believe it's render on top of brick.

On the patio wall (the worse of the two) it really doesn't matter that the wall is damp, but it just looks poor. I was quoted £1,000 to replace the render with render mixed with sika (waterproofer) but I'm not entirely sure that this will work and it seems expensive. I wondered about just paying someone to remove the render entirely and have painted brick, but that seems a shame.

The house wall has the same problem.. but that does need to be rendered. I have no idea where the damp is coming from, but I guess it's rising from the ground beneath the house. The only issue I have is the flaking paint. What would you suggest? Thank you!!!

 

[^woody^]

The pattern suggests you have damp rising or wicking from ground level.

Whilst the area could be repainted, or damaged render could be cut out, treated and replaced, that won't deal with the root cause.

Cut the render off (it's now salt contaminated) and replace it ensuring that the bottom line is above any DPC and formed in a bell-cast detail to cause rain to run off it.

As for your quote, it's not a water penetration problem, and render is naturally water resistant and does not need an additive for that

 

[ecuk2]

The pattern suggests you have damp rising or wicking from ground level.

Whilst the area could be repainted, or damaged render could be cut out, treated and replaced, that won't deal with the root cause.

Cut the render off (it's now salt contaminated) and replace it ensuring that the bottom line is above any DPC and formed in a bell-cast detail to cause rain to run off it.

As for your quote, it's not a water penetration problem, and render is naturally water resistant and does not need an additive for that

Thank you - that's very helpful. Do you happen to know of anyone in south west London who can do this sort of work properly? Probably not... but I may as well ask!

 

[^woody^]

LOL, no.

I'd do a bit more research and then get to know the right questions to ask.

 

[ecuk2]

After a winter to think about this I’m wondering whether it’s possible to get paint which will tolerate the damp render? There are no side effects that we can see from the damp render so it’s really more of a cosmetic issue…and cutting render for it seems a big deal. Am I making a mistake!? Thanks

 

[ecuk2]

Bump

 

[jj4091]

Going by the green algae I would guess you do not get much sun on those elevations so it probably never dries out properly. As Woody said you need some sort of break between the ground and the render other wise it will never dry. Does water pool there. Unlikely as it might be where you live I think a good frost would freeze any moisture behind the render and blow it off. If you have it done in coloured render, when you get it done, you won't have to worry about paint in the future.

 

[ecuk2]

Thank you @jj4091

I've had a go at removing the paint (tried all sorts... angle grinder, paint stripper, heat gun etc!) and have made some progress. My suggestion is to:

1. Do a bit more paint removal (but realistically it won't all come off)
2. Skim with filler to even out the surface
3. Apply Sika PVA to reduce the water coming out of the wall
4. Paint with Sandtex breathable paint

Is this a terrible idea? I'm really keen to avoid the cost of re-rendering if I can..

Thanks!