Hi - the bad weather last winter has caused a fair bit of damage to the bottom of the render on my exterior wall where it meets the pavement. (Did even more damage to the pavement tarmac but the council have taken care of that!) Basically, it's come away in places - mostly strips a few inches high. Is this something I can repair myself or do I need to call in the professionals? And if I can do it myself, what should I use? The render is painted black at that level so I'm not worried about it looking absolutely perfect, I just don't want damp or whatever to get in and cause more damage this winter. If it's of any relevance, my house is an old stone-built cottage which probably wasn't originally rendered. The render itself is smooth, not pebble-dashed.

Also, the exterior paintwork has bubbled/flaked in the odd patch elsewhere - nothing to do with the above problem. I was told I just need to scrape away the flaking paintwork, apply a sealant and repaint. Is this right? What kind of sealant?

Thanks for any advice.

Do you mean the black bit underneath your wall, ( ie the damp course)

Where the exterior paintwork has bubbled above ( what I think your talking about the damp course), yes, just scrape it back, even if it means going back to the original rendering.

You could use a stabilser/sealant, but that is normally for new rendering/pebbledashing, but I suppose if you scrape it back it would reveal a new/bare surface.

What I would do first is, is to scrape it back like you have been advised, then instead of forking out loads of money on stabilser, which can work out expensive, I would paint over where you have scraped off off with a very watered down coat of paint, when I say water down, I mean instead from the can, pour some of your paint into a utensial/container, add about 25% of water, ( doesnt matter if its too thin), then paint that on the bit where you have scraped off, leave to dry, then go back over it again, but this time with the same paint, but add a bit less water to the mix, ie 10-15%, I promise you it wont flake off, unless there is a serious damp problem coming through the walls.

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I would rather want something I dont have, that have something I dont want

if it is indeed render down to the pavement surely this would be bridging any DPC in the building? and shouldn't be there because of it.

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“He who asks a question is a fool for five minutes; he who does not ask a question remains a fool forever”
Abingdon Plasterer

Sounds like the black stuff is a bituminous mastic/paint, was quite common.

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how does that stop moisture getting in from below mate? curious how this can be good practice, maybe it isn't and that's why it's no longer done.

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Abingdon Plasterer

Stops penetrating damp, and rising damp can't get past the DPC if it has one.

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so there's a DPC in the render too to stop it bridging?

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“He who asks a question is a fool for five minutes; he who does not ask a question remains a fool forever”
Abingdon Plasterer

Hi folks - thanks for those taking the time to reply. The black is paint, plain and simple. When we moved in the render was painted yellow and terracotta, and we had it all repainted white with black detailing round the doors and windows. The painter suggested we also paint a black border about a foot or so high round the base of house on the side that backs onto the street so that dirt wouldn't be so obvious.

As for a DPC, I honestly have no idea if the house has one!!! The render doesn't quite meet the ground round three sides of the house, where it's bordered by gravel. But the street out back is at a higher level and the render goes all the way down to the tarmac. As it does on several other houses in the street. I understand the reasoning behind DPCs but I actually don't understand how/where you would finish off the render so as not to bridge it. Maybe I have my terminology wrong so if I can find the time to take a picture in good light and post it on here, I'll do so.

that'd be good, housewife

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“He who asks a question is a fool for five minutes; he who does not ask a question remains a fool forever”
Abingdon Plasterer

Images attached:


This one shows the corner where a side wall (actually the side of our adjoining garage) is unrendered


The brick/mortar lines are fake - just scribed in to give the impression of brickwork.

The render is painted black at that level so I'm not worried about it looking absolutely perfect, I just don't want damp or whatever to get in and cause more damage this winter. If it's of any relevance, my house is an old stone-built cottage which probably wasn't originally rendered. The render itself is smooth, not pebble-dashed.

its not necessarily damp/moisture getting in thats the real problem...its that it cant get out.
the real issue is the fact that (and I know there are millions of them) the wall shouldn't of been rendered in the first place ....at least not with the material that is probably used there ...( CEMENT ) ...The render should not go all the way to the tarmac,and is the biggest cause for the delamination.

If you have to have render there for aesthetic reasons now...myself I am going to replace it with hydraulic lime....and be prepared to fix it every few years ...irregardless of the material choice....(cement or lime)

best method is to do away with all the render and redo with lime ...or ....hack off the bottom 6-8 inches and leave the stone exposed...unsightly but any material placed tight to the tarmac will eventually fail ...

*Sigh* .... I don't know who/when/why it was rendered. Perfectly good stone wall under it all! I would love to be able to afford to have the whole lot taken off. But as it is, I'll have to repair it as best I can and will seek further advice about chiselling off some at the bottom. Lime is pretty nasty to work with though, isn't it? Maybe I'll try palming this job off onto someone who knows what they're doing, then! Thanks for the advice.