Cement Render

[VxDuncan]

The kitchen extension in my house was built by idiots (previous owner), and quite frankly the finish on the render is terrible, with trowel marks all over. No where near smooth. I can do a pretty good job of plastering inside and wondering if it's possible to skim the render in the same way you'd skim an internal wall? I really don't fancy cold chiselling the lot off (and the associated brickwork damage, battening out, floating etc.), if it's possible to skim. I guess I could pressure wash it clean and have a go at skimming it? What do we think?

[mrmaggit]

Assuming the render is sound, wash all the surface dirt off, prime with SBR (not PVA!), or Rendaid, and render with some thing like Weberpral M. I'd check with Weber technical first, though, just to be safe.

[dickymint]

mrmaggit said:

Assuming the render is sound, wash all the surface dirt off, prime with SBR (not PVA!), or Rendaid, and render with some thing like Weberpral M. I'd check with Weber technical first, though, just to be safe.

mrmaggit said:

Assuming the render is sound, wash all the surface dirt off, prime with SBR (not PVA!), or Rendaid, and render with some thing like Weberpral M. I'd check with Weber technical first, though, just to be safe.

Does He have to do this twice?

[VxDuncan]

dickymint said:

Does He have to do this twice?

Two coats?

Thanks for the advice Mr M. I'm beginning to think it's probably better not to try and bodge it, as I'm a bit concerned it might not key properly into the old render. I think I'll get it re-rendered instead, once I've built up the courage to get the old stuff off!

[B17NNS]

I'd have my doubts about it keying properly personally plus a very thin skim coat of render will dry out really quickly and probably just drop off.

The only way to do it properly is hack the lot off and renew with a couple of coats sand and cement.

[D14 AYS]

B17NNS said:

The only way to do it properly is hack the lot off and renew with a couple of coats sand and cement.

^^^^^ What he said

[mrmaggit]

dickymint said:

mrmaggit said:

Assuming the render is sound, wash all the surface dirt off, prime with SBR (not PVA!), or Rendaid, and render with some thing like Weberpral M. I'd check with Weber technical first, though, just to be safe.

mrmaggit said:

Assuming the render is sound, wash all the surface dirt off, prime with SBR (not PVA!), or Rendaid, and render with some thing like Weberpral M. I'd check with Weber technical first, though, just to be safe.

Does He have to do this twice?

Sorry Dicky, but IT have been playing about and all my posts have been duplicated, and now PH has been removed so I can only now post from home.

[mrmaggit]

Weber would probably recommend the removal of the existing render (as I would), but it may just be sound, you never know.

Coverage on Cemrend is 1sq.mtr/bag at 16mm thick, bags are about ten-twelve quid each plus VAT IIRC (don't forget I'm at home now), just to give an idea of cost.

[sparkythecat]

Would it not be possible just to re-finish the existing render by smoothing it using some sort of 'sander' ?

[B17NNS]

sparkythecat said:

Would it not be possible just to re-finish the existing render by smoothing it using some sort of 'sander' ?

Nope.

Next.

Good advice already been given. If the background is sound (not blown) and a good key is achievable then it would be acceptable to render over the render but it would still be a case of a scratch coat followed by a second coat rubbed up.

If the background is in anyway dodgy the only route to a good job is to hack it off and start again.