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Solid Concrete Appearance on Concrete Block Wall. Advice on How to Achieve it?

  • 09-01-2023 12:24pm
    Registered Users Posts: 1,487 ✭✭✭


    We have raised (circa 80cm) planters all around a new house we're building.

    We're going to build the ones at the front with formed/poured concrete to hopefully achieve a look a bit like here:

    Now we'd like to do the same out back but unfortunately the walls have already been built from concrete blocks like this:

    So we're looking for a way to get these walls out back to look as close as possible to the poured ones at the front as simply/cheaply as possible.

    What I think would be the best option if possible would be to add a layer of poured concrete to the front of the walls, ie put boards up to form a mould and pour 50mm of concrete all around. I know it can be difficult to get concrete to stick to concrete but I think there is some kind of additive/adhesive that you could add to the concrete to help with this. Perhaps you could put screws or similar into the block to give the concrete somthing to anchor to also. This would probably be my preferred option but I'm not sure how doable it is?

    Other options might be to try and use a render that has a concrete look/finish like this:

    But I suspect there's a pretty good chance this will wind up looking a bit crap in real life and if it involves some niche product will be very expensive.

    A final option might be cladding the wall in cement board a bit like this:

    This would probably be cheapest but again there's a very good chance it would look crap/not like real concrete would.

    Anyway if anyone has any advice/suggestions on how we can achieve what we're looking for that would be great.



  • Registered Users Posts: 38,781 ✭✭✭✭Mellor

    Trying to cast a 50mm layer around a wall will not give a great result. It's too narrow to ensure consistent fill, so you'll end up with a low grade concrete finish with lots of blowholes, and probably some honeycombing.

    I'd be more incline to go with a microcement render. Done properly this can look very good.

    The last image above doesn't look like a cement board to me. There's no fixings. If you use FC boards, you see the fixings. You could try direct sticking I guess.

    The ideal material would be a GRC panel

  • Registered Users Posts: 1,487 ✭✭✭blobert

    Thanks very much for the reply.

    I wonder if we went with a thicker layer if it would have better results. I still think in theory that's likely to give the best finish.

    Funnily enough I had looked at those GRC panels previously. They are pretty pricey at about £120 a m2 and that was 1.5 years ago.

    I figure by the time they'd put them in place you'd be talking about €200 a m2 which is pricey enough there is probably about 40m2 of wall to do.

    The cement board would be a lot cheaper at €15 per m2 though obviously it might look rubbish. I might get some to try it out.