Render for garden wall

cyclonebri1

Anyone have a recipe for sand cement render for a garden wall?

Could use a standard say 4 or 5 to 1 sharp sand cement mix, any stronger than that and it tends to crack on setting in my exp, but is there a better option given there will be no damp course and the wall will have planters built in so wet on the inside too?.

Additives etc?

tony6403

We used acrylic render on an extension. It came in 25kg bags and just required water to be added - the job was sub-contracted out so can't give details. Really strong stuff ,worth doing a bit of googling.

cyclonebri1

tony6403 wrote: »

We used acrylic render on an extension. It came in 25kg bags and just required water to be added - the job was sub-contracted out so can't give details. Really strong stuff ,worth doing a bit of googling.

I had a look at that but to be honest it appears to be a 2nd coat over standard sand cement render 1st coat. Probably great as a resilient finish but we have that covered. The house itself is done in an expensive resin based masonry paint that we intend to match.

In the absence of any other suggestions I will go with a 4:1:1 sharp sand cement lime mix????, or maybe 3:1:1?

Furts

I know you are a practical, experienced man. But for the benefit of others it is not good building practice to render garden walls. Unlike a house, a garden wall can get wet from both sides. Also it is more subject to driving rain and freezing air and winds. Frequently the moisture in rendered walls is trapped and this spalls the render in freezing conditions.

This does not mean you cannot do it, nor a wall in sunny Cornwall or a sheltered spot is going to fail.

tony6403

Bri - the acrylic render went straight onto medium density concrete blocks .
I today took a slight diversion to see how the rendering on that extension looked after we did it 5 years ago. No defects at all.
If acrylic doesn't appeal, maybe those fibre additives which claim to prevent/reduce cracking when setting would be worth considering.

cyclonebri1

Furts wrote: »

I know you are a practical, experienced man. But for the benefit of others it is not good building practice to render garden walls. Unlike a house, a garden wall can get wet from both sides. Also it is more subject to driving rain and freezing air and winds. Frequently the moisture in rendered walls is trapped and this spalls the render in freezing conditions.

This does not mean you cannot do it, nor a wall in sunny Cornwall or a sheltered spot is going to fail.

Thanks Furts, Yes I am fully aware it isn't good practice to do this, I should have pointed that out for the benefit of others not in the know.:T:T

I think you can tell from the tone of my question that it isn't something I would normally do or advise, never ever done 1 before for just the reason you mention;)

But I have an insistent daughter who is just having this wall built and it seems I'm involved, .

I've seen many done and many fail too, even worse as I pointed out is that this is a fair length wall which is half raised bed so as I said it definately will be wet both sides.

2 years ago we had the new extension rendered and we painted it with a resin based masonary paint, name escapes me, but dam expensive stuff, so 1 side will get a decent proofing.

I have already said in my view it isn't a long term bet, but you know how they are today, so long as it looks good and matches the house for a few years all is great.

Tony, all the info I found said 2 coats, 1 standard and 1 acrylic, but it's a bit academic as I couldn't seem to find a small scale supplier anyway.
The fibres you mention are great in concrete for the reason you mention, that was the reason I mentioned hydrolated lime in the post earlier, that serves a similar purpose.

Given all the above and the fact that I will likely have to do this anyway that may be a useful idea, strong mortar to ensure no spalling and fine fibres, (I know they come in several grades), to prevent cracking before the strength has developed.

blackshirtuk

Maybe you could swap the sharp sand for plastering sand?

Supposed to stick easier and give a smoother finish.

http://www.wickes.co.uk/plastering-sand-major-bag/invt/224666/