Rendering block work. Check please!

21 Oct 2014
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West Midlands
United Kingdom
On the brink of rendering the block extension at the back and 20mm pebble dash at the front. Think I’ve got it right in my head, but want someone with a bit more experience to check my plan (that means someone who has done it once or more).

Materials : plastering sand, waterproof addy, OP cement, plasticiser.

Scratch coat 5-10mm, 4:1 plastering sand : cement, water proof additive. Wet block work first, get it on wall then scratch up.

Top render coat 5-10mm 4.5:1 plastering sand: cement, plasticiser. Wet scratch coat first

Battens set, straight edge/rule off. Let it pick up then poly float over to give final flatten

Leave 2 weeks then masonry paint

Pebble dash- same as above but swiftly dashing the pebble/gravel in an upward motion.

What could go wrong?
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I've done it 3 times!

Do you know how to rub up sand and cement render to produce a good quality finish - on the job is not the best time to find out!
I've done it 3 times!

Do you know how to rub up sand and cement render to produce a good quality finish - on the job is not the best time to find out!
Eerrrr, rub the poly float over the render after it’s picked up in a circular motion? I’m almost an expert as I’ve watched a YouTube video.....
You're all set then! I found the getting the timing right the hardest part, especially on a large area (even more so in this weather), where you may need to start rubbing up the start of the wall because it's getting too dry before you've finished spreading it on the other end.

Problem with YouTube videos is that they're all done by professionals with years of experience who make it look easy - they might have 2 or 3 hollows per metre to fill in whereas I probably have 20, they can manage the suction and have an eye for how thick to lay it on etc - I can do it, and produce a professional finish but it's a struggle.

I hope it goes well for you. If not Artex Hyclad covers a multitude of sins.
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The back of the extension is gonna be tough. An 8m long wall that needs to be flat as in the early afternoon the sun strikes nicely across which will highlight all the sins.

I was thinking tyrolene if all goes to rat sh1t.
Be realistic in your expectations, this is very hard to get right, and even if you do a really good job and don’t get caught out by it going off too quick or whatever, that back wall with the sun on it when painted WILL show variations and won’t look great if you’re a perfectionist.
In this weather you will really be fighting against the clock to float it up before it goes too dry. It’s catch 22 cos you want to take your time on the ruling off, to keep filling all the hollows and give yourself the best chance of getting it flat and looking decent once painted. Fair play to you for doing this, but just be prepared in this weather.
For what it’s worth I reckon I’d look at the bagged synthetic renders like k rend or something, next time I do it, which you finish by scratching with a nail float instead, and don’t have to paint. I can’t see how that could be harder than s&c, which is bloody hard, but I could be wrong. But if you’ve got all your materials already and you’re in the zone ready to go that’s probably not helpful.

Ps after floating it’ll have a swirly pattern caused by dragging the bigger stones around, if you want a smoother finish use a sponge (after floating) makes it look really good (relatively, until painted, you get the idea)
Pps totally agree with cdbe’s good advice above
I’ve not got my materials yet. I kind of went against K-rend types for 2 reasons. Firstly price. Seems to me almost double the cost. Secondly this no painting idea I feel is ******..... the amount of those over 55 developments going up that are all k-rend look shabby and dirty in a year - like they need a coat of paint! Defeats the object. I don’t mind every 2-3 years buying a pot of paint and freshening up.

But I do share your reservations about the sand/cement render in these warmer temps. I recon my arm will fall off half way through. Plastering the kitchen ceiling damn near killed me. And I had a hand with that.

Just to clarify.... waterproof addy in the scratch coat?
Yep, waterproof in scratch only
It’s not so much the no painting I was alluding to with the krend, more that it may be an easier route to getting a decent finish, but like I say I’ve never done it. Good luck

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