sand cement

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spunky

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What's the best way you all go about traditional sand cement through a machine? Can you spray one coat in one coat if you dub you're bells out before you drop an elevation or is it 2 passes and still floatable? or is cpi the best route and do they do different bags per coat and any idea of prices?
 

spunky

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Is that 2 seperate coats after curing between coats or 2 quick passes same day and is it still floatable?
 

plaster man

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i never tried to do to in the one day with machine u have to spray sand and cement very wet so its hard to build it up the one day if u know what i mean
 

martinemj

Well-Known Member
i use cpi sometimes but spray scratch coat and then 5 - 7days later 2nd ..

use it just as i would if hand apply
 

martinemj

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the cpi general render is just a basic s c in a bag not one coat...
not tried an i section on it ...

if you need a sc one coat then weber ocr is best bet ...
 

spunky

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Can you spray it in one coat and rub it up though, what tools are you using to flatten and scratch with?
 

grump

Member
CPI is nice stuff. I helped nick out on a job, I believe he used the same stuff to as scratch as top coat. Usual procedure scratch an leave to settle then top in one pass, bead depth permitting. U know nick if he can use 10mm bead he will an I do the same if I can get away with it. We used power float then he followed me with traditional float then then sponge up. Done. CPI is much cheaper than OCR
 

grump

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We didn't. I think CPI say not to if I remember write, I've not spoke with them for ages tho. As long as the background ain't to thirsty then I would. Basically them same as OCR 6.1.1 with chemical
 

nickelarse

Private Member
alright spunk!

right. basically standard cpi general purpose is 2 coat gear. euromix have a one coat that is basically mono and is coloured. thats designed for scraping

iv used a fair bit of general, and one coat once. the one coat is nice gear and sprays well, really fine finish but takes forever to set. in warm wether it was still wet in the afternoon and i had to finish in the morning

with the general purpose, i used to always use it as you would site mix, scratch and then top a few days later. iv used it like an ocr a few times now tho and havent had any problems. the euromix rep for my area said unofficially that it can be used as an ocr in the right circumstances but they wont cover you if it fucks up. i only used it as an ocr on 2 jobs. one in london which was a big curved wall on a round building. it was nov/dec time and it was really cold and on new blockwork. i ended up first thing doing a tightish pass, then giving it a rough flatten off and going straight back over it. it just about floated by 4. came out really nice tho. capital spread helped me out on that one. he'll be able to back me up on that. i also had an elevation there, about 20-30m, and i was getting a bit pushed for time on the job. i sprayed that one evening and left it like you would mono, and in the morn about 7 i sectioned and misted with water and floated and then sponged. it worked but i wouldnt recommend it as an hour later id have been screwed i think. but the i sectioned finish would have looked alright if i was allowed to leave it like that.

on the job i did with grump, we 2 coated as it was on mixed backgrounds. on the new blockwork i used it as an ocr again as it was my last job b4 i left. again on that i just put a tight pass over, quick flatten and a cup of tea then topped it. it was pretty warm and we were floated by 2ish. again looked nice and no probs or callbacks. i reckon you could do it with site mix too tbh on small areas. just a tightish one, let it pull so it wont slump then top it and float. blocks dont show through and its painted anyway. but yeah you do have to fill out your bells a lot
 

goody

Private Member
I know where your coming from there spunk asking all the questions. For such an obvious need there isn't an obvious answer really! I'd use parmurex as a one coat solution(2pass) render. Similar in cost to weber OCR. Comes back to expense though vs traditional.
Incidentally was stuck in traffic earlier and low and behold there was a gang spraying a grey render on a big old stone/lime pointed house next to the road. I asked them what they were spraying and the guy said sand & cement going well! There were 3 of them plus from what I could see a big concrete mixer and diesel machine.
Yes.....great but a bit of a setup manpower & machinery vs traditional. Won't get in to the suitability of the gear on that substrate or no insulation.
Can anybody clarify if parmurex is breathable compared to basic s&c? As in better for the building?
 

spunky

Private Member
Goody is parmurex coloured and when you say to pass do you mean 2 passes same day or different days or spray 20 then pit you're second pass on etc cheers butt
 

PFTwales

Well-Known Member
I know where your coming from there spunk asking all the questions. For such an obvious need there isn't an obvious answer really! I'd use parmurex as a one coat solution(2pass) render. Similar in cost to weber OCR. Comes back to expense though vs traditional.
Incidentally was stuck in traffic earlier and low and behold there was a gang spraying a grey render on a big old stone/lime pointed house next to the road. I asked them what they were spraying and the guy said sand & cement going well! There were 3 of them plus from what I could see a big concrete mixer and diesel machine.
Yes.....great but a bit of a setup manpower & machinery vs traditional. Won't get in to the suitability of the gear on that substrate or no insulation.
Can anybody clarify if parmurex is breathable compared to basic s&c? As in better for the building?

You sure about that price for Parmurex darran. £7.50 a bag is about the best i seen
 

goody

Private Member
Parmurex is their grey OCR. 2 passes wet on wet like mono or if the conditions are right 1 fat pass like mono.
 

Arti

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Slighty off topic about using a machine but is OCR as fickle as S&C regarding cracking?
 

spunky

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Sorry goody im chasing you round the forum, do you think its possible in this weather to spray 2 passes of parmurex at 15mm and still be able to get a float on it?
 

goody

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I don't know really spunky. Got a massive long retaining wall to do in the next week or so. I'd say one or two passes at full thickness sprayed late then I sectioned and floated is a possibility. Might be too hard though. Obviously you'd only open up a lift and float that then move on etc. Once the skins off the clock starts whizzing. I did the very same thing with some damp garden planter wall in mono. Sprayed and I sectioned next day and it floated up perfect. That was just regular mono not the fine gf. So I've more confidence in this again. What are your thoughts?
 

goody

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Couple more things....I'd say you've got to be I-sectioning when it's like monorex on the same day and it's hanging wet but youve got to tease the skin off. Much past that level of setness and you'll have problems I think. Bear in mind it's wasteful to I section off the gear compared to trad. It does leave the wall alone more I suppose as your not over working it, causing sagging etc trying to straighten the thickness when wet so might be better from a laittance/cracking point of view?
 
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owls

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I don't know really spunky. Got a massive long retaining wall to do in the next week or so. I'd say one or two passes at full thickness sprayed late then I sectioned and floated is a possibility. Might be too hard though. Obviously you'd only open up a lift and float that then move on etc. Once the skins off the clock starts whizzing. I did the very same thing with some damp garden planter wall in mono. Sprayed and I sectioned next day and it floated up perfect. That was just regular mono not the fine gf. So I've more confidence in this again. What are your thoughts?

if your putting it on to float up, how come your not using tradirex instead of parmurex? this has a higher lime content in it, and silca sand it gives a lovely finish, when floated.
 

spunky

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I don't know tbh im just used to either ruling it then float and sponge, I've I section up210 and sponged it the next day, i can remember if I didn't scrape every bit and sponged it it showed up alot but I don't know if it left a good enough finish for float finish we were using bucket coat over the top
I don't know if it would be worth on the second pass have a lad ruling it with a serrated edge then say when you're on the next lift another lad comes behind ruling it again with a normal edge then when you've finished all drop back float and sponge but then you're still fighting how much you can get on quick enough to merit you all been there
I'm not sure if we'd be better off spraying CPI as a scratch and maybe just doing the top coat by hand its a toughie say 500m if a 2-1 finished 50m a day with Ocr its 10 days it would take slightly less by hand on the top coat alone but if we scratched it with the machine in a couple of days were ok because were paying 17 quid for a tonne of sand compared to the cost of ocr but I don't know what we can or can't do with the machine anyway, like the idea of I sectioning it though just a bit weary if its as good as float/sponge
 

goody

Private Member
Any spraying and your onto masking. Confusing at the best of times this flat modern render scenario. There's such a gap in the market for exactly the product your after spunky. a smooth mono ffs but at realistic prices. As far as i can see....the mono manufacturers should be developing a product as efficient as mono but with the finish of sand & cement. It's what people want. Forget acrylics over base coats.....far too expensive and like a poxy onion!!
 

goody

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tradirex.....don't hear so much of that one. Same price though yes owls? Will it slump more so needing two separate coats?
 

spunky

Private Member
Any spraying and your onto masking. Confusing at the best of times this flat modern render scenario. There's such a gap in the market for exactly the product your after spunky. a smooth mono ffs but at realistic prices. As far as i can see....the mono manufacturers should be developing a product as efficient as mono but with the finish of sand & cement. It's what people want. Forget acrylics over base coats.....far too expensive and like a poxy onion!!
exactly mate and something to suit thin coats
 

Curry

Private Member
cpi has a new one coat for rubbing up. 2 passes and rub same day ive yet to use it but my dad had a lenghty discussion with Andy cowland from cpi about it. They developed it for some olypic job or something
 
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