Sand and Cement queries.

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LMJ90

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This is my first post on here. I've used this forum extensively for about 3-4 years, invaluable!

However, I'm now in the middle of my own self build, and Im just after some clarification on the ratios for the external rendering. We've had some extension work done, this has been scratched 4-1 + render additive. Top coat was 5-1-1 Sand OPC Lime + Waterproofer, before finishing using a sponge float.

A few of you on here have specified 5-1 scratch and 6-1-1, though isn't this a little soft? (I've been using 6-1 to repair internally, old floated walls). And since I'm sponge floating, is it too weak / soft for this finish outside? Finish will be painted. Rest of house is red brick, and I'm looking to scud it in SBR / OPC 2-1 prior to scratching. Any pointers would be much appreciated, I have done a little search, but would just like some clarity before continuing. Sorry for the long winded post, I think that's everything.
Thanks guys!
 
There's also some inconsistency on which coat you guys put your waterproofer? I put additives in scratch, and waterproofer into the top coat, maybe 10-20ml more in salty / sea air.
 
Thats fine from what you've described everyone likes to vary some wont put a waterproofer in top coat but seems like you've taken good advice from the forum Welcome :RpS_thumbsup:
 
the quality of the sand is important. you do need to employ a competent render. this is not a diy job.
 
Thanks for the welcome! I'm a joiner first, but never turn down a few skimming jobs here and there, find it very rewarding. I'm a self taught plasterer, and picked up some good pointers from some very good spreads on the way! The only thing I do struggle with so far is knowing exactly when to hit the top coat with the sponge. I never have much luck with a sponge float, steer well away from them and usually stick to car washing sponges. I'm keeping water to a minimum as I'm after a fine fimish.
 
Yes, hard to get good sand, I use the same people for rendering sand all the time,avoiding jewsons,selco,wickes.
 
Welcome along,as Jon said concretes and bricks it'll be fine. Blocks of 7N and under the mix will be weaker ie 5:1 / 6:1:1, And then progressively lower for weaker blocks:RpS_thumbup:
 
johniosaif said:
Yes, hard to get good sand, I use the same people for rendering sand all the time,avoiding jewsons,selco,wickes.
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i know my local pits and can purchase top quality sand for rendering it does make a hell of a difference. that is why we do not let people who nothing about the job order the material
 
House is post war ('49) and is Caernarfon red brick, which was used extensively along the North West coast of Wales, Shrewsbury, Liverpool and beyond I believe... I'm not a diyer, I take my work very seriously, Im just overly cautious when delving into things that I don't do everyday. I am confident that ill do a good job, and just after some good, sound advice. :-)
 
malc said:
i know my local pits and can purchase top quality sand for rendering it does make a hell of a difference. that is why we do not let people who nothing about the job order the material
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I remember when my father could get a trailer full for a fiver, not a 25 kg bag, my home place is called 'home of the rocks 'due to the pits,ballycarnan in English, big difference in the sand here and ireland,
 
God ive had some nightmares with shite sand over the years even from the suppliers you have had good sand off in the past must admit since moving down south i have found the quality better than up north. Weird!!!
 
after a lot of bad experiences we stick to fine silver sand and lime. Cracking finish and its the same every time, I think this is a Devonshire thing though (or possibly Cornish)
 
Olican said:
after a lot of bad experiences we stick to fine silver sand and lime. Cracking finish and its the same every time, I think this is a Devonshire thing though (or possibly Cornish)
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Yeah thats i got recommended to use so its good then! Will have to give it a wirl on next job what supplier you use im not to far from you?
 
smoother09 said:
Yeah thats i got recommended to use so its good then! Will have to give it a wirl on next job what supplier you use im not to far from you?
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usually interline or Jewson. They all stock it. Used to get the lime from B&Q but they stopped selling it, maybe Newton Armpit branch stock it
 
Olican said:
usually interline or Jewson. They all stock it. Used to get the lime from B&Q but they stopped selling it, maybe Newton Armpit branch stock it
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I'll do a bit of googling!! Newton armpit! This is were all the best plasterers live so they reckon :RpS_crying: i better move:RpS_lol:
 
smoother09 said:
I'll do a bit of googling!! Newton armpit! This is were all the best plasterers live so they reckon :RpS_crying: i better move:RpS_lol:
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Newton Armpit was voted the UKs ugliest market town 5 years running, think its tidied itself up a bit now :RpS_thumbsup: I like the town, full of weirdos
 
smoother09 said:
God ive had some nightmares with shite sand over the years even from the suppliers you have had good sand off in the past must admit since moving down south i have found the quality better than up north. Weird!!!
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That goes with most things ,in fact thinking about it ,everything:RpS_biggrin:
 
Thanks! And thank you for the welcome. I am a joiner first, but I have been plastering for 6-7 years. I am self taught, though I have picked up a lot of pointers from good, competent spreads who've been doing it longer than I've been alive! I don't deem myself a diyer, I take it very seriously, I guess I'm just that bit more cautious about things that I don't do daily... and where better to come for some sound advice! (My replies don't seem to be appearing? So apologies if I've repeated myself?)
 
if you cant render and rule it flat , dont bother getting a float on it , this is the skill off the trade , you cant learn to render by reading this one , 5-1 , 6-1 it dont matter .
 
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LMJ90 said:
Thanks for the welcome! I'm a joiner first, but never turn down a few skimming jobs here and there, find it very rewarding. I'm a self taught plasterer, and picked up some good pointers from some very good spreads on the way! The only thing I do struggle with so far is knowing exactly when to hit the top coat with the sponge. I never have much luck with a sponge float, steer well away from them and usually stick to car washing sponges. I'm keeping water to a minimum as I'm after a fine fimish.
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First of all mate , are you floating it up first ? So putting the gear on darby it etc ... Let it pick up float it then a sponge ?
 
CTPlastering said:
First of all mate , are you floating it up first ? So putting the gear on darby it etc ... Let it pick up float it then a sponge ?
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Aye that's what I'm doing, laying it on, darby, let it pick up, poly floating it then finished with a sponge. I just can't seem to get the hang of sponge floats, anyone else struggle? I always have to revert to the car washing sponges, and it kills my hands! Marigolds time?
 
LMJ90 said:
Aye that's what I'm doing, laying it on, darby, let it pick up, poly floating it then finished with a sponge. I just can't seem to get the hang of sponge floats, anyone else struggle? I always have to revert to the car washing sponges, and it kills my hands! Marigolds time?
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I use one all the time with no issue's.
That question is a bit like me asking on a carpenters forum how to cut a mitre for skirting
!!!
 
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