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Hello all! I haven't got that much experience rendering large areas, that's not to say that what i have done's turned out alright with a sponge float! Anyway, ive got the whole exterior of a newbuild to do. front and back's no problem but i'm worried the two side walls are too big for me to do in one hit - although the scratch shouldn't be a problem. My question is whats the best way to divide a wall and do two hits without leaving a join??? :p
 
If the size of the area you are talking about does not require expansion joints id say get somone to give you a hand by that i maen another plasterer or labourer or both
 
Hello all! I haven't got that much experience rendering large areas, that's not to say that what i have done's turned out alright with a sponge float! Anyway, ive got the whole exterior of a newbuild to do. front and back's no problem but i'm worried the two side walls are too big for me to do in one hit - although the scratch shouldn't be a problem. My question is whats the best way to divide a wall and do two hits without leaving a join??? :p  
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do it in sections top first then bottom
 
u wanna use stainless steel beads when rendering cause if u use galvanised they will go bare when u rub the render they will eventually rust and crack the render

also make your scratch coat stronger than the top coat this is for when u get movement they will move at diff rates and the whole thing wont crack in one :cool:
 
you could always use the old trick that plasterers who cant really render use, put waterproofer in the scratch,you will have all the time in the world,but get the agent/archies say so first!
 
no mate waterproofer should only be used as an answer to a problem,ie,water ingress,if theres no problem you might create one by making a water barrier,most builds have a cavity ,yes,thats what stops damp,most new and old renders are vapour permiable as in water can travel in but most importantly can get out,trap water anywere and it will freeze ,expand and crack .
 
always waterproof the scratch. most of the time in top coat also ( would on this occasion as it gives you that little bit of time). think you might need a few extra hands if you want to bring it down in one day. render is a balls to match but can be done . the cold will help slow things down. good luck. its your decision but the job always looks better done in one day. just have to throw some labour at it. where you at? maybe a couple of us could help you out!
 
gmw. your making sense there. kind of. but water would have to come from the inside though. always thought i was waterproofing the building.
 
always waterproof the scratch. most of the time in top coat also ( would on this occasion as it gives you that little bit of time). think you might need a few extra hands if you want to bring it down in one day.  render is a balls to match but can be done . the cold will help slow things down. good luck. its your decision but the job always looks better done in one day. just have to throw some labour at it. where you at? maybe a couple of us could help you out!
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not tryin to start a pi$$ fight but if your gonna waterproof the scratch id deffo waterproof the top as well an make sure theres a good mechanical key between coats,beter still top before the scratch has lost its green!
 
nay g mate. your spot on about the cavity. i usally top coat the following day having givin it a good scratch. isee what your saying about letting the render breath but im always more concerned about damp. thought that was the original reason for render???? im refering to older buildings. i live in london so thats what i mostly do. saying that i have always done the same for cavity walls. just thought if no water could pentrate in then nothing would blow ie freeze and expand.
 
thinkin is as i understand it that a large renderd can expell more amounts of water than it soaks up during a year so even taking moisture out of the cavity,as you all no most render damage is coarsed by water geting behind it,geting trapped an blowinga s in badly fitting windows an sills or on corners an beads,thats the way i see it any way.but im always open to a bit of education!
 
no mate waterproofer should only be used as an answer to a problem,ie,water ingress,if theres no problem you might create one by making a water barrier,most builds have a cavity ,yes,thats what stops damp,most new and old renders are vapour permiable as in water can travel in but most importantly can get out,trap water anywere and it will freeze ,expand and crack .
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yes....... i understand now, that does make sence. cheers
 
but im still confused....... is it best not to bother with waterproofer with a re-render
and ok to use on new build.
 
so waterproofer in the top coat shouldnt hurt it will just repel the water?
how do you lads do it i always add it to the scratch coat
 
unless its specified in the spec i never use it, if you put it in the scratch coat the only place for the water in the top coat go is down the wall. you end up having to rub it up in stripes going across the wall as the water runs out of it instead of soaking in evenly all over, sorry if a bit vague, early start today!
 
would defo put it in the scratch because you have a large area. and me personally, because of the size, the top coat also. :-X
 
ok what about if you have to use a sbr slurry on red brick..... what do you use then. cheers
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thats a good point because it acts as a waterproofer
 
if youve got to use a waterproofer for whater id use it right the way thrugh scratch top dub all if you put only in the first coat sand not in the top,then somebody goes and gives it the old tompo water sheild or some such silly bollo$$s then youve got a water trap then yor renders gonna be as hollow as a plumbers promise :eek:
 
so what your saying is....... if u use waterproofer use it in scratch and top coat so you do get a water trap. or dont use it at all

whats that poll all about?
 
so what your saying is....... if u use waterproofer use it in scratch and top coat so you do get a water trap. or dont use it at all

whats that poll all about?
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bang on mate,if your asked to use any sort of water vapour barrier/water reppellant carry the waterproofer right the way thru the work,what they do later or any damp probs your coverd you did what was asked,adding when not asked for is courting danger,if only most spreads would admit they use it cause it makes a hard job piss easy,i,used it for years till it bit me on the arse!
 
what it is..... ive only ever done a little bit of rendering ganden walls ect, nothing with a beads. so im a bit parainod that if a render a wall with beads either end,. by the time i get to the other end of the wall the render is not the right thickness. so i was thinking if i used more screeds, there will be less chance of this happening.
 
i know what you mean mate, ive only done a few rendering jobs. on one at the min with colums that ive beaded so i can work off of these as only narrow.

You are supposed to stick a screed at either end of the wall and then make them slightly narrower than your featheredge so you can rule off them (hope that makes sense).

Im just shite ruling, But i have found that i run it over and take off the high spots then fill the lows and when you float up it makes it all the same level anyway. Im sure someone more experienced will be along

And.......(to the pros) with regards to screeds on your float coat do you wait for them to firm up slightly prior to filling? I presume not as it would not float up at the same time. My trouble is i destroy the screed while trying to rule off it!!!! Any Advice??
 
what it is..... ive only ever done a little bit of rendering ganden walls ect, nothing with a beads. so im a bit parainod that if a render a wall with beads either end,. by the time i get to the other end of the wall the render is not the right thickness. so i was thinking if i used more screeds, there will be less chance of this happening.
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ill give you my view ,but ive had a sherry or two so if i wonder off please forgive,also just my way ,not the law ,take or leave it.
outside render is not plastering,people dont fit kitchens up the gable i just did so i can be a bit lax with the edge,thats not to say rough,but inside lads need to chill and realise
it hasnt got to really be straight but its got to look like it is,screeds are good for getting depth and plumb with your scratch but a top coat should go off all in one as applied left to right,top to bottom trying to always into work a wet edge edge,easyier said than done ,if you cant or you think you cant ,get a lift or chop it up with beads an expansions,30 - 40 metres of fined render is enough for me on unbroken work you must work to your own limits.
i like to do all the hard work in the scratch,as level and plumb as its gonna get then a nice even topcoat @required depth,then prey to the gods,top a few chickens an you may get away with it.
 
you dont have to rule it off lads , as long as you lay it on nice and neat like skimming it will be fine
 
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