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Harry12

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Hi guys , I'm new here and thought I'd introduce myself by getting your thoughts/advice about a job I'm on at the moment .
it's a old end terrace house built with stone , we've hacked off existing render on gable .
Plan is to re render in s+c ( client refuses to pay for lime plaster).

so first we are going to sbr slurry.
Thinking about a 2:1 scud coat
then 4:1 scratch with w/p
Then 5:1:1 top.
That's our usual method apart from the fact we wouldn't normally start one off these this time off year .
would anyone do it differently?
slightly weaker mixes etc?
 
hi harry , welcome ,, unfortunately always seem to get outside work this time of year,,,every one could tell you different mixes to use so if your happy with what u use i would stick with it,, at least you"ve only got yourself to blame if things go wrong,,,
 
hi harry i woukd stick to ur methods as it sounds about right to me. maybe just reduce the waterproofer/retarder or not wet down scratch to much or at all. will be fine.

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Seems ok to me but I would not bother with the scud coat. Think that is an Irish thing? Your problem will be getting the top coat to set before dark. How about 2 scratch coats first usual thickness and the second a tight one with no waterproofer. You will get a bit of grab there if it is dry enough rather than the dreaded slump and ripples.
 
problem with a thin 2nd scratch coat, ie... you dont want a thicker coat on top of a thinner coat...
 
Cheers for the replies I like the sound off the second coat without waterproofer, might give that a go.
also have any off you guys tried the speed skim on render? My young lad keeps banging on about it.... Looks a bit flimsy to me for ruling off.
 
I would do five to one first coat, leave it nice and flat for second and scratched, leave for a week and then 6/1 /1
i also do like the scud coat, maybe because I am irish,
embedded mesh or fibres in first coat would help too in my opinion .
 
Cheers for the replies I like the sound off the second coat without waterproofer, might give that a go.
also have any off you guys tried the speed skim on render? My young lad keeps banging on about it.... Looks a bit flimsy to me for ruling off.
It's too flimsy for ruling of render imo. Ideal for flattening first coat of plaster.
 
Agreed about weaker but what you about the coats should be thinner is rubbish.5mm scratch 10mm top.



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Going thinner with coats as you go out is basics mate, good luck tho..

5mm scratch coat ?? you would scratch straight through to the brickwork mate... might as well save the money you would spend on waterproofer cus it would be a waste of time..lol
 
Your talking ballbag son.


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think its you talking bollox mate.. you dont know or understand basics... can you explain exactly how you can go thicker with your coats ?? ie.. 5mm scratch coat ( WTF ) then a 10mm top coat... now that is bollox... we learned this 1st week in college ...
 
Seems ok to me but I would not bother with the scud coat. Think that is an Irish thing? Your problem will be getting the top coat to set before dark. How about 2 scratch coats first usual thickness and the second a tight one with no waterproofer. You will get a bit of grab there if it is dry enough rather than the dreaded slump and ripples.

Here your go pal.2 scratchcoats,the second being a tight 1.so would you put second pass of mono on thinner than the first?


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Well.. your supposed to let each coat dry out ( sand and cement the guys using right ? ) with OCR, mono, yes the 2 coats become 1... but he;s using sand/cement, and you dont go over a 5mm coat with a 10mm coat 9 as you posted ) each to their own tho pal..x
 
Specification
It is normal practice to apply render in two coats. The first coat (undercoat) should be trowelled on to a thickness of 10mm to 16mm and scratched. An adequate period of time should elapse between the application of coats in order to allow the undercoat to dry out thoroughly, but not too quickly, before the next coat is applied.

The thickness of the final coat will be governed to some extent by the texture required, but will normally be 6mm to 10mm, as finished. The final coat should be thinner and no stronger than the undercoat and this, in turn, no stronger than the substrate. The finishes suitable for external renderings
 
there ya go, took 2 mins to fing spec for rendering on Google... the max you can go is the same strength and same thickness, tho usually you go weaker and thinner..
 
Ok so if the topcoat is 10mm as stated,you would apply your scratch thicker than that with a over all thickness of around 22mm?


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The 10mm top coat would be a max, id have an overall of about 18mm or thereabouts 18-20 mm finished thickness ( 12mm scratch/8mm top )
 
I personally have never had any trouble when scratch coat has been thinner than top coat :rolleyes)

But its wrong... why would you do it back to front anyway ??.. no point, would suck in like fuk aswell without a decent scratch coat...
 
dont think i have ever put top coat on thicker than scratch coat,,, always do all thew work in scratch coat so top coat is a nice even coat all over
 
Oh so you went to college then.week course?


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4 years actuallyt chancer.. advanced city and guilds... block release during my apprentiship... you should have tried it, that way you;d know about the the thicknesses of sand/cement render...
 
4 years actuallyt chancer.. advanced city and guilds... block release during my apprentiship... you should have tried it, that way you;d know about the the thicknesses of sand/cement render...

Julian Oates by any chance? Shirecliffe?
 
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I think the only time you might get problems with the scratch coat thinner is when there is little key on the substrate.

I like the top to be of decent thickness coz its easier to rub up IMO.
 
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