Render going off to fast??

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Mrkpc28

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hi there everyone new to this site so go easy on me! Just a little bit of advice needed? i have been rendering the outside of a extension and have scratch coated the whole of the extension and i have now started doing the top coats and its been going off on me b4 i can finish lying on! the scratch coat has been on there about a week ish? just wondering what i could do to stop it going off so fast have soaked the walls but then it just saggs! should i try pva on the scratch b4 i top coat?
any advice would be helpful
thanks!
 
not sure what sbr is sorry? the mix for the scratch was four sand one cement and one lime and then a dash of 3 in 1 admix!
 
should have used more admix mate... when you say 3 in one ill take it you mean waterproofer / plasticiser / salt neutraliser...

a dash usually aint enough, depends which one you used but you should read the tub mate...

bout 3/4 of a mcdonalds coffee cup per mix is what i use...
 
thanks for the advice i only put a dash in so i will put in more the nxt time! any advice on how to slow the top coat now then?
 
long as youve scratched it really well - sbr/water mix...

sbr - styrene butadeine rubber, available from all good builders merchants, like waterproof pva... use with cement based stuff..

5 litre tub about 15-20 quid...

as henry says, you could have added sbr to the scratch as a waterproofer...
 
Cool so if i got some of that sbr and put it in the scratch coat nxt time the top coat shouldnt go off as fast?? would pva ing the scratch coat slow to top coat down?
 
dont use pva
if you use the 3 in 1 admix at the correct dose you wont have any probs next time...
use sbr mixed with water to slow the top coat down now the scratch is on...

pva isnt waterproof, when it gets damp or wet it'll liven back up again, sbr wont..
 
Dont use PVA mate its just the wrong stuff for what you want without going into detail, give your scratch coat a good soaking with the hose and then leave it a good half hour or so then wack it on.
 
ok thanks guys am top coating tomorrow so hopefully all will go well but from now on will be using sbr in all scratch coats and plenty of it!!
 
wait till the winter comes, youll be back on going 'why am i still sitting here waiting to float up at 2 o'clock in the morning?' :RpS_laugh:
 
I dont ever use sbr in my scratch as i have found it sends it off quicker or you get patchy results, best waterproofer i have found would be cementone as mentioned. As for wetting it down when you give it a good soaking let it dry out a bit before you lay it on then you wont get sagging, Another option is to not over mix your render its not the best to lay on but it stays wetter for longer and it rubs up nice.
 
ive never used sbr in scratchcoat either , just a decent waterproofer , the more you do the more you will get to know what ratio to use , some times you need the top coat to go off quicker , cold weather , small area etc so you can dilute the additive , sometimes you need time , so use as directed . i use 2 different waterproofers depending on what im doing , but in your case i would just dampen down wall , not soak so all the water saturates the bottom , just a spray over the area and float as normal . Its all about experience
 
If you've over-wet a wall and don't wanna wait for it to take up, run a tight coat along the scratch - this will push the water out, then you can lay on as normal :RpS_thumbup:
 
how many on here put lime in their scratch coat(3 to 1,all the way), that in itself will make if suck like a prostitute on coke
 
Use a retarder[slowing]such as rendamix or waterproofer depending time of year temp etc.Takes lots of trial and errors when you have not done much like myself.
 
totallyplastered said:
Use a retarder[slowing]such as rendamix or waterproofer depending time of year temp etc.Takes lots of trial and errors when you have not done much like myself.
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So lets get this right, you've done **** all rendering but you'll still drag up a six month old thread to treat us to your wisdom.
Get a ******* grip quickly or you are going to be treated as a joke on here, and I'm not being mean I'm trying to help you.
 
Hi, I plan to use a home made Tyrolean mix with a flicker gun to cover a block wall, with an idea to add colouring. Can anyone advise me about the type of sand I should use and type of colouring I could use? Do I need to water proof this also? Can I use latex/unibond to help it stick? How much? I can not use a ready mix because It is not available in the country I plan to use it and I would not pay the prices they ask anyway. Any tips would be most helpful as I have a lot of wall to cover. Many thanks, Lawrence. P.s Using it in a very hot country!
 
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