Sand & cement render

[Metropolitan Plastering]

Right, I know there are loads of posts about render and cracks but this job is doing my nut in!!
We hacked off an old dash as it was blown and had no scratch we literally peeled it off no hassle..
We scratched over the thermalites with a 4:1 mix with plenty of water proofer. Left it a couple of weeks then started top coating using 5:1:1 with waterproofer/retarder .
Today we even unibonded over the scratch before top coating it all went well ruled off rubbed up sweet but then cracks appear everywhere, I don't have an answer for the customer it's so frustrating , can anyone help ???

 

[Builderboi]

Uni bond in outside?

 

[johniosaif]

Nearly everything you did was wrong,
give the customer a plasterers number,
i hope you're on the wind up..

 

[jesssop]

and too much waterproofer

 

[Metropolitan Plastering]

Just to try and hold it back,

 

[Metropolitan Plastering]

Nearly everything you did was wrong,
give the customer a plasterers number,
i hope you're on the wind up..

What is so wrong in what we've done I've been plastering for 10 yrs never had a problem rendering this way !!

 

[Metropolitan Plastering]

Uni bond in outside?

Just to try and hold it back!

 

[Metropolitan Plastering]

and too much waterproofer

Do you think? We have a big water butt and use one w/p and retarder in a full butt

 

[jdplast]

your main problem was that after a couple of weeks the scratch coat was dry as fook and sucking like a .....well fill in the blank yourself.

The pva wont do much you needed to wet the scratch coat down and possibly could have done with curing it during drying

 

[Metropolitan Plastering]

your main problem was that after a couple of weeks the scratch coat was dry as fook and sucking like a .....well fill in the blank yourself.

The pva wont do much you needed to wet the scratch coat down and possibly could have done with curing it during drying

Yea we did a flank on the side upto an expansion joint and wet the scratch down without pva and sucked in really quick, so thought I'd try pva it did hold back more without a doubt today with the pva !
What do you mean by curing it ?

 

[TheWand]

What is so wrong in what we've done I've been plastering for 10 yrs never had a problem rendering this way !!

:RpS_laugh:................you should know whats wrong if you've been spreading for 10 years....................get a proper plasterer to do it next time

 

[TheWand]

Yea we did a flank on the side upto an expansion joint and wet the scratch down without pva and sucked in really quick, so thought I'd try pva it did hold back more without a doubt today with the pva !
What do you mean by curing it ?

:RpS_lol:

 

[Metropolitan Plastering]

:RpS_lol:

The wand, you are one helpfully prick!
Here's me thinking this site was for people to help each other out, then I come across a ****** like you ! I must have been wrong .
You must be the b*ll***s I wish I was as good as you !

 

[johniosaif]

Scratch should be 6/1 on thermalites in my opinion,
keep damp for a week
then float over with 6/1/1

 

[TheWand]

The wand, you are one helpfully prick!
Here's me thinking this site was for people to help each other out, then I come across a ****** like you ! I must have been wrong .
You must be the b*ll***s I wish I was as good as you !

you dont have to be as good as me. just dont take on jobs you cant do and the customer wont be annoyed and your reputation wont be in pieces after the customer tells all there friends you dont know what your doing

 

[Metropolitan Plastering]

Scratch should be 6/1 on thermalites in my opinion,
keep damp for a week
then float over with 6/1/1

Something to think about, I was taught 4:1 and was told top coat should be weaker than scratch !

 

[wiganlad]

your main problem was that after a couple of weeks the scratch coat was dry as fook and sucking like a .....well fill in the blank yourself.

The pva wont do much you needed to wet the scratch coat down and possibly could have done with curing it during drying

@jdplast where in wigan you from

 

[plastererpeter]

Y use waterproofer in scratch coat mate

 

[Metropolitan Plastering]

you dont have to be as good as me. just dont take on jobs you cant do and the customer wont be annoyed and your reputation wont be in pieces after the customer tells all there friends you dont know what your doing

Cos I must be the only spread out there that have ever come across problems, it must be because I don't know what I'm doing! I'm interested to know how the best would have done it !

 

[Metropolitan Plastering]

Y use waterproofer in scratch coat mate

Always have mate was taught that way stops the top coat sucking in .

 

[User___removed]

Scratch should be 6/1 on thermalites in my opinion,
keep damp for a week
then float over with 6/1/1

To be fair join I would go stronger than that.
I would damp down blocks,scratch with 5/1/1,with a drop of sbr and bed mesh in.finish with 6/1/1

 

[TheWand]

Cos I must be the only spread out there that have ever come across problems, it must be because I don't know what I'm doing! I'm interested to know how the best would have done it !

your man johniosaif as already mentioned to keep it weak on thermolites and his top coat is weaker than his scratch with added lime. still dont know why you wanna use PVA

 

[plastererpeter]

P a def a no no mate. I seen peeps put bit soft sand in mix then they wonder y it blows

 

[johniosaif]

To be fair join I would go stronger than that.
I would damp down blocks,scratch with 5/1/1,with a drop of sbr and bed mesh in.finish with 6/1/1

I'd live with this happily enough ,six and one is more correct for thermalites,I would've of scudded


with a slurry with sbr but Irish style ,splatter coat type,

 

[plastererpeter]

Pva

 

[jesssop]

id do 5-1 6-1-1

 

[johniosaif]

Cos I must be the only spread out there that have ever come across problems, it must be because I don't know what I'm doing! I'm interested to know how the best would have done it !

Everyone has had
problems,they rest are liars

 

[Metropolitan Plastering]

your man johniosaif as already mentioned to keep it weak on thermolites and his top coat is weaker than his scratch with added lime. still dont know why you wanna use PVA

I used pva to try and hold it back a bit as the side sucked in pretty quick, thought it would be worth a try.

 

[plastererpeter]

Think u been unlucky May be it the hot weather drying out finish coat far to quick

 

[johniosaif]

Waterproofer in the scratch is fine, don't over do it, follow guidelines,

 

[Marshy]

I'd have SBR slurried the thermalites before attempting any scratch coat !?

 

[Metropolitan Plastering]

Think u been unlucky May be it the hot weather drying out finish coat far to quick

I was thinking the weather, I pulled of job for a bit to wait gorgeous an overcast day but customer was kicking off a bit !!!

 

[Fatarm]

I'd live with this happily enough ,six and one is more correct for thermalites,I would've of scudded


with a slurry with sbr but Irish style ,splatter coat type,

scud it ..asif....:RpS_unsure:

is that the correct terminology..:RpS_wink:

 

[Metropolitan Plastering]

I'd have SBR slurried the thermalites before attempting any scratch coat !?

I'm never too old to learn!!!
I've done the sbr slurry over a painted surface but never over thermalites . Always done the same as what I have on this job on thermalites in the past !!

 

[Arti]

Just remember to keep it weak on thermalites. give them a good soak before you fire ya scratch on and keep ya PVA for internal's