Rendering. PLEASE HELP

[bobski]

View attachment 78140spoke to soon
This wall took all day to go off so surely can't be drying too quick..
I'm stumped

It's straightforward mate!



Your mix ratios!




100%


Thank me later.

 

[G2607]

1st coat
8 Plastering sand
Half bag cement
500ml waterproofer

Top coat
9 plastering sand
Half bag cement
2 shovels hydrated lime

Where am I going wrong?

 

[bobski]

1st coat
8 Plastering sand
Half bag cement
500ml waterproofer

Top coat
9 plastering sand
Half bag cement
2 shovels hydrated lime

Where am I going wrong?

Ok

Back to basics first


Sand is the aggregate (won't stick to itself or anything else - without........)

Binders


Cement and lime are binders (bind s**t together and stick)


You have more in the 2nd than 1st coat, hence it's stronger (and heavier) which leads to.......


Your predicament.......


To much 'weight' (and strength) over a more feeble base.


You can adjust, and it'll be fine.






.

 

[G2607]

Makes a lot of sense. Thank you, really appreciate it

 

[bobski]

Makes a lot of sense. Thank you, really appreciate it

Stay with 1st coat (I'd add fibres myself though)


2nd - go 8 to ¼ to 1 (and fibres again (small ones))

 

[Salfordspread]

Stay with 1st coat (I'd add fibres myself though)


2nd - go 8 to ¼ to 1 (and fibres again (small ones))

Ŵe used to add fbres in the scratch coat many moons ago before good old ocr came along . That's a proper old school trick that is that only a few of us old dinasors use .

 

[Salfordspread]

These we used to get when the dreaded bell mixer raised its ugly head

 

[bobski]

These we used to get when the dreaded bell mixer raised its ugly head View attachment 78145

That's them, although we changed to 6mm


Found 20's could sometimes pop up "out" on warm days rubbing up.


I carry 2mm , 6mm and 8mm fibres now.


Don't even see them.


Work well though, knit it tight.

 

[essexandy]

That's them, although we changed to 6mm


Found 20's could sometimes pop up "out" on warm days rubbing up.


I carry 2mm , 6mm and 8mm fibres now.


Don't even see them.


Work well though, knit it tight.

I reckon the original Fibremesh (?) brand used to be 40mm long. Finer than a human hair and never had any problems with them. In fact they were way better than the modern clumpy crap that's available now.

 

[bobski]

I reckon the original pubes (?) brand used to be 40mm long. Finer than most hair and never had any problems with them. In fact they were way better than the modern clumpy crap that i have now.

Ah, those were the days.

 

[Salfordspread]

I reckon the original Fibremesh (?) brand used to be 40mm long. Finer than a human hair and never had any problems with them. In fact they were way better than the modern clumpy crap that's available now.

Fibre mesh that's the stuff been a long time since we used them tbh

 

[essexandy]

Fibre mesh that's the stuff been a long time since we used them tbh

I used to buy it from a local ready mixed concrete company up to about 2004. Definitely the best one that has ever been available. A quick stir into your mixing water and the fibres completely separated, never a single clump of them. I used them for both screeding and rendering.

 

[Salfordspread]

I used to buy it from a local ready mixed concrete company up to about 2004. Definitely the best one that has ever been available. A quick stir into your mixing water and the fibres completely separated, never a single clump of them. I used them for both screeding and rendering.

Showing are age now . Ha ha

 

[bobski]

I used to buy it from a local ready mixed concrete company up to about 2004. Definitely the best one that has ever been available. A quick stir into your mixing water and the fibres completely separated, never a single clump of them. I used them for both screeding and rendering.

I think that's the difference between fibreglass and polypropylene fibres.


We used to get proper fibreglass that would separate equally/evenly through the water first, you stick polypropylene ones in there and it looks like frogspawn




Probably cheap Chinese shite flooding the place again?

 

[essexandy]

I think that's the difference between fibreglass and polypropylene fibres.


We used to get proper fibreglass that would separate equally/evenly through the water first, you stick polypropylene ones in there and it looks like frogspawn




Probably cheap Chinese shite flooding the place again?

Possibly, but I thought the original ones were polymer fibres not fibreglass?

 

[bobski]

I think so, we still called them fibreglass though. (Still do)





Did you call them polymer fibres?

Be honest now???

 

[essexandy]

I think so, we still called them fibreglass though. (Still do)





Did you call them polymer fibres?

Be honest now???

Yes mate I did and do, mainly because that's what the manufacturers called them.

 

[bobski]

Yes mate I did and do, mainly because that's what the manufacturers called them.

You still using/getting them?

 

[essexandy]

You still using/getting them?

Not the good ones, haven't been able to find them in years.
Still use the crappy ones in both screed and rendering.

 

[algeeman]

concrete is so much more solid than screed and render

that cracks and never has fibres
it's set it steel

what makes sand and cement and fibres stronger

out of curiosity

 

[Monkey Boy]

concrete is so much more solid than screed and render

that cracks and never has fibres
it's set it steel

what makes sand and cement and fibres stronger

out of curiosity

Go to bed

 

[essexandy]

concrete is so much more solid than screed and render

that cracks and never has fibres
it's set it steel

what makes sand and cement and fibres stronger

out of curiosity

The fibres I first bought were made for the concrete industry you thick c**t. They work in two ways. Millions of fibres criss crossing in the mix give added strength (hence why fibres are spec'ed for screening in place of steel mesh for most applications) and if cracks do form they follow the paths of the individual fibres, meaning that the cracks are ultra fine and usually invisible to the naked eye.

 

[Salfordspread]

The fibres I first bought were made for the concrete industry you thick c**t. They work in two ways. Millions of fibres criss crossing in the mix give added strength (hence why fibres are spec'ed for screening in place of steel mesh for most applications) and if cracks do form they follow the paths of the individual fibres, meaning that the cracks are ultra fine and usually invisible to the naked eye.

Same applies to the hairs in lime . Ha ha there's some M T HEADS on this here forum alright

 

[algeeman]

The fibres I first bought were made for the concrete industry you thick c**t. They work in two ways. Millions of fibres criss crossing in the mix give added strength (hence why fibres are spec'ed for screening in place of steel mesh for most applications) and if cracks do form they follow the paths of the individual fibres, meaning that the cracks are ultra fine and usually invisible to the naked eye.

so why does the render and screed still crack

 

[algeeman]

Same applies to the hairs in lime . Ha ha there's some M T HEADS on this here forum alright

but lime still cracks aswell

 

[Monkey Boy]

I think the large aggregate in concrete acts like type 1 MOT subbase and all the stones play off each other giving great resistance

 

[Cockney]

I think the large aggregate in concrete acts like type 1 MOT subbase and all the stones play off each other giving great resistance

Go to bed!

 

[essexandy]

so why does the render and screed still crack

Same reason screed still cracks with steel mesh embedded mate. Outside forces. Rendering will be for a multitude of different reasons. All you can do is take as many precautions as possible.
You'll know as well as I do that on site the same plot types will have cracks in the same place, that's got to be down to design, hasn't it?

 

[Salfordspread]

but lime still cracks aswell

Yes till the top coat goes on that's why it's sprayed down as much as possible . No material contained water is guaranteed not to crack

 

[malc]

The main reason screed cracks is the D49 is at the base of the screed and not in the middle .

 

[algeeman]

Same reason screed still cracks with steel mesh embedded mate. Outside forces. Rendering will be for a multitude of different reasons. All you can do is take as many precautions as possible.
You'll know as well as I do that on site the same plot types will have cracks in the same place, that's got to be down to design, hasn't it?

fuuck off andy
your the reason why fish fingers have gone up to
£7.75 a box

gonna send Fin to you for a while
il have him back when he's fit to earn

@Danny my little faces things have ceased to exist

 

[Danny]

fuuck off andy
your the reason why fish fingers have gone up to
£7.75 a box

gonna send Fin to you for a while
il have him back when he's fit to earn

@Danny my little faces things have ceased to exist

You have to press the 3 dots

 

[algeeman]

You have to press the 3 dots

mate I'm 6 german beers in
get a train up and show me xx

 

[algeeman]

still not working

at the same time lol

 

[essexandy]

fuuck off andy
your the reason why fish fingers have gone up to
£7.75 a box

gonna send Fin to you for a while
il have him back when he's fit to earn

@Danny my little faces things have ceased to exist

My house is to calm mate, his little head would implode.
You don't have any of these
how odd, ya c**t.