Cracks in render ?

Spray

Well-Known Member
Cracks are mainly a substrate issue ?
Can cracks be stopped by mesh ?
What’s your views
 

Spray

Well-Known Member
Either way book will always stop with applicator!

Ive almost come to the concluion that every job shoul be enough profit to allie to be able to be done again if needed!
Sounds like your pissed off mate with the rendering game
 

essexandy

The Lake Governor
Cracks are mainly a substrate issue ?
Can cracks be stopped by mesh ?
What’s your views
I worked on the same basic eight designs of house for fifteen years. Now unusually in this day and age the builder didn't rush things along and the blockwork had often bee stood for twelve months or more before I rendered/plastered them. It didn't take too long to get to know exactly where cracks would appear on certain house types. Initially I would paper and EML over the cracks and later on started to use fibreglass mesh embedded in the scratchcoat. The cracks never came back through using paper/EML but did on a couple using the fibreglass mesh. Obviously I dropped the fibreglass mesh and carried on using paper/EML.
 

beader

Private Member
Thanks, what I mean is why all of a sudden does everyone put a £90 roll of mesh over a whole house now compared to back in the day
It depends on what you call back in the day?.When I started in 86 it was not available to my knowledge but others may know different.
 

Stevieo

Royal Spin Doctor
Cracks are mainly a substrate issue ?
Can cracks be stopped by mesh ?
What’s your views

0011 hrs on a Sunday morning and Lox is up worrying about cracks in render. You need a week at the seaside, my lad. Maybe even a month.
 

malc

TPF Special Forces
Thanks, what I mean is why all of a sudden does everyone put a £90 roll of mesh over a whole house now compared to back in the day

an area to be rendered would be built with keyed bricks,laid on a bed of lime mortar, as these are now to expensive , it is all block work, built with a strong mix of sand and cement.
 

essexandy

The Lake Governor
an area to be rendered would be built with keyed bricks,laid on a bed of lime mortar, as these are now to expensive , it is all block work, built with a strong mix of sand and cement.
We rendered a couple of sites on fluted flettons and there never seemed to be any cracking, and they were laid with S&C.
 

malc

TPF Special Forces
We rendered a couple of sites on fluted flettons and there never seemed to be any cracking, and they were laid with S&C.

when we was NHBC registered ,we often received advice to use keyed flattens and add lime to the mortar to receive render.
we have stripped new properties of their render and redone for the NHBC. these were often on lightweight blocks.
 

essexandy

The Lake Governor
when we was NHBC registered ,we often received advice to use keyed flattens and add lime to the mortar to receive render.
we have stripped new properties of their render and redone for the NHBC. these were often on lightweight blocks.
Well you know as well as I that people struggle to work with lightweight blocks Malc. And that's brickies as much as spreads. Muck is usually way to strong.
 

vfr12

MOTORC*NT
Well you know as well as I that people struggle to work with lightweight blocks Malc. And that's brickies as much as spreads. Muck is usually way to strong.
Only in uk they are laid on with s&c and the strength of the mortar has nothing to do with this, it’s the suction they can’t overcome. Any other country in the world uses special adhesive, apart from Africa maybe .
 

The Hobo

Well-Known Member
Only in uk they are laid on with s&c and the strength of the mortar has nothing to do with this, it’s the suction they can’t overcome. Any other country in the world uses special adhesive, apart from Africa maybe .
mud
 

The Hobo

Well-Known Member
I've done many many S&C renders over a variety of substrates and much prefer it to bagged materials.
cant comment never done bagged gear mainly a Victorian internal man / if u ever up my way give u a few days free fishing pike and course
 
Either way book will always stop with applicator!

Ive almost come to the concluion that every job shoul be enough profit to allie to be able to be done again if needed!

people laughed at me when I have said that in the past :D
 

essexandy

The Lake Governor
Only in uk they are laid on with s&c and the strength of the mortar has nothing to do with this, it’s the suction they can’t overcome. Any other country in the world uses special adhesive, apart from Africa maybe .
Yeah I have seen the adhesive used locally a couple of times.
Overstrength brickies muck does cause lots of cracking. I remember a builder sending a sample of the local sand off to the manufacturer of Durox blocks and they recommended a 16:1 mix be used.
 

The Hobo

Well-Known Member
Yeah I have seen the adhesive used locally a couple of times.
Overstrength brickies muck does cause lots of cracking. I remember a builder sending a sample of the local sand off to the manufacturer of Durox blocks and they recommended a 16:1 mix be used.
think your right pal local sand is a big issue brought up in Lancashire work in isle of man for years been in Scotland last 35 sand is a big issue back in lancs on site work seen thermo walls split to fck cuase gear to strong
 

beader

Private Member
Yeah I have seen the adhesive used locally a couple of times.
Overstrength brickies muck does cause lots of cracking. I remember a builder sending a sample of the local sand off to the manufacturer of Durox blocks and they recommended a 16:1 mix be used.
4.1 mix will crack light weight blocks straight down a wall .But you can't explain to bricklayers. It's the same principle as render that the mix must be weaker than the substrate to be covered.
 

Arti

Well-Known Member
Yeah I have seen the adhesive used locally a couple of times.
Overstrength brickies muck does cause lots of cracking. I remember a builder sending a sample of the local sand off to the manufacturer of Durox blocks and they recommended a 16:1 mix be used.
16:1 holyshit balls that's weak
 

Rigsby

TPF Special Forces
Cracks are mainly a substrate issue ?
Can cracks be stopped by mesh ?
What’s your views


At first sight, it is presumed the applicator has got it wrong somewhere but that is not always the case.

The substrate can be wrong for example, the blocks have just been laid, wrong strength. But also structural cracking. I have seen plenty of that.

Weak blocks can be overcome but that's if we know. Concrete blocks look like concrete blocks, how are to know what strength they are? Then there is the ignorance of the client being told but they ignore your advice and you get told to get on with it.

As for applicator error? Yes, that is possible. base coats not cured enough, rendering tight up to expandable surfaces like soffits and frames. Wrong materials on the substrate like for example, Mono on cement particle board.

But when a crack happens and it is not obvious why then it is easy to blame the applicator and hold back payment. Unless the applicator can prove his innocence, then he is deemed guilty. A bigger problem is when the applicator knows what caused the problem and he is not believed. That is when the s**t hits the fan!
 

Spray

Well-Known Member
0011 hrs on a Sunday morning and Lox is up worrying about cracks in render. You need a week at the seaside, my lad. Maybe even a month.
an area to be rendered would be built with keyed bricks,laid on a bed of lime mortar, as these are now to expensive , it is all block work, built with a strong mix of sand and cement.
correct mate
 

Spray

Well-Known Member
At first sight, it is presumed the applicator has got it wrong somewhere but that is not always the case.

The substrate can be wrong for example, the blocks have just been laid, wrong strength. But also structural cracking. I have seen plenty of that.

Weak blocks can be overcome but that's if we know. Concrete blocks look like concrete blocks, how are to know what strength they are? Then there is the ignorance of the client being told but they ignore your advice and you get told to get on with it.

As for applicator error? Yes, that is possible. base coats not cured enough, rendering tight up to expandable surfaces like soffits and frames. Wrong materials on the substrate like for example, Mono on cement particle board.

But when a crack happens and it is not obvious why then it is easy to blame the applicator and hold back payment. Unless the applicator can prove his innocence, then he is deemed guilty. A bigger problem is when the applicator knows what caused the problem and he is not believed. That is when the s**t hits the fan!
Agree Jon !
 
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