scratch coat render on block work outside wall cracking

[halfahippy]

HI I have done a scratch coat on a wall the mix was 4.1.1 plastering sand, blue circle premium cement and lime with a glug of water proofer. it is showing some cracks not major ones but still cracks which I believe? is because I stupidly used the premium cement instead of the ordinary. For the top coat my mix is? going to be 5.1.1 with a glug of water proofer but this time with OPC not the premium. Any advice please will I get away with the cracks or will they come through in the top coat? Other than the few cracks the scratch coat is sound I dont really want to have to hack it of and start again if I can help it. Also before the scratch the wall was treated to a coat of rendagrip which again took really well no problems, any advice/tips would be great thanks.

 

[bobski]

HI I have done a scratch coat on a wall the mix was 4.1.1 plastering sand, blue circle premium cement and lime with a glug of water proofer. it is showing some cracks not major ones but still cracks which I believe? is because I stupidly used the premium cement instead of the ordinary. For the top coat my mix is? going to be 5.1.1 with a glug of water proofer but this time with OPC not the premium. Any advice please will I get away with the cracks or will they come through in the top coat? Other than the few cracks the scratch coat is sound I dont really want to have to hack it of and start again if I can help it. Also before the scratch the wall was treated to a coat of rendagrip which again took really well no problems, any advice/tips would be great thanks.

Get some pics up of the cracking to get a better idea.

 

[Monkey Boy]

Just crack on

 

[essexandy]

HI I have done a scratch coat on a wall the mix was 4.1.1 plastering sand, blue circle premium cement and lime with a glug of water proofer. it is showing some cracks not major ones but still cracks which I believe? is because I stupidly used the premium cement instead of the ordinary. For the top coat my mix is? going to be 5.1.1 with a glug of water proofer but this time with OPC not the premium. Any advice please will I get away with the cracks or will they come through in the top coat? Other than the few cracks the scratch coat is sound I dont really want to have to hack it of and start again if I can help it. Also before the scratch the wall was treated to a coat of rendagrip which again took really well no problems, any advice/tips would be great thanks.

You haven't stated what substrate you're applying to, that mix could be completely wrong.

 

[halfahippy]

You haven't stated what substrate you're applying to, that mix could be completely wrong.

Sorry thought I had here is a pic of the blocks a type of pumice block

 

[halfahippy]

Get some pics up of the cracking to get a better idea.

I will get some later of the cracking

 

[halfahippy]

Just crack on

Im hoping to lol

 

[Cockney]

Another wrong mix thread.

 

[halfahippy]

Get some pics up of the cracking to get a better idea.

I will get some later of the cracking

Hi Bob not the best pics but hopefully you can see it ok

 

[halfahippy]

Another wrong mix thread.

What mix should I have done?

 

[bobski]

Hi Bob not the best pics but hopefully you can see it ok

I wouldn't be overly concerned

Not great but not serious.

Look like shrinkage, as long as it's sound you should be ok. The cracks arent continuous are they?

They look real short.




What blocks were they?

Did you do it in strong sunlight or did the sun hit it?

 

[halfahippy]

Thanks for your reply, they are a pumice type concrete block, done on a cloudy day no sun. The cracks are short so hopefully it is just a bit of shrinkage definitely sound I just hope it doesn't happen on the top coat.