Sand and cent help needed.

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Jackospread

Jackospread

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Currently on a job in winsford.
Sand and cement over old brickwork. Brickwork has rough jagged finish so should be enough key. First key coated with 3-1 sand cement with 250ml cementone waterproofer and glug of cementone plasterciser in each bucket water. went in really fast. Topped yesterday with 4-1-1 sand cement lime went in fast again kept on top of it though nicely. Turned up today and I could have died. Never had this before The cracks were everywhere. Never known it go in so fast over brick. I've prepped the next area with 3-1 water to sbr and gonna give it 1-1 water to sbr tomorrow before I chuck scratch coat on.
Any advice welcome! The bricks are very dry and am I doin the right thing with sbr? Used it in past and it's been great no problems.
 
Id be inclined to add sbr in the scratch,and a 4.1
as a scratch.
Im sure there will be plenty of options from others.
Id also hose down the wall before topcoat,esp in this heat
 
Did you let the scratch coat cure before you top off?? Did you have and fibres in ya gear??. I always SBR slurry coat old brickwork before i scratch ( Or Scud it as Irish would say)
 
Artisan998 said:
Did you let the scratch coat cure before you top off?? Did you have and fibres in ya gear??. I always SBR slurry coat old brickwork before i scratch ( Or Scud it as Irish would say)
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No fibres mate. And the scratch was done sat then topped on Tuesday. Was bone dry. Cheers. Sbr slurry? What ratio. And on top of sbr'd wall? The previous plasterers scratch had been hacked off because his topcoat had cracked. Looked very sandy too
 
1 guage of sand/ 1 gauge of cement into 50/50 sbr water mix and just brush it on I would use this rather than just your SBR/water mix. What sand are you using?? i decent plastering sand is what i find best. Some lads on here mix there plastering sand with either sharp or building. Im sure you'll get soem other ideas before the night is out marra.........:RpS_thumbup:
 
use rendaid to nutrilise brick apply with roller to get stipple affect- scratch 5-1-1sand lime cement--float coat 5-1 sand cement use sharp sand
 
I never put lime in scratch only in the top coat. Making your own slurry is alot cheaper than rendaid
 
cheap isn,t always the best when dealing with brick and the reason for using lime in the scratch i find it bonds better to rend aid and has less water retention and reduces the shrinkage in the finale coat with less chance of crazing ----i might be wrong but it seems to work for me
 
idler said:
cheap isn,t always the best when dealing with brick and the reason for using lime in the scratch i find it bonds better to rend aid and has less water retention and reduces the shrinkage in the finale coat with less chance of crazing ----i might be wrong but it seems to work for me
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welcome to the forum Idler, maybe you would like to introduce your self and share a little backround info etc, do you use much weber gear?
 
Cheers lads. Did an sbr slurry. scratched 3-1 next day. Topped it today. Went in like a dream. Sbr rules ok. ;)
just out of interest what's your favourite waterproofer lads?
 
allyb said:
Because it counteracts what the water proofers doing mate that's what I were taught anyway
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I can see why someone might say that but I dont put that much waterproofer in the scratch anyway, I damp the scratch down before topping.

If you are finding that it is countering the waterproofer I would say just add more. Lime in the scratch vastly improves workability and stops a certain amount of cracking.

You want that sh1t nice and creamy. :RpS_cool:
 
DannyMac said:
I can see why someone might say that but I dont put that much waterproofer in the scratch anyway, I damp the scratch down before topping.

If you are finding that it is countering the waterproofer I would say just add more. Lime in the scratch vastly improves workability and stops a certain amount of cracking.

You want that sh1t nice and creamy. :RpS_cool:
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Does the lime not create loads of suction for the top coat Danny???
 
No, I use half a bucket of lime and third of a pint of waterproofer in each mixer full. Unless the sun is beating down on the wall, it normally needs just a light even spray/splash of water and you have plenty of time with the top coat.
 
DannyMac said:
No, I use half a bucket of lime and third of a pint of waterproofer in each mixer full. Unless the sun is beating down on the wall, it normally needs just a light even spray/splash of water and you have plenty of time with the top coat.
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Roger...........:RpS_thumbup: do you top off with lime as well though
 
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