SBR mix Ratio onto 7Nm concrete blocks

[St Andrew]

Hi,

My question is can you please tell me what ratio of mix I should use for SBR when rendering concrete blockwork and also some areas where existing scratch coat is present?

BAL's date sheet has lead me to the following:

Slurry coat 1:1 cement and SBR let down with water up to 1:1:1 and brushed on.

· Whilst slurry coat is still tacky apply scratch coat (4:1) ,mixed with water/SBR mix (5litres of SBR, but this seems to much to me?). Allow this to dry.


· Render coat; (5:1), mixed with water/SBR mix (5litres of SBR?) Then wet dash on this.

The amount of SBR seems excessive, can you guys tell me what your doing?

 

[Dropsalot]

Now then matey.......The pessimist in me is gonna suggest that the ratio often depends on whether you're buying the sbr or.......selling the sbr.....

Me, I damp the blocks to get rid of the dust, one part sbr to two parts water, and a shovel of cement, nice little stir up, slash it on. Once it's tacky, scratch it.

 

[zolco]

Now then matey.......The pessimist in me is gonna suggest that the ratio often depends on whether you're buying the sbr or.......selling the sbr.....

Me, I damp the blocks to get rid of the dust, one part sbr to two parts water, and a shovel of cement, nice little stir up, slash it on. Once it's tacky, scratch it.

Pmsl

 

[theclemo]

Why would u use sbr on concrete blocks

 

[St Andrew]

This was my thought,if I was selling it I'd probably be saying 'use more!'
So you wouldn't bother to put any in the coat before hitting it with wet dash?

 

[St Andrew]

Why would u use sbr on concrete blocks

I probably didn't put enough info in the original post, Its already been coated once (not by me) and basically fell off

 

[Dropsalot]

Ahh well there now then there.....mix it up like thin skim, and slop it on.....twice...then scratch.
Cheers.

 

[flynnyman]

I probably didn't put enough info in the original post, Its already been coated once (not by me) and basically fell off

They probably didn't coat it when it was tacky or still wet, is the slurry coat still visible?

 

[St Andrew]

They probably didn't coat it when it was tacky or still wet, is the slurry coat still visible?

They didn't put anything on it before coating, but I suspect they over doped every thing except the wet dash coat. The bit in my question about the mix is what I'm proposing to do to put it right.

 

[Beenereb4]

Do you realise the 4:1 and 5:1 are your sand to cement ratios

Hi,

My question is can you please tell me what ratio of mix I should use for SBR when rendering concrete blockwork and also some areas where existing scratch coat is present?

BAL's date sheet has lead me to the following:

Slurry coat 1:1 cement and SBR let down with water up to 1:1:1 and brushed on.

· Whilst slurry coat is still tacky apply scratch coat (4:1) ,mixed with water/SBR mix (5litres of SBR, but this seems to much to me?). Allow this to dry.


· Render coat; (5:1), mixed with water/SBR mix (5litres of SBR?) Then wet dash on this.

The amount of SBR seems excessive, can you guys tell me what your doing?

 

[Squarehead]

I've always wondered why they state to use so much and I've always ignored that. A good glug is what I put in and suffices.

 

[St Andrew]

Do you realise the 4:1 and 5:1 are your sand to cement ratios

Yep

 

[St Andrew]

I've always wondered why they state to use so much and I've always ignored that. A good glug is what I put in and suffices.

Same as me, do you only put SBR in the slurry applied prior to the scratch?

 

[Squarehead]

Same as me, do you only put SBR in the slurry applied prior to the scratch?

Put it in each coat with render mesh, tough as fuckk.

 

[St Andrew]

OK, thank you all.
From what I've read here and having canvassed local opinion I think I'm going to go for the following if any body what's to comment please feel free (who ever he is?)
On the area's I've taken back to bare block I'm going to make a slurry coat: 1 sand 1 cement and 1 SBR let down with water to make easy to apply. Damp down the surface with water and apply slurry coat, when it goes tacky apply scratch coat 4 :1 and then let this dry for a week. Then a coat of 5:1 let this go till its ready and hit with the wet dash.
For the areas where the scratch has stayed on OK, I'm going to put a key into it using a Refina scabbler (C6) wheel, then slurry coat this and put on the last render coat and hit with wet dash.

 

[St Andrew]

Put it in each coat with render mesh, tough as fuckk.

Sorry Squarehead are posts passed each other in the ether.