# Forum Home Renovation Rendering  fixing blueboard to concrete block

## Stan 101

I've a 190mm concrete block wall with 150mm breeze / vented blocks in the centre of the walls; common to 50's style places up here. I want to render but first will cover the breeze blocks with blueboard. 
I've had conflicting info on direct fixing. I don't want to batten as the blue board would then be proud of the main blockwork and I still want to have the breeze block section rebated to create a framed area. 
I have been told direct fix with sika adhesive or liquid nails and then 600mm centres with masonry nails. 
Has anyone successfully fixed blueboard to concrete and if so how? 
Regards,

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## Stan 101

Just in case anyone else is interested in future: 
Called James Hardie and they had no tech specs on fixing to concrete I went ahead and used two tubes of sikabond per 2400x1200 sheet and concrete nailed into the fillet areas of the breeze blocks with Ramset 25mm concrete nails at approximately 600mm centres. 
I needed to be very precise on the nail position as the first few attempts at nailing simply chipped out the breeze blocks. I measured each fillet centre from the inside of the wall and transposed to the blueboard. 
 I'll seal around the perimetre of each sheet with sikaflex and with the internal face of the blockwork still open I have no concerns on constant damp. 
I prepped by using a grinding disc to take the burrs of all the edges of the breeze blocks and excess morter that had been left when the wall had originally been built. I also gave the painted areas a good goingover till I could see the porus section of the blocks. 
The result is good with no hollow sound when hitting the blueboard. Overall the result was a good one.  
Cheers,

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