Extending a rendered block wall?

[jmhill]

Hi,

I’m extending a rendered block wall.

Do I need to set the new blocks back from the rendered face of the existing wall by the thickness of the render?

Should I hack off the render where the new blocks join the wall.

I will possibly re render the whole wall at some stage.

Thanks in advance.

Jon

 

[^woody^]

Yes and yes.

And if the new section may move or if you are not bonding the new wall in, then you need a movement joint else the render will crack.

 

[jmhill]

Yes and yes.

And if the new section may move or if you are not bonding the new wall in, then you need a movement joint else the render will crack.

Thanks it’s made of 140mm blocks laid flat I was going to use two stainless wall starters in parallel to tie it in to the existing wall will that be sufficient?

Jon

 

[^woody^]

Wall starters will almost certainly allow movement, so it would be better to install a stainless steel bead movement joint and seal it with polysulphide mastic