Sealant for joists in blockwork

[SuperPav]

Hi all, what's the recommended sealant/mastic to use for sealing joist ends built into blockwork in a cavity wall for air tightness? I can get to both sides of the leaf (inside and outside) so can seal from both sides. I would've thought something non-setting is better, but if normal silicone or EB25 or CT1 or whatever posh stuff is recommended I'm happy to get it.

 

Thanks

[nod]

49 minutes ago, SuperPav said:

Hi all, what's the recommended sealant/mastic to use for sealing joist ends built into blockwork in a cavity wall for air tightness? I can get to both sides of the leaf (inside and outside) so can seal from both sides. I would've thought something non-setting is better, but if normal silicone or EB25 or CT1 or whatever posh stuff is recommended I'm happy to get it.

 

Thanks

Just about to use a couple of boxes 

Great for acoustics and fire protection 

[tonyshouse]

tonytray is 100% and permanent ,  not only the joist ends that leak but the blocks themselves, any cracks and those can develop later, joinsbetween blocks, bed joints and joists can shrink and move too. 

[nod]

10 minutes ago, tonyshouse said:

tonytray is 100% and permanent ,  not only the joist ends that leak but the blocks themselves, any cracks and those can develop later, joinsbetween blocks, bed joints and joists can shrink and move too.