Closing wide cavities

dfader

Hello all,
After much research (mainly denbydale passive house project) and drawing of different details I hope to have settled on a plan for closing my reveals - see attached.

I have played with the propietary cavity closers in details a lot but have come back to the plywood closer mainly because of the splayed reveals and the closers didnt really suit this.

A concern I have is fixing the plywood. I have shown a flexible strap to the back fixed to the external wall, I hope that to do this I'd fix this first, the flexible straps allowing rotate the plywood then bolt onto inner leaf - this might be difficult to achieve on site?.

I might be able to rely on the plywood and tapes only for airtightness as in the denbydale house.

Your views and advice, good or bad appreciated.

beyondpassive

Detail looks good, At (4) We specify cold pressed steel for the outer leaf restraint. (6)might be better as Timber, though this affect the installation thermal bridge, Is it Passivhaus certification standard.

We also noticed that (10) can some times be leaky unless the reveal airtightness extends under the mesh Key from the corner by >120mm. The scratch coat need to be done after the revals are lined with airtightness with the skim coat following when the reveal plasterboard is fixed. This sequencing can be difficult to program.

sinnerboy

The detail does not look robust enough to me. The outer leaf oversails the inner by about 200/250mm? At a place where additional cavity ties are required - you can't tie the leaves together.

The detail may be ok for windows of modest width only ( less than 1000/1200mm max ) . Beyond that I fear the outer leaf would end up being like the loose teeth in the old womens mouth.

I don't mean to sound caustic or negative for the sake of it. I get what your trying to do here. But I don't think the problem is solved yet.

dfader

sinnerboy wrote: »

The detail does not look robust enough to me. The outer leaf oversails the inner by about 200/250mm? At a place where additional cavity ties are required - you can't tie the leaves together.

The detail may be ok for windows of modest width only ( less than 1000/1200mm max ) . Beyond that I fear the outer leaf would end up being like the loose teeth in the old womens mouth.

I don't mean to sound caustic or negative for the sake of it. I get what your trying to do here. But I don't think the problem is solved yet.

Thanks Sinnerboy,
Thants a valid concern - only solved by putting the squaring the reveals so the wallties can go closer to the ope. Or is it possible to incline the wallties (use longer ones offcourse and run them at an angle parrallel to the plywood). Really want to splay the reveals - to let in more light, what with the walls being so thick.

mfceiling

Send fclauson a PM.

I'm sure he faced a similar scenario as yours.