Air hooks for Radon membrane

[flanagaj]

I was given the following schematic diagram by St Goblain in relation to their suggested approach for a Radon membrane.  Just wondering whether anyone know how you go about suspending insulation in the cavity with using wall ties?

Visqueen are also showing a similar detail of insulation just suspended in thin air directly below the cavity tray.

[BadgerBodger]

From experience this wouldn’t actually be hanging like that below the tray. That bit isn’t really their bag so they won’t pay much credence to it. I used Kingspan green guard full fill below DPC and PIR full fill above. The thermal bridge in the blockwork was dealt with by marmox blocks. 

 

 

The detail on the left, is that a tanking product running up to/under the tray? Assume so as EGL is above IGL
 

 

[Redbeard]

9 minutes ago, BadgerBodger said:

The thermal bridge in the clockwork

Messrs Bing and Hornby will be turning in their respective graves! ☺️

[Nickfromwales]

1 hour ago, Redbeard said:

Messrs Bing and Hornby will be turning in their respective graves! ☺️

I sorted the typo, sorry, so now you look loopy. Lol. 

[Mr Punter]

Be interesting to see the as-built version of the drawings.  That is a lot of different products being applied at the substructure level.  The insulation could be held in place with wall ties, although you could just use blown beads.

[dpmiller]

why don't you just put the radon membrane lower down, straight across the whole area before the cavity begins? Then you can deal with damp above it at your leisure...

[flanagaj]

49 minutes ago, dpmiller said:

why don't you just put the radon membrane lower down, straight across the whole area before the cavity begins? Then you can deal with damp above it at your leisure...

The membrane isn't the issue.  It's the cavity tray that has to be there.  Maybe full fill under compression will happily stay suspended in the cavity.  The drawing has a vertical membrane against the inner leaf, so using wall ties will mean breaching said membrane.

[Redbeard]

13 hours ago, Nickfromwales said:

I sorted the typo, sorry, so now you look loopy. Lol. 

@NickfromwalesWhat do you mean 'look'?!

 

(I did spend half a minute looking for the typo in my post though! Got there!)

 

[Spinny]

Here is what was done on my extension - see pics.

 

The Radon barrier - which also functions as a DPM was run wide as a continuous piece. So it runs across underneath the insulation and heated concrete slab above, through the inner leaf of the wall, then vertically up the outside of the inner leaf, then horizontally across the insulated cavity and the outer leaf. A seperate DPM is installed across the inner and outer leaf so sits immediately on top of the radon barrier on the outer leaf.

 

Cavity insulation below the radon barrier was XPS as this was considered more robust should any moisture get into this part of the wall, then PIR above the cavity tray formed from the DPM.

 

I am not sure why your architect seems to be specifying so many different membranes and joining them in the way shown in your drawings, when I would have thought one continuous piece could be used. I would encourage consideration for the practicalities of what builders are going to actually achieve on site. I think it is going to take a very - perhaps uniquely - diligent and conscientious groundworker/brickie to continuously join two membranes all around the perimeter of a build ?