PIR direct to wall - fixings?

[duke666]

Sometime ago I posted about insulating my single block garage walls. With the advice received, we're about to start this using 75mm PIR direct to wall attached using 3 x 1 battens and plasterboard to the battens.

Question is, how should I be fixing this?

There is 100mm in depth before the block, so am I using 150mm screws & plugs or is there a better method?

Thank you.

 

[Ivor Windybottom]

Pretty sure you should have a freestanding wall, with a cavity. Like a timber-framed house. But this is ideal, perhaps reality is more of a compromise due to lack of space.

I'd be concerned about wood rotting and screws rusting, as well as the lack of damp-proofing.

 

[noseall]

Sometime ago I posted about insulating my single block garage walls. With the advice received, we're about to start this using 75mm PIR direct to wall attached using 3 x 1 battens and plasterboard to the battens.

Question is, how should I be fixing this?

There is 100mm in depth before the block, so am I using 150mm screws & plugs or is there a better method?

Thank you.

Single skin - I'd be inclined to place DPM membrane against the wall first, allowing enough extra to drape across the floor and ceiling a wee bit.
Then get some longer screws, fit the insulation tight against the polythene, then screw through the battens and into the wall, thus trapping the lot. Gonna be interesting guiding a rawl plug through 100 mm of insulation though.

 

[cdbe]

In my loft I fixed battens to wall then screwed through pb and PIR into battens. Screw length is quite critical (although I had a coat of render beneath the battens so had a bit of leeway before hitting brick). Maybe use 38x63 CLS and put some 40mm PIR between so as not to waste space.

I've underboarded a few ceilings with 100mm PIR and with care it's quite easy to hit the rafters with the long screws but I wouldn't fancy trying to hit plug holes!

 

[duke666]

Thanks for the replies, apologies for the delay in replying but I'm not getting notifications.