fixing timber batten to thermalite block

[scfc151]

Ive had an extention built with thermalite block. building regs require me to insulate internal walls with 25mm pir board.

my plan was to use 25mm battens and board inbetween. then fix plasterboard over the top.

im wondering what is the best way to fix the battens? I know the blocks are soft so concerned about using expanding plugs incase the block crumbled.

my plan was to screw straight in with a coarse wood screw. maybe even with some construction adhesive on the batten. any advice appreciated thanks

 

[^woody^]

Helical nails

 

[Notch7]

Fischer fur frame fixings are quite good.

Drill with hss bit non hammer gently without rocking -not easy when drilling into polystyene

 

[23vc]

If you go easy on the drilling, as the blocks hardly require any effort at all, and keep the holes on the small side then no reason you can’t just use normal red plugs and say 5x80 screws. Go easy when screwing them in too (no impact driver)

 

[^woody^]

Is there any particular reason why you two would prefer to drill and plug into the worst blocks in the world for getting a fixing by drilling and plugging into?

 

[23vc]

I’m a cheapskate who likes a challenge?

 

[scfc151]

cheers lads. the room is 5m x5m with a vaulted ceiling so lots of battens. metal plugs will literally cost hundreds. id pay it if i knew it was the best option. ive never used helical nails ill look into that

 

[rsgaz]

I don't see the problem with screw and plug fixing into Thermalite. Notch mentioned Fischer FUR, their own testing, into the weakest 2.8N block, yields 2.23kN ultimate pull-out strength per fixing...

https://www.fischer.co.uk/-/media/f...rate-reports/documents/thermalite_report.ashx

If I was doing it, I'd be using normal(but good quality) red plugs also. If you really want to go to town, two red plugs knocked into the same hole. Red plugs are 1.25 inches and your batten is 1 inch, so drill depth of 2.5 inch into the block with 3.5 inch screws, number 8 or 10.

Just one fixing like that, I assure you you can hang your weight from it, I've done it many times to show a non-believer!

 

[Draughtsman]

What about drywall screws? Long ones, they seem to bite if you don't over tighten. Pre drill the batten but at a bit of an angle, not perp. Not putting the screws in perp to the wall seems to help if you're fixing to something with the structural integrity of a Farley's rusk.

I use 60mm drywall screws to fix knock out boxes in to thermalite but screw them in different angles, never perp, batten would probably need longer, maybe with small pilot but pilot NEVER drilled on hammer action.

Plugs in aerated? It might work, there are always 2 chances I suppose.