How Do I Fix 3 x 2 timbers to dot and dab plasterboard

[Heatseeker]

I have 20mm expanded polystyrene plasterboard dot and dabbed to external brick wall which is dry and has been fine for 15 years.

 

I don't want to remove this, but to add 3 x 2 studwork infilled with celotex and then insulated plasterboard over the timber.

 

How do I fix the 60mm timbers to the existing wall?  I can't find any fixing long enough?

 

Thanks.

[jayc89]

200mm concrete screws?

[Super_Paulie]

did the same myself last week. 6mm pilot hole straight through the timber into the brick and then impact drive concrete screws all the way in, rock solid.

[Conor]

180 or 200mm concrete screws. You'll need an SDS drill with a 6x250mm bit and a decent impact driver for driving the 7.5mm screws in. Also get a bag of window packers so you can everything nicely straightened out.

Edited May 15 by Conor

[Heatseeker]

Thanks very much for the replies.

 

So - drill through timber into brick with 6mm SDS masonry bit.  Need to hire a SDS drill.  My driver is DeWalt 18V XR - good enough do you think?   And these screws....?

 

https://www.screwfix.com/p/easydrive-tx-countersunk-concrete-screws-7-5mm-x-180mm-100-pack/9569h

[Super_Paulie]

i used these shims, pretty good as they could hang onto the screw while you drive it home.

 

https://www.screwfix.com/p/broadfix-assorted-plastic-shims-medium-200-pcs/80408

[Mr Punter]

I have been using the Atlas concrete screws and they seem good and less than half the price of screwfix:

 

https://www.dryvergeandrooflinedirect.co.uk/products/atlas-zyp-concrete-screws?variant=40578226651326

[nod]

Make a stud partition and fix to the floor and ceiling You don’t need to fix to the wall

[Lofty718]

Try corefix red fixings

[Super_Paulie]

13 hours ago, nod said:

Make a stud partition and fix to the floor and ceiling You don’t need to fix to the wall

in my own situation I have a crappy old lath and plaster ceiling above with no joists to go into as they run in the same direction as my stud. What i did was concrete screw timber directly to the brick wall behind and then frame out from there. Double the timber but it makes it sturdy enough with a 100mm void for services and sound deadening. Not sure if the original poster is in the same situation.