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.

200mm concrete screws?

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.

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, 20242 yr by Conor

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

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

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

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

Try corefix red fixings

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.