Jackoboard fixing spacing

[DavidJ]

I am fixing 12mm Jackoboard (strictly Contract board from CTD) to a studwall with 600mm studs. The board is 2400x600mm and I am laying the long edge horizontally along several studs.

I have fixed a screw into each stud along the horizontal edges (600mm centres) and also have fixed noggins 300mm up from the edge and attached a screw into this at 300mm offset to the edge screws. Please see that attachment for the stud pattern per 600mm square.

While the centre of the board is perfectly solid, if I grab the edge in the middle between two studs it is quite flexible which doesn't seem right.

The instructions I have found online seem to require a minimum of 5 screws per 1 square metre. The pattern I have used definitely exceeds this.

Can someone who has used these boards on a stud wall share what pattern of fixings they used?

 

[Flintstone]

You need 20mm board for 600mm stud spacing David,

 

[Old Mod]

http://www.dukkaboard.com/wp-content/uploads/2017/08/Dukkaboard-DTI2000.pdf

 

[Paul Smith]

12mm Jacko requires 300mm upright studding plus noggins.

 

[DavidJ]

Thank you. The guy at CTD said 12mm would be ok for 600mm studs. I should have double checked on here.

 

[Paul Smith]

JACKOBOARD® Plano construction boards can be fixed to timber or metal stud frames using JACKOBOARD® 36mm diameter galvanised steel washers and appropriate screws. If the frame centres are 600mm apart then boards of at least 20mm thick should be used. Fastening points must be arranged as per figure 3 or 4. If the frames are at 300mm centres then 10 or 12,5mm thick boards can be used. Fastening points must be arranged as per figure 5 or 6.

 

[DavidJ]

Thanks for the Jackoboard instructions PaulSmith. I'm going to get some 20mm board.

Comparing the Jackoboard and Dukka board instructions, the Dukka board says its ok to share fixings across the edge of two boards but the Jackoboard requires the edges of both boards to have their own screws (offset 50mm). This would require the studs to be over 50mm wide. My (existing) studs are a shade under 40mm.

Would the Dukka board method work on these boards?

 

[Old Mod]

Would the Dukka board method work on these boards?

It’s more about crushing the edges.
Tighten cautiously, and they’ll be fine I’m sure, although it’s not something I practice.
You can always help matters by using a PU adhesive between the boards on the edges as you join them.
The more fixings the better.

 

[DavidJ]

Speaking of not crushing the edges, do you leave the washers proud of the surface or let them pull into the board slightly so they're flush with the board surface?

Edit - found the answer on the instructions you posted:
"The insulation board discs must be sunk to the level of the board surface." so they have to crush the board a little

 

[Old Mod]

so they have to crush the board a little

If you’re not heavy handed, it’s easy enough to pull them in slightly.