Extending joists for floorboarding an insulated loft

[mainy]

I plan to add floorboards to our loft. At the moment it has 270mm of insulation, the bottom layer running parallel with the joists, the top layer running perpendicular. After much research I've decided to extend the existing joists and run some 2x4 perpendicular. I can then board over the top all of the insulation.

Because I don't want to lug around long heavy wood (nor could I transport them) and don't know the full dimensions of my loft, I am planning to get the 2x4 in lengths of say.. 3ft. How can I reinforce, or join these planks of wood together in the loft?

Would something like these mending plates be satisfactory?
http://www.wickes.co.uk/invt/215034
http://www.wickes.co.uk/invt/164452

Or am I best just staggering the 2x4 next to each other and putting a big bolt through them both?

King regards,

 

[tony1851]

Joining them with the toothed plates will be difficult insitu.
Why not overlap them by a few inches and screw them together? No need to use 'big bolts'.

 

[mainy]

Ok, perhaps that is the route I take. I was wondering if overlapping would cause any issues with placement of the t&g floorboards.

May I ask why toothed plates (or the mending plates) would be difficult?

 

[tony1851]

May I ask why toothed plates (or the mending plates) would be difficult?

If you butt the ends of the short pieces together and try to hammer the toothed plates on, possibly the timber will flex too much and you might not be able to hammer the plates firmly home.

The screw plates might be better, but you would need - say - two to each connection (one either side) and a lot of screws.

 

[mainy]

Ok. Thank you tony. I'll go ahead with staggering the timber.