Loft boarding advice sought: questions not answered i other

[murielmunki]

Hi, I read lots of posts and got the general idea but I still have questions. I’d appreciate any help offered.
I currently have one layer of rock wool type insulation running between the joists and a second layer running over the joist. To board the loft I intend to run battens at 90 degrees to existing joists and board over that so I don’t compress the second layer or insulation. There are no issues with height as house is old Victorian terrace with mahoosive roof space.
Questions:
Batten size: is 50 by 75 ml sufficient? Do I lay it on the short edge i.e. raising the height by 75 ml
What’s the best way of attaching the battens? Screw vertically down through the batten (big screws! And rout out to make screw head flat to surface, do I need to drill pilot holes first for that?), diagonally through batten into joist (will this run risk of splitting the wood?) or use angle brackets?
Do I need to attach the batten to every joist or will every other one be sufficient?
plan to space the battens 60cm apart. will this be suffiecient to support 18mm chipboard or will they need to be closer?
Thanks in advance

 

[Morrisman]

I'd simply pre-drill the battens with a clearance hole and then counter bore 25mm in with a bigger drill, so the screw head sinks well into the batten. Use 3" screws and lay the battens vertically. No angle brackets needed, no diagonal drilling, no routing.

Put a screw in every cross joint, wherever a batten crosses a joint, keep movement to a minimum, creaking etc. Once your flooring is screwed down the whole thing will be rock solid.

Personally I think 600mm is adequate between battens, as you will probably be using the tongue and grooved flooring, or whatever they call that taper locking edge thing they do.

I'd also screw the flooring down every 300mm along each batten, with a 40 or 50mm screw

I like to overbuild my stuff, so some might think it is overkill the way I'd do it.

I'm no builder, a mechanic actually, but I've thrown up a bolide or two in my time.