Floor insulation - hold in place?

[markyyyyyy]

another question regards my timber frame base for log cabin

what is the cheapest and most effective way to secure 70mm celotex insulation board inbetween the floor joists - there will be a void underneath as it's a timber frame resting on pads, so i obviously dont want the insulation to fall through.

i am using 2x4 joists set @ 400mm centres if that makes any difference

Was thinking a couple of nails put into the side of joists with a cm or so protruding to stop it falling through? would that work?

 

[Notch7]

I used small timber battens 32 x 15 or similar - I screwed them in place before laying the joists.

 

[JP_]

I put trellis poles (anything will do, I just had loads spare) perpendicular to and under the joists so i can use the full height of the joist. Any gaps between insulation and joists filled with foam that helps fix it in place too.

 

[foxhole]

I just tap a couple of nails in either side and tap insulation in place holds very firm.