18mm plywood subfloor with 450mm joist centres?

[iwilson16]

Is 18mm plywood strong enough to use as a new subfloor in a Victorian flat where the joists are at approx 450mm centres (joists are approx 80mm thick), and every edge would be supported?

I'd lay boards in same direction as joists, and cut boards lengthways such that both long edges were over the middle of a joist, and add noggins between the joists where boards met at the short end.

I know 22mm plywood would definitely be fine, but its a b*gger to handle and cut by myself (needs carried to second floor).

I definitely dont want to use chipboard. I prefer square edge plywood so its easier to lift boards if needs be in the future. Room is approx 4m x 3.5m.

Thanks
Ian

 

[John D v2.0]

Can't see you'll have any issues. Just make sure you get the proper structural ply not some cheaper option. Not all ply is created equal, both the glue and the wood have to be good enough, together with the way they're made in the factory.