Shelf board - which is stronger

[LaserTam]

Putting a shelf into a storage area, cosmetically doesn't matter what it looks like. it will be appx 128cm x 75cm and will be rested on battens on three sides, one of the long sides will not be supported.

So, I am thinking either a sheet of MDF or maybe OSB - question is which of these would be most rigid so it doesn't bow too much along the un-supported length? Suggestions on thickness, I was thinking 12mm.

[RC1]

depends whats going on it but osb better than mdf but ply would be better than both. just be sure to spread the load

[Renovation]

What is going on the shelf ?

Even light weight will cause both those to bow at 12mm.

I tend to over engineer but I'd screw a 3x2 CLS to the front edge of an 18mm ply if the shelf was in my garage.

[B17NNS]

I'd be thinking more along the lines of some 18mm ply.

[Simpo Two]

Over 128cm most things will sag, especially MDF. Probably the best I can think of is solid wood, but I think anything is going to sag with time if you put weight on it. If it was me I'd screw a batten under the front, or maybe even a small angle iron suitably covered up.

[LaserTam]

Ummm. Thanks for replies. As for whats going on it - anything my wife throws at it probably, so need to prepare for the worst. So I am now re-thinking. So perhaps a) thicker ply as suggested b) maybe the batten screwed to the board as suggested and/or c) I could put a vertical bit of timber from the unsupported edge down to the floor to provide the support.
Cheers.

[Rosscow]

18mm or 25mm ply will be better than MDF or OSB.

You have battens on 3 sides so a piece of the same timber along the underside front edge will be fine.

That said, if it's just everyday 'stuff' that isn't particularly heavy then 18mm MDF will be fine.

[mgtony]

As said, 18mm ply or MDF with a batten fixed under the front edge and another one halfway back will most likely be ok, you could notch these into the side battens on the wall. Screwing the shelf down along the back could also minimise deflection.

[Renovation]

If you are willing to fix a batten to the front and a vertical mid span then you can save money on the sheet and use chipboard.