18mm ply shelf strength

[Lower]

I'm in the process of building a shelving unit at the end of a narrow room that we intend to use a cloakroom. The shelves are for shoe and boot storage.

I'm currently battening the walls to carry shelves made of 18mm ply. The shelves will be 90cm long and 40cm deep.

At the moment the design of the unit is such that the shelves will only be supported at either end. I'm trying to get away from battening the back wall underneath the length of the shelf.

Is 18mm ply going to be strong enough for me to do this? I can't imagine that the load on each shelf is going to be more than 10-15kgs spread fairly evenly along the length as shoes and boots aren't that heavy!

Thanks in advance.

 

[SammyInnit]

I'd imagine the likelihood of sag is there. However best way to find out is try it. If you're not adding support to the back wall perhaps fix something to the underside of the shelf to keep it from sagging. Same material you're using for example.

The ply will take the weight no problem but that's what you need to avoid, the potential sag.

 

[HERTS P&D]

Fit a 40mm timber lip on the front, it will stop it from sagging.

Andy

 

[endecotp]

Here's a datapoint for you: I have a bookcase with shelves that are 870 x 300 x 20 mm veneer chipboard supported only at the ends and they sag just a couple of mm when loaded with books. So I think you'll be fine.

 

[Deleted member 174758]

Use the Sagulator calculator to find out how much sag you are going to have. IMHO 870mm is pushing it unless you add deeper lippings to reduce the sag - even then it could be too much to tolerate

 

[Lower]

Sagulator (great steer by the way!) says 0.5mm sag if I fix the ends. 2.5mm if the ends can float. Double that in time based on 10kgs per foot loading over a 1m span. 30kgs of loading is probably way too much though as the shelves will only carry shoes.

Solid timber edging on the front edge would give me a nicer finish and stiffen things up a bit more so might go that route

 

[foxhole]

I doubt you could get 10kg of shoes and boots on a shelf that size.

 

[HERTS P&D]

They might be concrete boots.

Andy