Where to buy sturdy racking/shelving for the shed?

I got my Dexion long-span racking from here:

It's bombproof.

B&Q do good shelving units (see link https://www.diy.ie/departments/form-exa-5-shelf-hdf-steel-shelving-unit-h-1800mm-w-1200mm-d-450mm/1710951_BQ.prd for one of the sizes). I have a couple of them and they go together fairly easily and bear weight well.

In sheds that get damp I like plastic shelving. I have a few of something like these

If you need different shelf heights you can cut the plastic tube uprights down.

A damp shed is a useless shed.

This stuff is good: https://www.ikea.com/ie/en/p/hyllis-shelving-unit-in-outdoor-00278578/

I have a lot of sheds 6 in total. The wooden sheds are OK, lined and well ventilated but the old stone sheds would take a massive amount of work to sort.

I use a lot of waterproof toolboxes and ziplock bags for anything that will rust. I'm doing a spring clean atm and dumping a lot of stuff I'll never use and is just going rusty.

@The Continental Op wrote

That sort of proves my point though, Timmy Six Sheds 😀 It's better to have fewer dry things than lots of damp things.

FWIW my racking is in a damp-ish unheated basement and the chipboard shelves are not an issue. If it was any damper the space would be too damp to store anything. Rust isn't a problem so far but anything I put in there that absorbs moisture gets ruined.

In other words, if the space is too damp for chipboard shelves it's also too damp to keep most things that you would want to put on the shelves.

Highly recommend this one and the longer 28inch version for longer tools like hand saws. I keep all my daily use tools in one in an open sided barn and with a quick mist over of WD 40 before closing it's kept woodworking tools perfectly for years.

There is also this DeWalt system which uses the same type of seal (no surprises as they are the same company)

Then for anything that won't rust I use an assortment of boxes that aren't totally waterproof but don't let drips in. I particularly like the black (recycled plastic) Really Useful Box range

You can't get them anymore afaik but always found the curver tough range to be the rolls royce of storage boxes when it comes to strength. Again not actually waterproof but nothing gets in.

I think you might get the musty odour still with waterproof boxes unless you open them up occasionally. What I have found is anything that already has a musty smell will stay that way and even spread the smell in a sealed box but stuff that doesn't smell normally stays fine.

Try Rackzone in Ballinasloe for solid shelving (like a supermarket) Think they deliver as well

I think the debate about damp and sheds is multifactorial- where is the shed located, exposure, type of construction, ventilation, heating, type of stuff stored etc. I live in the midlands, I've a decent shed, with good dpm etc, intermittent heating and ventilation (when I'm working in it) and I don't store wet tools or gear in it, but at times it will feel damp because our climate is damp! There's been no "drying weather" at all this autumn/ winter so everywhere just feels damp, god the weather in this country can get you down at times, sorry, rant over...

Will second

excellent quality, a little pricier than the Screwfix/B&Q stuff but way better quality. Have a garage kitted with their stuff a couple of years and a friend did the same recently, also pleased with what he got.