Concrete Anchors - Help with hanging from ceiling

[SelfBuild88]

I am looking to install a hanging shelving system from the ceiling of a leasehold flat. As shown in this image:

The ceiling to the flat is a painted concrete slab, which then forms the floor to the flat above. I therefore cannot bolt through the slab and install fixings in the flat above. But assuming this slab is 200-300mm thick I should have no problem fixing concrete anchors 100mm in to this.

I appreciate that there is an issue with the arrangement of leasehold in relation to fixing in to the structure of the building. But assuming I can negotiate this I wanted to understand if this would be possible in principle or if it is likely to cause a problem.

The shelving unit I want to install is built from ply, the top panel which I would fix to the ceiling measures 2400mm x 450mm. In theory I could install multiple concrete anchors in pairs down it's length. Many of the anchor products claim to hold 60kg from a single point, so in principle installing as many as 10 fixing points should help to distribute the weight and should be more than sufficient. I'm keen to know if you think this would be possible or is it too risky to rely on anchors to hold a system such as this?

 

[Newboy]

Before you do anything you need:

1) Permission from the freeholder
2) Details of the construction

There are a number of possible types of floor slab construction (very few of which will be of the thickness you've indicated). You need to consider the possibility of buried services and rebar within the slab

 

[SelfBuild88]

Newboy, thank you very much for the quick response

I appreciate the freeholder's permission is vital. With regards to the slab - there are no buried services, these are surface mounted above. I suspect the slab is reinforced so we will have to locate any rebar. Can I ask why you questioned a thickness of 200 to 300mm - I thought this was typical for reinforced slabs, if not 400 to 500mm.

We have another sitting room with a lower ceiling where we could install a similar shelving system, but the ceiling is a suspended plasterboard fixed to joists. Could I ask if there are comparable loading issues if we screwed the shelving in to timber joists instead? Are spring toggles/umbrella fixings in to plasterboard a waste of time?

Thanks again for your help, I'm regretting showing my partner this image as she is now set on a hanging shelving system!

 

[Steve]

You cannot hang that thing off toggle clamps. Forget it. Must be thick joists. If the joists were put there for the ceiling alone, they may not be up to the job.

Suspended concrete has to be lightweight so its normally not very thick but has strengthening properties. Usually rebar, and/or it may be poured onto a metal corrugated sheet. You'd see the latter. It may also have fibres in it. Nylon or other polymers are common. Half a metre thick of concrete? The slab weight would be immense. A thickness of 100mm is more likely.

I'd forget the whole idea. You can still have a room dividing book case, just stand it on the floor instead.