shed / workshop floor

[nodeward]

so looks like ill be moving house fairly soon so i need to build myself a decent workshop/shed to house my increasing collection of tools. now as much as i am looking forward to this project (the misses would probably say a little too much!) the only thing i seem to undecided on is the floor.

its going to be a concrete base and the stucture will be wood but what im wondering is should i build a wooden base, beams accross the floor with ply on top, like a normal shed on just go straight off the conrete. i have some quite weighty stuff and looking to get a myford sized lathe if there is room but nothing that will need a crane to get it in!

any pros and cons? the only thing i was worried about was wether it would get damp straight onto concrete?

 

[cumbriasteve]

Straight off the concrete, lay the slab on a damp proofing membrane, 4" thick will manage anything you can fit in a shed.

 

[rtbcomp]

Would it be advisable to bury a reinforcing mesh in the concrete?

 

[normspanners]

The problem with a wooden floor is the cavity, it is somewhere nice and dry for the vermin to nest, then they think I wonder whats up there ?

 

[nodeward]

i was think that as well ^

 

[cumbriasteve]

Would it be advisable to bury a reinforcing mesh in the concrete?

It never goes wrong to include some, a lot depends how good the foundation is below the slab.

 

[500e]

If you use mesh remember it goes IN the slab at least 25 mm, not between the foundation & slab.
Last week this builder had it totally wrong, membrane on un compacted stone mesh on top of membrane, we caught them before they laid the floor, would have been worse if we had found it after it had dried & then made them remove & start again, to say we were not happy could be the understatement

 

[brightspark]

If you use mesh remember it goes IN the slab at least 25 mm, not between the foundation & slab a I saw the other day this builder had it totally wrong membrane on un compacted stone as well.
They were not happy budgies we caught it before they had laid all the floor still would have been worse if we had found it after it had dried & then made them remove & start again

normaly u compact the base dolomite ect then blind it with sand then lay the visqueen sheet on top lol cowboy builders get away with it if u dont know the score

 

[500e]

We have a industrial building Co in the group, last pour was 23 x6 cube in the day.
The floor we caught was a friends, "we were to expensive" we also suggested a 2mtr wall blocks on edge with no piers was not a good idea also

 

[nodeward]

how you get the mesh 25mm into the slab? cant visualise what you mean, how does the mesh get suspended so it doesnt just sit on the floor ?

 

[rtbcomp]

how you get the mesh 25mm into the slab? cant visualise what you mean, how does the mesh get suspended so it doesnt just sit on the floor ?

Stand it on small stones.

 

[normspanners]

we did the yard about 1.5 acres at the scrap yd 25yrs ago with 8" we knock out the mix roughly then laid the rebar mesh on top and then 'walked' it in, then tamped, with a power tamp, not an exact sience but it worked and a lot quicker/ easier to walk,while pouring, with no rebar .
but that was for a yard not a garage floor! Speed was the thing with 4 trucks running crete
at us!

 

[Pete.]

I've seen people walk the mesh in too. Bit of a cowboy method as you have no control over where it ends up but it does the job.

I have 3" of concrete in my workshop and no mesh, and right now there is a 1.5ton lathe sitting on four casters on it quite comfortably along with my other lathe, milling machine, bikes and mountain of other gear. No cracks so far and I just put the one joint down the middle for expansion. For a shed or workshop rebar isn't really necessary. If you're driving vehicles in and out it's a different matter.

 

[normspanners]

As long as you have the same slump each time you get to know the feel of it

 

[Pete.]

I guess on the ground and fully supported it doesn't make so much of a difference.

I don't know so much about putting concrete in, but I'm an expert at taking it apart and the difference between a well-cast slab and a monkey-job is night and day. I've had whole slabs come adrift from a building before and nearly been killed several times from someone else's poor practices way back when. Stuff from the '60s and 70's is particularly bad, but then that was before they had clerk of the works and CDM regulations.

 

[armalites]

They can put synthetic strands into the mix at source now.

 

[nodeward]

cheers guys, im starting to think about putting it straight on the concrete, maybe give it a coat of paint. saves on wood for the floor as well!

 

[pidgeon chit welder]

If your on your own doing it fairly dry is reasonably easy .
You could use paving slabs on damp lean mortar mix on top of a wpm which is on top of three or four inches of dead level dryish lean mix and run a small vibrating plate over the slabs . You can then use self gluing studding to anchor the shed walls to the slabbed base .
Perhaps even use slabs on the inside or a 12 " thick cast in situ outer wall of concrete so you have an internal raised floor an inch or so above the ground to stop rainwater coming in .

Mortar the joints later and seal the shed base outer edges with a very long life flexible silicone when its dry .

Whatever you do don't forget to run a decent power cable / water supply in ducts inside the shed area , so you don't end up tearing the OH cables out occasionally

 

[nodeward]

i was planning on using a solid concrete base as there is already a small one there (its brand new) and i was just going to add to it i.e lay another slab of concrete next to it.

self glueing studding sound good though.......never heard of it before, where can you get that from???

 

[Epicyclic]

For my 25' x 13' garage at the old place we put a really good hardcore base in, well compacted, and put 4" of concrete on top, no reinforcement, and its been fine for general hobby use working on Landy's. We used ready-mix concrete as it went down in one and gives a consistent mix. Walls were brick with footings up to a pitch roof built on the base.
Did the build in '85 and its all still fine.