Hoist - what?!

Fabricating the studs and spacers is a lot of work, and securing the base plate with chemical anchors is easier and looks exactly the same. There's no need to join the hold-downs with the slab reo with appropriate concrete mixes with these loads as there is sufficient bond via the concrete. As long as you don't get too near the edge it will work.
 
Why I queried it before, is that IMO, the above specs are not too onerous at all - if you are building a new shed.
The standard concrete depth in any workshop/shed would be 100mm. OK, another 100mm of roadbase compacted underneath it, not too unusual. The reinforcing mesh would not normally be included in a domestic shed, but something the concreters do every day, no problem.
The 200mm depth only comes into it for a repair or inlay job.

The reinforcing mesh adds a lot to the strength. When I had my backyard domestic shed/garage built about 30 years ago, I had a friend in a concrete family business - he recommended me (at small extra expense) to get 75mm reinforced instead of 100mm non-reinforced. It was a 6.0 x 9.0 metre floor in a colorbond shed. 2 reasons, it was just as strong or stronger, but mainly with reinforcement mesh the concrete would not crack, so avoided the necessity to put the usual grooves every 3 metres or so. It has a very smooth surface, I think that's what happens when they use steel trowel finish. It still looks good.

Following the above specs, and being a conservative fellow, if I was putting in a hoist I would probably be asking for a 150mm reinforced floor over a 100mm compacted roadbase underlay - and only in the end section of my shed where the hoist would go - ie, 3.0 x 6.0 metres.

I note the mesh is laid 30mm below the surface. I think this would be to get the dynabolts down into the reinforced area, not just the top surface.

Plenty of information in this thread for Schlitz to make some conclusions, I reckon.

Cheers.
You seem to suggest that reinforcing mesh is optional.

Not in my world.
Every bit of concrete bigger than a stepping stone gets mesh.
Even the 3m by 2m duckpond got mesh.
For a heavy duty workshop floor, I would suggest that 150mm with F82 mesh, over a compacted base is plenty. Put plastic sheet under the concrete.
Yes, put the mesh up on chairs, overlap and tie the sheets. Put 12mm rebar around the edge. Even better is a perimeter trench with trench mesh.

Some prefer a very smooth surface, even go to the expense of epoxy surface.
However in my experience any fluid drips become a serious slip hazard.
I prefer a steel trowel finish, but not too fine, as it's good to have grip when pushing stuff around or manoeuvring heavy stuff.

Including threaded rods in the slab might seem smart, but it really gets in the way of a nice uniform finish, and makes a mess if you get it wrong....... which is often, cos someone reads the drawing wrongly, or reads the tape wrongly, or bumps the threads during the pour.
Don't think..... naa not me...... I've seen the experts get it seriously wrong.

These days, drilled anchoring systems are just as strong, and quicker than threaded starters.
I have used hundreds of anchor screws of various sizes over the years. 6mm up to 16mm. They are amazingly easy and amazingly strong.
One time we had to cut and remove 8 pieces of 150mm slab, about 1.2m square, so we could lower the floor by 100mm to fit a floor level pallet wrapper and weighing station.
After cutting the pieces with a concrete saw, I drilled a hole in the centre of each piece, and using just one 16mm by 100mm anchor screw lifted each piece out with a chain and a fork lift. That 1 screw was screwed into each piece, in turn to lift them out, then again into each one again, in the same hole, too lift them back in after lowering the base.
So the screw was used 16 times, and each hole in the concrete had been screwed into twice, without losing grip.
Why would you use anything else?
 
I concur.

Both on the reinforcing (I have found every house I lived in Oz has the slab cracked, mainly at the corners but I have also found cracks going across the entire slab) and the chemset anchors. I don't know what they use in that paste but it is as tough if not tougher than the surrounding concrete. Chernobyl's probably got nothing on the factory where they make that thing for pollution. Use some high tensile steel anchors and you won't have any problems. I actually made an adaptor plate for my engine stand to mount Renault 807 and Peugeot DFZ engines sideways using a steel plate and many of these anchors from Bunnings. I trust it enough to do up flywheel bolts with the engines on the stand. The ground moves too much here with the change from wet to dry season to trust a large thin concrete slab.

I want it polished because I want to be able to vacuum/sweep/wash/clean away metal swarf from my machines. If you've ever seen the chips generated by side milling steel you know what I mean. Those fuckers are nearly impossible to see spiral filaments of metal and they will stay put until they get you if the floor has the tiniest of imperfections. I also found they can attach themselves to the soles of your shoes and as you walk you work them in deeper and deeper until they come out the other way and go in your foot. No more, thank you very much.
 
Ahhh..... machining swarf.
I had my machines ( lathes, mill, radial arm drill and welding) in the same space as my general workshop..... until I got tired of trying to keep the swarf out of delicate jobs. So now the machine area is completely separate.
 
Reinforcement, whether mesh or bar, is NOT optional. It would also be a good idea to use a membrane under the slab.

The cracking Buttercup observes comes from shrinkage, and is difficult to completely avoid without tensioning which puts the slab in compression,, but it can be minimised. Control of slump is important, you do not want excess water.

I don't really think polishing is what's wanted - this involves grinding off the surface, and is very expensive and requires a special brew for best results. Trowelling brings cement paste to the surface and can give a very smooth even shiny finish. If that isn't sufficient to keep swarf at bay, coat the slab. At the cheap end is chlorinated rubber which is softish. At the optimum end is hard two pack epoxy. Either can be replaced if worn.

Proper wet curing is essential for a hard surface. The concrete strength you purchase takes 28 days, though most develops in a week.

Properly fitted chemical anchors are more than sufficient for normal loads. Grip exceeds the concrete strength.
 
I agree, seasink.

Except for coating. I have had painted concrete and while it's very good and does everything you want normally, it is not good enough for the problem I have. The other problem is that I use a lot of chemicals (machining coolants) that would most likely destroy any coating in short order.

As for smoothness, I have just had another slab poured in the garage and that is very smooth like you say (the bloke did a great job trowelling it) but not good enough for problem free cleaning of said swarf. I know polishing means grinding the top surface and I know is expensive but I have to do it.

I haven't noticed any shrinkage cracking in it yet, but it's only one week old and it's not that big. We'll see.

I plan to have quite a few anchor bolts to fix my machines in place and plan to go chemical because I am very happy with these (I have already put a few in the walls in the garage for shelving).

Buttercup, I plan to partition off the machines from the rest because I am sick and tired of the mess going everywhere especially from the milling machine. The late is not that bad but milling aluminium especially is a disgusting job. I wish I could have some sort of chip evacuation in place with a vacuum cleaner rigged up somehow but my milling machine is so small I just don't have the room for it under the head.

What membrane are you talking about? The plastic sheet?

My thoughts are to have a bed of sand, rubble for drainage on top and then a plastic sheet. I also plan to have a drainage channel installed around it so runoff will go around rather than through.
 
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I agree, seasink.

Except for coating. I have had painted concrete and while it's very good and does everything you want normally, it is not good enough for the problem I have. The other problem is that I use a lot of chemicals (machining coolants) that would most likely destroy any coating in short order.

As for smoothness, I have just had another slab poured in the garage and that is very smooth like you say (the bloke did a great job trowelling it) but not good enough for problem free cleaning of said swarf. I know polishing means grinding the top surface and I know is expensive but I have to do it.

I haven't noticed any shrinkage cracking in it yet, but it's only one week old and it's not that big. We'll see.

I plan to have quite a few anchor bolts to fix my machines in place and plan to go chemical because I am very happy with these (I have already put a few in the walls in the garage for shelving).

Buttercup, I plan to partition off the machines from the rest because I am sick and tired of the mess going everywhere especially from the milling machine. The late is not that bad but milling aluminium especially is a disgusting job. I wish I could have some sort of chip evacuation in place with a vacuum cleaner rigged up somehow but my milling machine is so small I just don't have the room for it under the head.

What membrane are you talking about? The plastic sheet?

My thoughts are to have a bed of sand, rubble for drainage on top and then a plastic sheet. I also plan to have a drainage channel installed around it so runoff will go around rather than through.
Builders plastic off the roll, made for going under concrete.
Any builders supplies, even Bunnings!
 
......with firm support (not unconsolidated hardcore) so the chairs don't pierce it. Concretors walk on the reo.

Ground concrete needs to be placed extremely flat. Get a long straight edge to be sure during screeding. Sealing is still required, and there are several types.
 
I agree, seasink.

Except for coating. I have had painted concrete and while it's very good and does everything you want normally, it is not good enough for the problem I have. The other problem is that I use a lot of chemicals (machining coolants) that would most likely destroy any coating in short order.

As for smoothness, I have just had another slab poured in the garage and that is very smooth like you say (the bloke did a great job trowelling it) but not good enough for problem free cleaning of said swarf. I know polishing means grinding the top surface and I know is expensive but I have to do it.

I haven't noticed any shrinkage cracking in it yet, but it's only one week old and it's not that big. We'll see.

I plan to have quite a few anchor bolts to fix my machines in place and plan to go chemical because I am very happy with these (I have already put a few in the walls in the garage for shelving).

Buttercup, I plan to partition off the machines from the rest because I am sick and tired of the mess going everywhere especially from the milling machine. The late is not that bad but milling aluminium especially is a disgusting job. I wish I could have some sort of chip evacuation in place with a vacuum cleaner rigged up somehow but my milling machine is so small I just don't have the room for it under the head.

What membrane are you talking about? The plastic sheet?

My thoughts are to have a bed of sand, rubble for drainage on top and then a plastic sheet. I also plan to have a drainage channel installed around it so runoff will go around rather than through.

water flow takes a lot of thought. I'm going to run that plastic drainage channel (you can clip the top out of ) through the shed when/if I ever finish the leanto .... and concrete the floor. if you have lived where you are for a while, you will already know where the run-off wants to flow when its wet (in my case, down the side of the existing shed where I'm extending it).
 
Coating covers more than paints. Perhaps you should look into trowelled epoxy. Machine shops are finished in this, or less expensive and more common, a multi-layered epoxy coating.
 
Coating covers more than paints. Perhaps you should look into trowelled epoxy. Machine shops are finished in this, or less expensive and more common, a multi-layered epoxy coating.
I've had 6" of storm water through my shed twice in 35 years, a plastic drain channel would not cope with that.
Both times they were freak storms, but unfortunately they say such events will be more frequent.
I think some earthworks are needed.
 
Coating covers more than paints. Perhaps you should look into trowelled epoxy. Machine shops are finished in this, or less expensive and more common, a multi-layered epoxy coating.
I've got an epoxy coating in mine with some sand thrown it. Pretty good anti slip, and LHM/Coolant/Oil wipe off. Thinners is a bit more problematic though :)
 
I've had 6" of storm water through my shed twice in 35 years, a plastic drain channel would not cope with that.
Both times they were freak storms, but unfortunately they say such events will be more frequent.
I think some earthworks are needed.

storm drain would be cheaper, how do you keep it clear though ? We don't get the "weather events" here that QLD does. How wet it is now, is pretty much wet it gets before draining away..... mind you ... it is WET!
 
There's a reason house slabs finish above ground level all round. Shed slabs should too. You can ramp the drive up at the shed entrance, so long as it is at grade a bit further back..
 
There's a reason house slabs finish above ground level all round. Shed slabs should too. You can ramp the drive up at the shed entrance, so long as it is at grade a bit further back..
Sometimes it's not as easy as that.
My shed is near to my boundary, and the ground over the boundary slopes up for quite a distance.
Luckily I have access to that land and can do a bit of reshaping, if I get my hands on a suitable machine.
 
I don't know the technical requirements for hoist but this MCM video may shed some light... ( They mention 150mm slab requirements)
MCM shed tour

I also watch a lot of m539 (BMW dude) and he uses a self supporting 4 poster that looks like more than enough for the home workshop.
 
For drainage I plan to use the black plastic drainage channel from Bunnos with the metal grated top, all around the slab, should cope with normal rain events. About 140mm wide, 100mm deep. It will be open downstream and run into the street with no obstructions, about 10m away. The land has a gentle natural slope so it's easy to know where the water will go. I plan the shed to be about half way up (say about 1m level difference to the lowest drainage point and about .5m below the highest point in the plot) and above the highest local point so water ingress shouldn't be a problem. I also plan to water seal it all the way around the walls and the door is on the downslope face so should be okay.

Seasink, I am sure you know what you talk about but this is really difficult for me to chase up here (by that I mean investigate concrete companies if they can do it, what is it exactly they actually do, what materials they use and so on). It's a lot easier to just have the concrete polished after it's poured and be done with it.

Oh, and I plan the slab to stand proud of the surrounding ground by at least 10cm all the way around.
 
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