Rellie,
Do the slab, it is not hard just do some prep and make sure you have everything right before you pour.
Make it slightly oversize - say 20mm more than the outside dimension of your shed. set your level you want the top of slab to be by driving in a flat topped bit of timber in the centre of your slab area - should be slightly above ground level so you don't get water issues. All levels should then be worked off that top. As above a clear hose with water in it is a very good level - the egyptions used it on the pyramids!!
Dig down so you have min 75mm depth. Install timber formwork, making sure you have min 4 stakes on the outside of each holding in place - wet concrete is heavy and moves formwork easily. Make sure the top edges of your formwork are straight and dead level as this will govern how level your slab is.
You will have to get some reo mesh to hold the slab together. (concrete is crap in tension and all concrete cracks - yes all concrete cracks) F62 is pretty standard. (For those wondering on the labelling convention the 62 means 6mm bar at 200mm centres. Any overlaps of mesh should be at least 200mm. Reo should have a minimum of 50mm cover from any edge/surface of the slab. Plastic bar chairs to achieve this can be bought from hardware shops cheaply.
If it is a hot day or the soil is very dry you should wet the soil and reo before placing the concrete.
Concrete should be minimum 20mpa. And remember adding water is a no no. Even adding water to surface to help work a finish will reduce it's strength. If it seems too dry mix in a squirt of dishwashing detergent. This works wonders. Use a shovel or stick etc to poke and prod the concrete into place and ensure no voids in the concrete, especially along the edges.
Also make sure you have a screed and finishing floats as a minimum. The screed can be a piece of timber, so long as it is long and flat and can be run back and forth along the tops of your formwork to level the slab surface. If you haven't seen it done you start at one edge and whilst moving the screed back and forth sideways you pull it toward you pulling excess concrete as you come.
Finish with a trowel and work the surface to bring a smooth paste to the top. But don't work it too much. If you have an edging tool you should finish off by rounding the edges. Lightly running a broom over the finished surface will give a non slip surface if that is important to you. Don't touch the concrete once it starts to set, this will also weaken it.
Once set try to keep the slab wet for 7 days to gain strength. A dripping sprinker or hose can achieve this or cover it in black plastic. Watering a couple of times a day and letting it dry out in between is often worse than not watering it at all.
Leave the formwork for a few days and be carefull removing it - it can take chunks of concrete with it, especially if a bit rough.
EDIT: important tip for getting your slab square. Measure the diagonals. if they are Equal then your formwork is square.
Paradox,
although I'm not planning to pour concrete any time soon - I appreciate the time you have taken to outline the method/approach... once again I have learnt something new cruising through Seabreeze...
Seriously , if you want a concrete floor in your shed , call me I would be happy to help .Weekends only , no fee ,no charge at all , ohh ,,,maybe 2 coronas after work is done .
That looks fricken ace PR.
If it was me I'd pat myself on the back - buy a six pack and walk around the backyard, while drinking beer, patting myself on the back until the beer is all gone and I'm tired.
In the morning I'd ask my wife for a root to see the dawn in.
Given the size of that area i would not be able to resist incorporating the 2 existing fences into a shed,rather thanbuy something to fit in the space. you only need 2 more walls ,one with a door, and some sheets for the roof. go high for storage and headroom.
if you were in kalgoorlie , you could come raid my offcut pile
just joshing buddy , nothing better than the feeling of a completed backyard project and the beer that follows ......nice work!
No worries, just need a bit of warning when
Meanwhile , fill your wheelbarow with sand and practice pushing it up and down the driveway a few times a day , this will build confidence on the day
P.R
you wanted tips
My biggest one - seal the bugger. No matter how level the slab is, water will get in somewhere and it will piss you orf not being able to put stuff on the floor.
(1) afetr all is finished, lift it up and sit it on 10mm dowels, then squirt silicone sealant under it all round.
Then drop it, and seal again with a bead all the way around the base.
(2) seal the bottom U-channel in the corners with silicone
(3) use tin snips to cut a vee every 30cm or so in the outside edge of the bottom U-channel so it drains quicker
If your going to do a concrete slab ,before you poor it make sure you set up some 25mm orange conduit with a bend so the power cable to the shed can come up from underground through the floor on the inside of the shed wall. Works out heaps neater than having conduit strapped to the fence
If you need some concrete pm me.
The Westrac development up the road has over ordered +20 cubes in the last five days!
We may have to stick a fair bit of retardant in it to get it to you and you pay the fuel!
So what does pre-mix cost you ? Say 25MPa for comparison
Had any quotes lately ?
$660 / m3 in Tom Price.
Maybe $270 / m3 in Perth at the moment ??
$ 180 in NSW
^ I cart it so no real idea what it costs to buy. Sells at roughly $300 a cube on the bill but you know how it goes, cheaper as the volume increases. Figures that the price at Tom's place would be a lot dearer owing to transport, we caring drivers do not come cheap you know.
What $/liter diesel up that way?
Just out of interest, a bit of friendly building professional advice when measuring anything, whether it is mesh, timber , wall cladding etc do a check measure ,if I had a dollar for the amount of times that either me personally or other tradespeople have cut material 100mm short I would be rich, it's always that amount 100 mm it's sort of the Bermuda triangle of measurements in the building industry other than that everything else is a breeze
3mtrs by 3mtrs by .1 = 0.9cubic mtrs , rule of thumb , always order 0.2 extra just incase, so this project is for a GARDEN shed ,so an 85 mm floor will be MORE than suffice , ( there will be some left over )so order 1 cubic mtr cost aprox $280 - $ 320 , ooohhh plus 2 CORONAS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Strewth $300
I'd rent a cement mixer for half a day, you'd have it mixed and poured in 2hrs ish
Maybe $100 for rent and product
look around and get a concreter that works for one of the big builders. They have left over concrete from housing pours and will do you a deal. Last two I have had done they ask you to dig the hole and put down the form work. They do the pour its over in about 30 mins and is cheap as chips.
You blokes are all dead set legends. I cannot believe how much goodness is in this thread.
Thanks all. Looks like I'm a shifting stuff and digging LOL
