Concrete shed floor

[mendiplogs]

I'm a builder/ground worker. My input is.

Go 6" , Will be there forever and will be stronger with an amateur laying it.

Don't bother with premix, knock it up yourself. Will be cheaper and you can have a day at getting it right not a mad hour.

Lay a strip along the back wall level and tamped. Lay a metre or so strip down each side. Tamped and level. Fill the middle of this bit in, learn to lay it about right with the back of a shovel and then Tamp off the side strips as you go.

Lay another strip down each side and continue as above. Gives you plenty of time to lay it right and have the odd tea break as your going. Don't knock it up too wet and it will be easy.

 

HI MUTTLEY thats the way mate my dad been in the trade all his life and hes 78 years young and his dad before and your right mate :thumbup1:your better off mix it your self the lorry will only wait 30mins so it will be a night mere if you do not no what your up mix it your self mate thanks jon

[muttley9050]

I was taught in my apprenticeship that as a rule domestic concrete 4" no mesh, commercial 6" with mesh.

Anything a tractor or lorry is likely to be regularly driving on should be 6" reinforced in my mind. Yes it may be ok if you leave the mesh out, or lay it thin, but if it ain't your going to be gutted.

Edited October 27, 2013 by muttley9050

[difflock]

Having seen "professionaly" laid concrete (an expensive job under the supervision of a firm of architects) with TWO layers of mesh in failing inside of 10 years, simply because it was laid like slurry, with the mesh tramped in from above. (and witnessed by myself)

I will reserve judgement.

And having seen the brother, with great difficulty lifting 3" thick of uncracked shovel mixed concrete from about 50 or 60 years ago (and the cement content would have been minimal) from a heavily trafficed (incl del trucks of all sorts) farm street.

I will again reserve judgement.

Having said that I somewhat reluctantly agreed to our builder reinforcing the subfloor concrete in the house we built in 1995, but building in poor ground conditions, with floors poured in-situ on top of existing clay that would shrink when dry after many years of being covered by the floors/surrounded by cavity walls.

cheers

marcus

[gensetsteve]

Perhaps we should have a show us your concrete thread. People cant understand why I get excited about a bit of concrete but the difference it makes to your working day is massive no more sludging about in mud and you can sweep up.

[difflock]

Just recalled another snippet, the deeper the pour, the easier it is worked, plus the standard full 6 to 8m3 load covers less area, therefore less finishing time per full load.

PS

A very good University friend who is now a Senior Physio turned up one day while me an the two brothers were waiting for the next truck load to arrive.

Gillian rather neatly summed us up as,

"3 cripples waiting for more concrete"

She warnt wrong!!

[Howard R]

As mentioned above don't forget a damp proof membrane (DPM) down and make sure that there are no sharp stones underneath to puncture it whilst laying the concrete.

 

A top layer of mesh, 50mm down from the surface, helps to hold the concrete together and reduce the cracking.

 

Don't bother with a bottom layer of mesh.

 

There is so great advice on different ways to lay it above

[Dean Lofthouse]

I just played safe on my drive, and poured five full wagon loads at 9" thick with reinforcing mesh three inch up off the floor. You never know when someone might turn up in a challenger tank to visit you, always be prepared is my motto

[agg221]

Having only done concrete once I have very little to add, but a couple of things that may be of use.

 

If you are putting expansion joints in around the edges, we used Korpak which is like MDF soaked in bitumen. Comes in an 8'x4' sheet in various thicknesses (we used 25mm) and easy to cut to shape - in your case probably 6" wide strips.

 

Before we put the plastic membrane down, we blinded out over the base with sand - not very thick but enough to stop anything poking through the membrane. I don't think it makes a lot of difference if you use sharp or soft - we scrounged up every last bucketful of sand lying round the place in the end as we were a bit short.

 

Ours was the structural slab to the extension, so had low edge walls at the time, hence no edge boards to tamp off. We marked up heights on the wall (actually on the membrane) and filled to that, then tamped down with an edge board. I like James' technique of laying in strips, but not being aware of that we more just went for it and it turned out fine. Area was about 6m x 4m, hand mixed in a Screwfix electric mixer, by one person in about 6hrs working time.

 

Alec

[Dean Lofthouse]

I also hired one of these, you get the concrete somewhere near level then go over it with this, it vibrates the air out and shows up any hollows, then just shovel a bit extra into the hollows.

 

I tamped it crossways, then tamped it longways and it made it dead level very easy with no effort

 

http://belle-group.co.uk/index.php?p=products&id=283

[NI Tree]

concrete fails mainly were 2 slabs meet (and edges) as you are spreeding a load over a smaller area, therefore put your sub base under greater load. so for this reason you want to tie the slabs together but still allow expansion and contraction and if you are ending the slab in to a gravel yard make it a lot thicker and reinforce it at this point