Concrete shed floor

[ballibeg]

Looking at the jobs here mine seems tiny! Still it's my first concrete job, hampered by lack off any knowledge or experience!

 

Floor is 6m x 4m. Needs to hold the tractor up on stands and also be smooth for kids uses. Planning on 5 inch depth and unsure if needs rebar. Plan to just fill would leave me no boards to use to level or could I just fill and float? Added complication can't get concrete truck closer than .5 mile away so need to bring in by dumper I guess. Also thinking what can I set in concrete for secure anchors.

 

 

As I'm a beginner I'm asking for your top tips please!

 

Dave

[Pltreesurgery]

I would go 6 inches and use re bar, as it's outside I would give it a brush finish as opposed to smooth, bit more grip when it's icy, put a level mark on the wall and transfer it to the other walls if your not using boards , if it's wet enough it will self level a lot if you use a vibrating poker, but to wet isn't always good, IMO

Hope it helps

 

 

 

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[LGP Eddie]

Always a bit more awkward when there are walls surrounding the pour with no shutters to tamp off.

The way I'd normally tackle something like this is with a laser level and make up a staff from a square of 1/4 ply and a 2x2 upright so it actually floats on top of the concrete.

It just means you can get your level anywhere you like and keep working your way out.

I'm lucky to have a single grade laser so can actually put a fall from back to front if required?

 

However easy options for you are?

 

Agilia Concrete, simply brilliant but more expensive? In such an application you would simply tip it in and go over it with a hand tamp job done!

It will truly self level and hey presto next morning the finish will be approaching a powerfloat finish?

It is such a labour saving method it's untrue (you can easily do that on your own), and I've seen some stunning results from it.

 

You could put boards down each side, but obviously these are a nightmare to tamp off being so narrow, and you don't really want a couple of inches of board down each side?

The solution I have used with great success is to actually fix some 2x2 angle iron down the walls each side at the desired height.

This is easy to tamp off (you can even set a fall to the front) and will make no difference to the integrity of the floor at the edges.

 

I would suggest a brush finish if you can too? An easy float after you have tamped and then install the brush onto it when it's good and ready ready will have that done in seconds with no hassle plus not expensive to hire.

If you are happy with the easy float finish, and you'll amaze yourself how easy it is, you can just leave it and forget brushing anyway.

 

I would suggest going with 6" unless you are prepared to spend the time to ensure your sub base is absolutely spot on to achieve a true 5", and the 6" will more likely give you 4" to 7" here and there?

I absolutely detest fibres, and in my opinion you can't beat a layer of mesh.

It will be simple enough here to install in sections as you bring the Dumper in and tip onto it.

I would suggest some plastic underneath if possible, allow for the fact the concrete isn't going to like the dumper trip much and will separate out somewhat, lastly get plenty of assistance if you can.

 

Best of luck.

 

Eddie.

[openspaceman]

I would go 6 inches and use re bar, as it's outside I would give it a brush finish as opposed to smooth, bit more grip when it's icy, put a level mark on the wall and transfer it to the other walls if your not using boards , if it's wet enough it will self level a lot if you use a vibrating poker, but to wet isn't always good, IMO

Hope it helps

 

I agree and look to puting expansion material against the walls. I imagine there's no damp course in the building?

[ballibeg]

Thanks guys. Will take on board and let you know how I get on.

 

Dave

[difflock]

From a final year failed Civil Engineer

(i) Excess water is the enemy of all concrete, in the absence of fluidizing agents it should be stiff (hence the "slump" test)

(ii) Absolutly no need for rebar

(iii) 4 or 5" thick is plenty over that small span/area. Assuming solid beneath and the hardcore is well vibrated with a heavy plate.

Volume for 4"=100mm deep

6*4=24m2*.100m(100mm) = 2.4m3 (or 3.6m3 for 6"/150mm)

Could you not get a "Mini-mix" truck nearer hand?, I think they usually max out at 3.0m3.

Or consider a pan mixer behind the tractor and mix your own.

Or buy dry mix and simply add water at the site, putting it through a pan mixer.

5 miles on a rough track is going to vibrate the water out of a wetish mix.

Needs to be semi-dry, then wetted down and remixed at the site.

Definately put plastic below, the primary reason is to prevent water escaping from the mix down into the hardcore below, when being vibrated/tamped.

cheers

marcus

PS

Rule of thumb

Concrete needs 1 month to cure (28 day strength), so give it time before putting the tractor up on stands or jacking on.

Edited October 26, 2013 by difflock

[gensetsteve]

From a final year failed Civil Engineer

(i) Excess water is the enemy of all concrete, in the absence of fluidizing agents it should be stiff (hence the "slump" test)

(ii) Absolutly no need for rebar

(iii) 4 or 5" thick is plenty over that small span/area. Assuming solid beneath and the hardcore is well vibrated with a heavy plate.

Volume for 4"=100mm deep

6*4=24m2*.100m(100mm) = 2.4m3 (or 3.6m3 for 6"/150mm)

Could you not get a "Mini-mix" truck nearer hand?, I think they usually max out at 3.0m3.

Or consider a pan mixer behind the tractor and mix your own.

Or buy dry mix and simply add water at the site, putting it through a pan mixer.

5 miles on a rough track is going to vibrate the water out of a wetish mix.

Needs to be semi-dry, then wetted down and remixed at the site.

Definately put plastic below, the primary reason is to prevent water escaping from the mix down into the hardcore below, when being vibrated/tamped.

cheers

marcus

PS

Rule of thumb

Concrete needs 1 month to cure (28 day strength), so give it time before putting the tractor up on stands or jacking on.

 

Dead handy a resident concrete engineer It occured to me getting 6 metres of concrete 1/5 mile down a track is going to take some time and they only wait 1/2 hour also it will be going hard at the end. Can you borrow one of those big diesel site mixers and do it all onsite. Another idea would be hot lay tarmac and put down wood when jacking things up.

[gensetsteve]

From a final year failed Civil Engineer

(i) Excess water is the enemy of all concrete, in the absence of fluidizing agents it should be stiff (hence the "slump" test)

(ii) Absolutly no need for rebar

(iii) 4 or 5" thick is plenty over that small span/area. Assuming solid beneath and the hardcore is well vibrated with a heavy plate.

Volume for 4"=100mm deep

6*4=24m2*.100m(100mm) = 2.4m3 (or 3.6m3 for 6"/150mm)

Could you not get a "Mini-mix" truck nearer hand?, I think they usually max out at 3.0m3.

Or consider a pan mixer behind the tractor and mix your own.

Or buy dry mix and simply add water at the site, putting it through a pan mixer.

5 miles on a rough track is going to vibrate the water out of a wetish mix.

Needs to be semi-dry, then wetted down and remixed at the site.

Definately put plastic below, the primary reason is to prevent water escaping from the mix down into the hardcore below, when being vibrated/tamped.

cheers

marcus

PS

Rule of thumb

Concrete needs 1 month to cure (28 day strength), so give it time before putting the tractor up on stands or jacking on.

 

If you had a bobcat and big jcb running over a 6m x 6m pad what thickness would you use and would you reinforce it. I never thought about putting polythene down before I guess this would make it more workable for longer and give it more of a chance to self level.

[LGP Eddie]

My suggestion for Mesh is based on the images supplied and the simple fact there could be any amount off fill under that bit of sub base?

For the extra cost it'll be there forever.

 

4" would do the job and an accurate 5" would be very nice, but for someone who's not particularly experienced, then aiming for a 6" pour will allow plenty of tolerance.

 

I'd agree you'll be surprised just where you an get one of the smaller 4 wheel mixers, but 1/2 mile isn't the end of the world and just get a Volumetric mixer in?

He'll wait no problem, mix it as exactly as you like, conveyor it up into a dumper and you can judge the last bit pretty accurately with no waste.

 

Eddie.

[muttley9050]

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.

Edited October 26, 2013 by muttley9050