# Forum Home Renovation Concreting  How To Floor (Concrete) A 4m x 3m Shed?

## abrogard

I just put up a small Stratco flimsy garden shed. On four concrete footings at the corners. And I just poured a 'doorstep' under the door and anchored it in there. 
This is my first experience of concreting. 
I find that even with a concrete mixer you can't do much in a day - especially if you've got young kids to look after and can't DO a day's work - only an hour here and an hour there. 
So I was going to pour a slab 100mm thick. Now I see I'm going to have to do it in sections, because I won't be able to do it all at once.  
The experience with the 'doorstep' (about 1.2metre x .5 metre x 150 mm ), which took four concrete mixer loads, shows me that I'll probably only be able to do about that much at a time.   Maybe 1 metre square at a time might be something to aim at.  One metre inside the shed and 100mm outside, maybe slabs of say 1.1 metre square. 
(and it's bloody amazing how calcations of what concrete I'm going to need and how many mixer loads that'll be never seem to work out) 
Now I was going to lay plastic sheet down because working as a labourer on building sites years ago I saw that's the way they always do it. 
And I was going to put reo in the slab - F52 - was the number the local building supply people quoted at me. 
But now I see I'm going to have to cut the reo into little 1metre squares and I wonder how I can tie one slab into the next? I can't. So that gives me little more than paving slabs, right?   So maybe I don't need reo at all? 
And reading threads here I see lots of people suggesting you don't need plastic. 
And whatever the truth of that, no one seems to suggest putting plastic under a 'paver' you've poured.  Or is that because they don't expect you to pour pavers? They expect you to buy them and just lay them? 
So I'm all confused and I'm asking for intelligent experienced help. 
Given I've got no chance of doing anything but pour little by little, how should I do it? 
Should I put reo in? What reo?  Put in how? 
Should I put plastic underneath? 
Should there be some special treatment between each adjoing mini-slab? 
Or am I in a situation where you'd just kind of pour 'pavers' right there in place?  
What kind of pavers?  100mm thick? Or being just pavers now, not a slab, should they be much thinner? 50mm?  
regards, 
 ab  :Smilie:  
p.s.   Or should I stop asking for so much help and just do what seems right to me and learn from experience?  I'll tell you what, it seems right to me to use plastic, to pour 100mm 'pavers'  with something between them - thin ply maybe - and put some light reo in each 'paver'.  All on a bed of cracker dust slightly damped down to even things up a bit.

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## Ronaldo451

Welcome to the Forum.  
The 'right' thing to do will depend upon what you are going to use the shed for, how much trouble you are prepared to take and at what cost. 
The plastic will help stop damp seeping up through the slab, which will certainly help if you are going to be keeping tools and material on or near the floor - not much effort and not much cost so why not? 
Whether you need reo or not ? I would stick to 100mm thick slab/s, but if it is only a garden shed the reo may be optional. If it does crack how much of a drama is it going to be for you? (assuming it is a level site and is not going to drift off down the yard). If it is mainly cosmetic and that is not a worry you have answered your question.  
Keep an eye out for any construction work going on in your area. If you are in the right place at the right time with a box trailer you may be able to score some left over concete - they usually just dump any leftovers and are happy enough to give it to a punter if you have not made a nusiance of yourself.

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## BRADFORD

However you do it make sure you don't continue your floor under the walls to the outside, as rain running down the outside of the wall will run onto the concrete and under the wall into the shed.
This is a common mistake made by people erecting garden sheds. If you want concrete outsie put it say 25mm lower than inside and make sure the shed floor does not extend past the walls.
I think for a garden shed 100mm floor is overkill. If I were in your situation I would put mesh right through and just do it in whatever size slabs you can manage,(75mm thick) put a joint around each slab and the mesh will tie them all together. 
Hope you can make sense out of all that 
Regards Bradford

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## abrogard

Well I'm going to use it for storing my tools. From time to time if I can I'll work a bit in there, until I've got something built I can work in.   
How can I do it in mesh right through and in slabs at the same time?  To form up one slab I'll have to cut the mesh and it'll be hidden in that slab. The next slab will have to have its own mesh, right? Such small slabs. They'll need mesh? 
I want the floor to go outside the shed to catch the drips off the roof.  I've noticed that slabs around these parts seem to excavate the ground around themselves if the rainwater is allowed to fall straight down off the roof. 
So I'd planned to smooth the concrete on the outside to a slope downward and outward as it got near setting.  In fact I saw that suggestion (or instruction?) somewhere in something I googled. 
I meant to do it with the doorstep but I didn't.  Will it be easy enough to do or is there some problem with that idea? 
What is ' a joint around each slab ' ? Just a space? Or I need some thing in there? 
Thanks for your input, guys, it is appreciated.   :Smilie:

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## Pulse

premix delivered? If there is easy access then it is a no brainer!
Cheers
Pulse

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## piscean

> I want the floor to go outside the shed to catch the drips off the roof.  I've noticed that slabs around these parts seem to excavate the ground around themselves if the rainwater is allowed to fall straight down off the roof.

  you can still do that but as Bradford said, it's a good idea to do them at different heights so that the outside is lower than the floor inside the shed. we made this same mistake when we put up a garden shed and as soon as it rained the water would run in underneath which meant we couldnt leave anything near the walls.  Luckily we had done it in pavers so we pulled up the floor inside the shed and raised it up to make it higher than the base outside the shed so that when it rains the water stays on the outside.

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## abrogard

I think  you're right. I was thinking about it. It might be easier and better to form it up so's there's a 'ledge' outside the shed.  Easier than trying to work the concrete into a slope. I don't really know, never having done it. 
Premix can be delivered. The shed's accessible. I'll ask them if they can deliver it in through the shed door. And what the minimum load is.  
If you get premix I guess you've got to take the whole load?  And you've got to allow in your calculations to make sure you get enough. So you're almost certain to get some excess. So I'd need somewhere to put the possible excess. Like what? Dump it on the ruts in the driveway on the verge might be a good idea. 
Nobody's said outright about the small slabs and reo but Ronaldo seems to suggest I wouldn't need it.  
I still don't understand Brad's 'put a joint around each slab and the mesh will tie them together' .  
I guess readymix is the way to go. On that size I figure it'd cost about another $100 above what doing it myself would cost.  For the work saved and the speed of getting it done and the quality of one single completely meshed floor slab I guess it's like Pulse says, a 'no brainer'.  
It's quite obvious to me that anything bigger than this should be readymix. 
It's obvious to me that we should have poured the slab before putting up the shed - and it should have been readymix. 
So why I'm so stuck on doing it myself I don't know. I'm just a slow thinking fool I guess.   
Thanks for your input, guys.   :Smilie:

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## chipps

> I just put up a small Stratco flimsy garden shed. On four concrete footings at the corners. And I just poured a 'doorstep' under the door and anchored it in there.   *Might be easier to dismantle the shed, or unbolt & lift it aside, dig up the concrete & start from scratch.*  *Also, you may need a pump truck to get it into the shed.*  *The idea of a concrete truck waiting while you barrow on your own, would probably end up a big rush job, poor result & even doing yourself some damage (This stuff is heavy!!)* 
> 'pavers' with something between them - *thin ply* maybe - and put some light reo in each 'paver'.  *Timber & dirt aint a good mix*

  Good luck either way abrogard, your gunna build some new muscles  :Wink 1:

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## BRADFORD

As Chipps said it would be easier to dismantle the shed, boxup and pour the slab, then re erect the shed. If you use Readymix to pour the concrete the buy a couple o cartons of beer and get as any mates as you can around to give you a hand, however it is peferable that at least one of you knows what their doing otherwise it could be a disaster. This would be the best way to do the job.
If you go with the small slabs, put your mesh right through, then use 75mm wide timber, with slots cut in it to match the mesh, to box up each slab, (make sure the mesh stays about the middle of the slab). When finishing run the edng tool around the edge and when you do the next one the same you will have a joint between them but the mesh will continue right through. 
I'm not too good at explaining things in writing so I hope it makes sense 
Regards Bradford

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## abrogard

Thanks, Chipps. You've set me on the road.  
I'll do 'pavers' with light reo whatever that is - this 'F52' the builder's supply mob talked about, or the 'chicken wire' local guys talked about? 
I'll put thin ply between them.  All resting on plastic sheet. 
I'll take the slabs/pavers outside the shed and either work the concrete to slant it downwards as it's setting or take the trouble to build forms that'll make it lower.  How hard is it to work concrete like that? Wait till it's hard enough and then shave some off so it slants down? 
I can see it could perhaps be a no go - perhaps when it's hard enough to hold its shape well then scraping some off will cause you to catch lumps of gravel and hook them out of the mix leaving a big hole that the concrete is now too hard to fluidly smooth out. 
There was someplace I googled where they talked about doing it this way, though.  
I see now that the Hills Hoist is in the way.  So I couldn't get Readymix in there anyway. 
It'll be slow but I'll get there, no drama.  
regards, 
 ab  :Smilie:

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## abrogard

Thanks Brad. You were posting yours as I was posting mine.  You mean 75mm wide as in something like 19 x 75 ? Like the slab will be 75mm deep? 
I don't even know what an edging tool is. 
Then before I do the next slab put some thin ply in there (below the reo?) to make a joint ? 
You're right. It really would be easier to go backwards and start from scratch, but that's never going to happen, not in my world here. It's not an option. Everything just has to proceed as best it can. My world's littered with unfinished jobs. We're already using the shed, nowhere else to put stuff.  Because of that I'll put the reo half way and do the other half later and overlap and tie the reo. 
ab  :Smilie:

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## BRADFORD

Thats right 19 x75 would be ok. You set it up around your slab with the top edge level and at the finished height of your floor, when you screed off that you will have a level floor.
The edging tool you run around the edges of your slab to give it a nice finish. When finished , remove th 19 x 75 boxing,and use it to box up your next slab, Don;t put anything between the slabs just butt them up to each other. I don't think you will be able to slant the outside too easily while you are finishing, if you want to go that way cut an angle on your timber boxing where it extends outside then finish your concrete to that level, this will give you a slope to the outside. 
Bradford

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## Planned LScape

F52 will be fine for the shed slab @ 100mm thick. Better finish and stronger to do in 1 hit, it's only 1.2m of conc so if you have a decent barrow and a mate with one, you can get it in the area in 10 mins or so and get it screeded aad floated before it starts going off. Ask for a paving mix as it will give you more time to work it. 
Make sure you get your measurements right and if there is surrounding paving or concrete, raise the shed up a bit so water doesnt travel underneath the wall sheets. Otherwise you can concrete inside once installed.

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## Terrian

as Planned says, it is only 1.2m3 of concrete, 2 (decent) wheel barrows going and 10-15min later the truck is gone, leaving you with concrete to level.
if the concrete is about 75 - 80 slump you should have no problem getting it spread & leveled. 
if you leave the shed in place, put some marks on the walls 100mm up from the ground to help you keep your level. 
your measurements say 1.2m3, order 1.4m3, if you have any left over from the shed you can add a small slab at the doorway. 
BTW, a concrete edger looks like: http://hand-tools.hardwarestore.com/...er-221739.aspx

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## dazzler

Another option that is used in some green house applications is to purchase some brick pallets from a recycling place.   Level the site and put down some fine crushed rock, sit the pallets on it and level much like paving.   
Bolt them together through the sides then sheet over the top with some marine ply (get the seconds that are the top and bottom sheet of the pack) and then put your shed up on that.  No water problems, no laying concrete and uses recycled products. 
And its made of WOOD  :2thumbsup: , not polluting concrete.

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## abrogard

That's a good clue about the pallets. We might do that for a greenhouse, my wife has a flimsy plastic thing she calls a greenhouse and it needs improving. 
The shed is going to get the slab poured from the inside.  
I know it's crazy and I should move the shed off the footings, pour the slab and move it back. But I won't. I'll pour it piecemeal as best I can right where it is. 
Not only that but I'll be using the shed while I do it. All the stuff I've got in it (because we've got nowhere else to put it)  I've moved over to one side.  I'll pour the other side, then move the stuff and pour this side. 
I just don't know how I'm going to screed it when the shed wall stops the screed board from resting on top of the formwork. I guess just the solidity of the concrete will do it. 
And I don't know quite what i'm going to do about bevelling or sloping the outside edge of the slab so's the rainwater doesn't come inside. The surest way would be to form it up so's the outside 'lip' (or whatever you call it) is lower than the inside slab. But for some reason I don't like that as much as having the slab come straight out from under the walls and then slope down a little. 
But what I like might have to give way to what seems to be the best. 
Only 1.2 cm, I know.  But my mixer only takes 0.0515 cm at a time.  That's 23 mixer loads. 
I'll tell you what that is.  It is two of those white plastic buckets that I think they keep paint in  290mm across the top, 390 mmm high. Bit of a taper on them that I've ignored. 
I find each of those buckets takes five 4 litre ice cream containers of sand and gravel mix.  That's handy because I'm told to use cement in 1:5 with that mix. 
So that's one ice cream container of cement for one painter's bucket. 
The mixer only takes two of those loads and if it gets a bit sloppy it'll spit odd gobs out here and there.  
My trusty calculator tells me that it adds up to 0.0515 cm which is such a weird number that I can see why everyone talks in cubic feet for concrete mixers.  My same trusty calculator tells me that at 35.5 cu feet per cm  two cubic feet = 0.05634 cm. 
So my mixer, which I thought was quite large as home mixers go (and very, very ancient) doesn't even rate two cubic feet. 
So it is going to take some time. I can't be shovelling into the mixer while I'm barrowing and pouring concrete. 
There doesn't seem to be any real problem.  When I poured the doorstep it took three mixer loads ( I just don't remember too well, it might even have been four!) , which took some time because I'd never done it before, but I noticed the concrete was easily workable more than an hour after I'd finished. 
What are the time constraints on concrete work?  Just how long is it supposed to be before it 'goes off' ? 
And if I'm going to screed a slope into the concrete round the edges how long would I have to wait before the concrete is set enough to be able to work a slope on it? 
And having waited that long - how much time have I got to do that work before it is TOO hard to continue?? 
They're all dumb questions, aren't they? 
Well, I'm just a dumb guy.  You can tell by the mess I'm in and the way I'm going about this dumb job.  I've got at least two good mates (thousands of klicks away from here, unfortunately) that I know would have knocked this job over before breakfast.... 
I was badly brought up.... that's my excuse and I'm sticking to it....   :Smilie:

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## Terrian

> Not only that but I'll be using the shed while I do it. All the stuff I've got in it (because we've got nowhere else to put it)  I've moved over to one side.  I'll pour the other side, then move the stuff and pour this side.

  that will actualy be an easier job than if you were to do the whole floor in one hit.   

> I just don't know how I'm going to screed it when the shed wall stops the screed board from resting on top of the formwork. I guess just the solidity of the concrete will do it.

  you don't 'see-saw' the screed, you just sort of pull the screed through the concrete to get the level, hard for me to explain, you might find taping a spirit level to the screed helpful in keeping the screed reasonably level.   

> And I don't know quite what i'm going to do about bevelling or sloping the outside edge of the slab so's the rainwater doesn't come inside. The surest way would be to form it up so's the outside 'lip' (or whatever you call it) is lower than the inside slab. But for some reason I don't like that as much as having the slab come straight out from under the walls and then slope down a little.

  slightly angle the formwork down outside the door, use a trowel to start the down angle from just inside the doorway.   

> Only 1.2 cm, I know.  But my mixer only takes 0.0515 cm at a time.  That's 23 mixer loads.

  but your only going to 1/2 the shed at a time, so it is only 12 mixer loads. OK, now the bad news, you wont be using a full mixer load, maybe 2/3 of a mixer load each time.   

> I find each of those buckets takes five 4 litre ice cream containers of sand and gravel mix.  That's handy because I'm told to use cement in 1:5 with that mix.

  making concrete, 3 parts stone (14mm) 2 parts sand (concrete sand!), 1 part cement.   

> The mixer only takes two of those loads and if it gets a bit sloppy it'll spit odd gobs out here and there.

  add water slowly, give it plenty of mixing time between each add of water.   

> So my mixer, which I thought was quite large as home mixers go (and very, very ancient) doesn't even rate two cubic feet.

  I think mine is 2.2 cubic feet.   

> So it is going to take some time. I can't be shovelling into the mixer while I'm barrowing and pouring concrete.

  correct, *you shovel into buckets, pour bucket loads into mixer (to keep the mix consistent)* add water, while that is mixing you barrow previous load into shed and pour, when you get back to the mixer you see if any more water is needed. Fill up the buckets with stone/sand/cement, pour mixer load into barrow, empty buckets into mixer, add water, barrow to shed, etc etc etc.   

> What are the time constraints on concrete work?  Just how long is it supposed to be before it 'goes off' ?
> And if I'm going to screed a slope into the concrete round the edges how long would I have to wait before the concrete is set enough to be able to work a slope on it?
> And having waited that long - how much time have I got to do that work before it is TOO hard to continue??

  how long is a piece of string ?
it depends on too many things. 
Pour the slab as quickly as you can, keep an eye of the concrete as you are going, once you can put a hand mark, say 1/2" into the concrete and it holds the hand mark you can use an edger and trowel to shape the concrete, all you can do is keep the checking the concrete every 20 minutes or so (assuming it isin't a piping hot day, if it is a hot day just wait with the concrete!)   

> They're all dumb questions, aren't they?

  na, not dumb to be asking questions before you start the job.   

> Well, I'm just a dumb guy.  You can tell by the mess I'm in and the way I'm going about this dumb job.  I've got at least two good mates (thousands of klicks away from here, unfortunately) that I know would have knocked this job over before breakfast....

  mongrels, how heartless of them living so far away  :Smilie:    

> I was badly brought up.... that's my excuse and I'm sticking to it....

   :Smilie:

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## abrogard

Thanks, Terrian, for taking me seriously. 
You might be interested in this thread I found when I was looking for help with my tucker box freezer, I think it is hilarious, most especially reply number 8 of 17:  http://www.exploroz.com/Forum/Topic/...%2522%26pn%3D1   :Smilie:

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## Terrian

> Thanks, Terrian, for taking me seriously.

  thats the idea of the forum, help if you can.   

> You might be interested in this thread I found when I was looking for help with my tucker box freezer, I think it is hilarious, most especially reply number 8 of 17:  http://www.exploroz.com/Forum/Topic/...%2522%26pn%3D1

  shall have a look.

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## BanPC

Abrogard... 
If you are going to pour in a patchwork fashion it is possible to tie each "paver" with the mesh.  I am assuming you will have a couple of boards to form each section you are able to pour on any given day.  If you were to take a small hole saw and bore holes that will correspond with the mesh bar gap you then slide the mesh (which you cut a little bit bigger than the patch you are going to pour) through these holes and form the square you are about to pour, leaving the over sized mesh bars outside of your form board (only has to be 100mm or so).   
A bit of concrete will leak out through the holes but nothing that will cause you a concern.  Screed this section and finish off. 
When you remove your form boards there will be some exposed reo mesh stems... this is what you tie your next little piece of reo mesh onto... form the open sides with your holy {lol} boards and repeat. 
Doing this will "tie" each patch together with the mesh rather than a dry joint each time with no tie into the next area... basically the mesh tied together will give each section support and resist lifting like large tiles with any ground movement along the joints. 
When you pour outside past the shed wall it will create a small shelf.  If rom your post I think your intention is to trowel a slope downwards away from the shed wall to allow the water to run off,  please keep in mind that concrete is porous and moisture will eventually soak in in extended times of rain.  You would seriously need to think about coating the external concrete to waterproof it. 
Plastic underneath is a good idea in my humble opinion.   
.

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## abrogard

Thank you for your post. I really do appreciate the time you knowledgeable and done-it-before or done-it-all-my-life guys take to help out such guys as myself.  
I just thought I'd mention that. 
I'll be doing the reo thing you mention. I got similar advice earlier.  
It fits in with another thing I've found out about this madness of pouring your slab after you've built the shed: you can't get the reo in!  I'm going to have to slide the reo in under the walls and between the footings blocks, which means I'll have to cut it so's it'll fit in - and then it'll be shorter or not as wide, as it ought to be. And I'll have to add little bits all around to bring it up to size. 
So I've got some tie wire and I'll be tying all these extras on. How should I tie? Like is it okay to lay two bits of reo side by side and tie them like tying two pencils?  I assume it is, but I thought I ought to ask. 
'Resist lifting...'  - I think that might be quite important round here. There's many stone houses and they're all cracked. People tell me it's because of the ground. The ground seems to be a very fine dark sand, almost a silt I'd say, but I'm no geologist. 
I think extended periods of rain that'll soak the exterior 'shelf' enough to cause the slab inside the shed to be damp ( I guess that's the potential problem there?) would be greatly welcomed hereabouts....    
But I'll look at some exterior concrete waterproofing paint.  
But I suddenly become aware that maybe the best strategy is not to extend the slab outside  at all?    I'm thinking of doing it because I see so many sheds sitting on slabs on sloping ground (and what ground doesn't have some little slope somewhere?) that have all the soil eaten away by rain water from the roof around the slab, leaving it sitting up there high and dry,  and soil erosion occurring underneath it in that area. 
I'll be putting plastic underneath for sure. It's the way I saw them do it when I was a humble labourer on building sites and it is what seems recommended most often and it is what makes sense when we consider the fact (or what the internet seems to have taught me is a fact) that concrete continues to gain strength while ever it is kept moist. 
I'll even have plastic up the sides, inside the formwork and plastic on top for a week after pouring.   :Smilie:  
This is a tiny little operation but it's all new for me and it'll be the experience I have to draw on when we build our carport, which we plan to be about four times the footprint of the shed. That's why I'm taking it so seriously. 
But why pour after the shed is built?  Madness. Sheer madness.    :Smilie:  
p.s.  regarding what I saw the big-time experts doing on those multi-story building sites I worked on:  when I think about it I recall that it was only the ground slabs that they put plastic under.  Not the floor slabs for the higher levels.  They kept them damp on top, sprayed water and covered with plastic, but once the formwork was stripped from beneath the slab that was it - it was unprotected concrete. 
So what's all that mean? I dunno.   :Smilie:

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## BanPC

I am not sure how your shed roof is configured... however if the roof sheets just run outside the wall a short distance and stop I have in the past to prevent water hitting right near the wall used this method. 
Get a piece of PVC conduit or PVC plumbing pipe (bigger diameter is easier - about 90mm I used),  run a cut through one side.  The width of the blade should give you a slot if the roof prolfiles are to large make a second cut so the slot is just a pooftienth smaller than the profile - your trying to make like a C with enough tension to clamp onto the roof sheet,- now slide that slot along the end of the roof sheets the length of the shed wall.... to put a gradient on it at one end place a block on the top of the roof sheet jammed in to the inside top of the conduit.... then repeat at the other end in reverse using a thin peice so the water can pass around it.... underneath the low end get a large terracotta planter box full of rocks or dig a small drainage trench with agg pipe or rocks to dissipate the water off on the natural gradient.  You can do this both sides of the shed... sort of like a quick cheap gutter.   
.

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## abrogard

Got it. Good idea. Thank you. My roof is corrugated iron.  
  Your technique would apply to such sheeting? 
Yea or nay the principle is right: put some sort of gutter on. Yep. I'll do it. That'll help things. I'll still stick the slab out wide of the shed. I just like it like that.   :Smilie:

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## BanPC

Yes mate it will.... measure the height of the profile (height of the hills on the corrogation).. cut the slot in the pvc about 8mm less than that height making a C... the pvc will flex that 8mm but then clamp onto the sheeting.   
.

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## abrogard

Well I finished that job and never got back to the thread. 
 In the interim I see there's been more than a thousand people look at the thread.  So it is of interest. So I'll try to sum up what I did, what I learned.  
 Right:  It is a 4m x 3m steel shed already constructed on concrete footings. 
  I poured a 100mm slab using my own mixer and a barrow. 
 I poured it in six different pours. 
 Dug it out, tamped it down, laid plastic sheet, laid reo in there. Took the reo out under the walls and beyond by 200mm. 
 Formed it up 200mm wider all around. 
  Then I cut boards with slots for the reo and divided the inside into two side by side sections at the far end, covering a third of the length. 
  So I'd have six sections. 
  The sections about to be poured had reo chairs in them and chairs for a couple of feet on the reo protruding into the section nearer me and that was not yet to be poured but which the barrow would have to run over.  And I'd walk over. 
  And I laid planks to run the barrow over.  i.e. the whole thing was designed so's there'd be no movement of the reo on or off the chairs, just like a fair dink big job. 
  I'd barrow the concrete into a section and work it into the corners with the shovel and a length of timber.  I had a special piece of timber about 50mm square, 1.5m long for this.  
 Screeding it off I had nothing against the walls to rest the screed on to get the right height. But I found an advantage to the small sections, each about 1.5m x 1.3m. The screed board could rest across the two sides of the formwork for the section. So it was diagonal across it. This gave me a good start. 
  Then against the wall - the slab comes right up to the bottom of the wall - I just had to do it by eye. It wasn't so hard.  In the first place because the outside formwork was 200mm outside the wall the concrete flowed out under there and kinda levelled itself like water and I just had to add concrete until it came up to the wall. 
  The next day I'd strip the formwork from a section and pour the next section. Nothing in between sections, just butted right up. 
  The reo was already in place.  Moving down the shed I added more chairs. 
  I put plastic over the top after finishing, to keep it damp. In fact that plastic is still there, six months later. 
  Outside I went around with my trowel and battered the concrete down on each section as I poured it,  maybe ten or twenty mil to make sure the rain would run off.  This was a pretty rough, strictly by eye job, the 200mm lumps of metal in the concrete meaning I couldn't just easily slope it down but had to take out a trowel load here and there and then smooth it all down again.  
  That's all there was to it. 
 As a total novice I learned some things other total novices might be interested in hearing about. 
 Such as:   
. An old fashioned but typically sized mixer such as mine delivers only about one cubic foot of concrete.  i.e. about 300mm x 300mm x 300mm.  Not much. That's something like 28 loads for a cubic metre. 
.  Dry materials are 1.6 times the volume of finished concrete. i.e. for 1 metre of concrete I need 1.6 cm of dry stuff. 
.  Mixers such as mine don't empty cleanly. So there's stuff left inside between loads. Usually sand, wet sand. This effects the next load. Effects the amount of water needed. Water added to concrete acts light lightning. One minute you've got a dry mix and the next it is slop and all you  did was add a cup of water.  
.  Finishing is not such a black art, you (I) can do it. And it is important to do it else the concrete will have a dry, dusty, gritty finish on it. At least a bit of a once over. 
 That's about it, I think.  It's good fun. 
 Thanks to all who gave me their help. 
 ab   :Smilie:

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## Terrian

> .  Dry materials are 1.6 times the volume of finished concrete. i.e. for 1 metre of concrete I need 1.6 cm of dry stuff.

  yep, thats about right.  

> Water added to concrete acts light lightning. One minute you've got a dry mix and the next it is slop and all you  did was add a cup of water.

  I did say add water slowly  :Smilie: 
Don't feel bad, I still get caught sometimes, add some more cement to help dry the mix (while it is still mixing!) 
Good to see the job went well for you.

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## Wombat2

Just an interesting thought - don't know if this sort of thing is available elsewhere but in Brisbane there is a business called the "Concrete Taxi" the next door neighbour used them for some paths. They turn up with a truck - on the truck is a fixed cement mixer (small one) all the sand ,screenings and bags of cement. all the tools - trowels , screeds, barrows etc. All you provide is the labour ( next door used his sons  :2thumbsup:  ) The guy mixes the concrete as you need it and you only pay for what you use - comparable to ready mix but with all the gear as well. Pity they are not up on the coast where I have moved to  :No:

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## abrogard

I like the idea. It is a business opportunity, maybe. 
 Around our area there's another opportunity: concrete finishing.  Finishers are asking $1000 for finishing a 6 x 9 slab at 100mm, that's to say 5-6metres of concrete. Three of them on the job. Four hours would kill it. Ready mix concrete provided. All they provide is the labour and the know-how. $330 each for four hours work. 
 Probably accept cash. 
 Be hard work barrowing that much concrete into place, I guess.  I guess, I don't know. I'll work it out here and now:  
I don't know what the reach of the chute is but I guess it might go say three metres into the shed, maximum.  So they'd have to barrow the rest of the length.  6metres. Or two thirds of the shed. Say 4 metres of concrete.  
Builders barrows (I don't know if they bring their own) at say 15 to the metre is 60 barrow loads.  20 each in say the first hour. One barrow a minute. Should be easily achievable? 
Not even really hard work, eh? shoving 20 barrows an average of 3 metres over a period of one hour. No trouble. 
So they're not doing so much work. It's the know-how you're paying for.  
I wish I had it.    :Smilie:

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## Wombat2

They're every where - sort of  :Cool:   Concrete Taxi

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