DIY concrete patio questions

[Pirate]

We need to make a patio and was thinking of pouring it in sections.
Most likely no straight sides.
Questions:
1. If I pour in individual formed sections, how big can I go, without having any cracking?
2. After pouring first section and removing forms, is there something I should put in the joint between the first section and the new pour?
3. Can the material in the joint, be left there after the pour?
4. Is a slope of 4" in 20' sufficient?
5. Should there be any connection, between sections?
Any other suggestions would be welcome.
I have done a few small pours (8 x 10 store room floor and a few pours < 32 sf.)
We have a mixer and tools for the job. Only thing missing to do it fast is age, and a pain free back!
Thanks for any info.

[Robert Adams]

For #1 you can go as big as you want without cracking. It's all about how you do it. When a slab is poured for a house it's one piece. A 1/4 mile drag strip is one solid piece of concrere. Grain towers are one piece of concrete as are those massive oil rigs in the north sea.
When people say you have to have control joints in concrete it's because they are cheaping out on the slab. Do the prep right the right beams and rebar and do it all in one piece and you will always be glad you didn't put joints in the concrete.

#2 some put 1/4s between pours some use the black fiber board but personally those never turn out well in the long run. I prefer to pour up to the last pour.

#3 it usually is left in. Though some do remove it and use foam backer rod and a rubberized filler.

#4 depends on your rainfall etc. For me that's fine here.

#5 yes. Either have rebar sticking out of the current slab for the next or you will be drilling holes in the edge of the slab you just poured. If you don't the slabs can settle unevenly over time.

Good luck concrete and roofing are two things that I rarely do my self anymore. I would prefer to do it all in one slab. Just do your forms and rebar then have a concrete truck come out. Mixing your own concrete is much more expensive than calling a truck.
You can also rent a concrete dolly. It's a 4 wheeled bucket that you can use to get it from the truck to the back yard if the truck can't get there. They are becoming more popular as concrete pumps are $500 a hour here these days.

[KC]

Robert Adams said:

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For #1 you can go as big as you want without cracking. It's all about how you do it. When a slab is poured for a house it's one piece...

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Somebody needs to give the locals here some schooling.

[geek2me]

Robert Adams said:

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#2 some put 1/4s between pours some use the black fiber board but personally those never turn out well in the long run. I prefer to pour up to the last pour.

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Yes, definitely do NOT want to use the black fiber board.

[blackhat]

Are pavers an option?

[geek2me]

Pirate said:

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1. If I pour in individual formed sections, how big can I go, without having any cracking?

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10x10 is one rule of thumb. How long will you keep it wet? If you keep it soaking wet for a month, it is very unlikely to crack.

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2. After pouring first section and removing forms, is there something I should put in the joint between the first section and the new pour?

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Your rebar should span the joint, but you should not put anything else in the joint.

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3. Can the material in the joint, be left there after the pour?

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Don't put material in the joint, so nothing to leave or remove.

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4. Is a slope of 4" in 20' sufficient?

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You really want at least 1/4" per foot of slope, and even then will get some pooling water when it rains.

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5. Should there be any connection, between sections?

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Yes, rebar.

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Any other suggestions would be welcome.

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Hire it out - you will get a better looking, longer lasting result for not much more money.

[Lynden]

The design is a little dated, but if you like the look you could pour the patio in sections with wood dividers. Instead of using redwood or PT lumber for the dividers, use 2x6 Trex.

http://www.springwoodpaper.com/images/aw...nspirations.jpg

http://images.meredith.com/diy/images/20...8_06ab.jpg

https://www.quikrete.com/athome/images/patio01.jpg

[Pirate]

I'm leaning toward paying to get it done.

Like the song says. "And you know your over the hill, when your mind makes a promise, that your body can't fill" Old Folks Boogie. Little Feat