Pouring a new slab in sections

[fred d]

Is there any reason why I couldn't pour a slab 14'x20' slab in 4 sections?

If so, Anything I need to make sure I do or don't do

I am thinking that if I run the rebar thru the dividing boards it could work


An alternate idea, could I pour the footings, then build an addition, then pour the floor at a later date?

 

[COBRA5LADDICT]

that is how I had to pour my 30x50. it was just me an 1 other guy so all we could work was 10 width at a time. did 3 pours, after each pour we drilled rebar into the previous pour to tie it all together. slab is 5.5-6" thick It turned out nice for how much it saved me doing it myself.

of course this was just a slab inside my new pole barn so no footings were necessary

 

[trbomax]

Thats small enough to easily do with 2 people.there were only 3 of us when we poured the floor and footings at the same time,its42 x 72. We used a laser robot to hold the elevation, so there really wasnt much screeding.One guy on the trowel. two of us were old guys,64 and 65 too. All the above said,I wouldnt try that now,I would probably do 3 sections.But if you do the footing first,then do the slabit would be easy. Can the trucks get close enough to chute it? thats a problem with only 2 guys.

 

[rburke65]

Well, at 20'x14 that is 280 sq. ft., and that would be 3 1/2 yards of concrete. If you did the entire floor at one time, they are going to charge you extra for only 3 1/2 yards of concrete. And if you pour it in 4 sections, that's going to be 4 extra charges. Would a 'ready mix' company even deliver a one yard load? Probably would for the money. Just some random thoughts on the concrete delivery end of this idea. Good luck.

 

[trbomax]

For 1 yd I'd mix it myself.No one will deliver 1 yd for any price,at least not here.

 

[SteveCh]

I did two 14 x 22' pads this way, and a 12 x 23' greenhouse floor. Greenhouse holding up perfectly after 24 yr. and the other pads, floors for my carport and tractorport, look good after ten yr. So, yes, no problems. I did them all with a wheelbarrow and home electric concrete mixer.

 

[fred d]

I figured way more than 3-1/2 yards so my question is did you figure the slab with a footing?
I am figuring a 12" wide x 12" deep footing and a 5" thick slab

It is just a 3 wall addition so I may be going overboard on the dimensions

I really don't want to bag mix it, I think I can get 1 yard pre mixed cart that I can tow with my truck and dump in the location

 

[yucholian]

2 newbies can pour that slab in one shot.
In fact, my FIL and I did just that for my shed

 

[fred d]

Can't get a truck close enough chute it, I can get a trailer thru the garage to pour out the back wall

Will bag it if I absolutely have to

 

[NUTTSGT]

I figured way more than 3-1/2 yards so my question is did you figure the slab with a footing?
I am figuring a 12" wide x 12" deep footing and a 5" thick slab

It is just a 3 wall addition so I may be going overboard on the dimensions

I really don't want to bag mix it, I think I can get 1 yard pre mixed cart that I can tow with my truck and dump in the location

I doubt he figured the footer as I came up with about 3.5 yds also. You asked about the slab and only asked about the footer as an after thought at the end of your post. You also provided no information about the footer which it makes it hard to answer any questions about it.

Personally, I would pour the foundation first, stem walls?? then the floor.


FWIW, adding your location to your profile will help people answering your questions. Different parts of the country or different countries have different building requirements.

 

[fred d]

I doubt he figured the footer as I came up with about 3.5 yds also. You asked about the slab and only asked about the footer as an after thought at the end of your post. You also provided no information about the footer which it makes it hard to answer any questions about it.

Personally, I would pour the foundation first, stem walls?? then the floor.


FWIW, adding your location to your profile will help people answering your questions. Different parts of the country or different countries have different building requirements.

A bit more info
This is a 3 wall addition to the back of my garage(back of the garage being the 4th wall)
Planning on drilling into existing slab and driving rebar into slab to connect both slabs


Thanks for pointing that out about the footing.
I am figuring about 6 yards total, does that sound right?

What are stem walls

In the Metro Houston area, will try and update profile

 

[Ray Kelly]

I've done this- poured it in sections. It held up well.

 

[fred d]

Did you leave the boards in that separated the sections or remove them once the first section was dried

 

[fred d]

OK getting ready to do this

Questions

1. Have been thinking.....if I pour just the footer first, then poor the floor it would give me a smoother main floor. Then I could get the walls up and dried in before pouring the main floor.

The way I figure it 18x14 addition
Footer is 12x12 I have 44 liner foot of footer then that equates to 44 cubic feet or about 1.5 yards of concrete.

My main floor pour would be 16x13. At 4" thick that is right at 2.5 yards

Please give any thoughts you might have good or bad
Also let me know if you think my calculations are off

 

[jkwilson]

Unless you are planning on the footer standing 4" out of the ground, what are you going to put your walls on to build them before you pour the slab?

If you are planning on the footer being high enough to rest the walls directly on it, it's only going to be 8" in the ground below the slab. Not sure I'd bother with a separate pour for that.

If you want your walls sitting directly on the footer, you'll have to form up a small stem wall to keep them above grade.

Normally when doing a slab in multiple pours, you pour every other section, let them cure enough to pull the forms, drill and insert rebar, and then pour the remaining sections.

 

[volleyball]

I like to drill the 2X and install rebar through it so no drilling later. drill an oversize hole put tape over it, slit it and push rebar through.
I also put foam under the slab to slow heat transfer.

 

[fred d]

My "plan" was to set forms with rebar in place drilled through holes in internal forms
That way I had no drilling to do once section was poured

 

[Leaflessshadetree]

If the slab will be sitting directly on the footer (what people refer to as a thickened edge) I'd pour those and the slab at the same time. If the footers will have a wall on them I'd pour the footers, then the walls, then the slab.

You can divide the slab in 4 (10x7) sections. Pour 2 diagnal sections at a time to avoid the short load charges (they probably can't haul enough to do it all on one truck anyway).
Drill for rebar when you pull the forms off the first two sections. Drilling new concrete is a lot easier than messing with rebar poking through the forms.

 

[fred d]

If the slab will be sitting directly on the footer (what people refer to as a thickened edge) I'd pour those and the slab at the same time. If the footers will have a wall on them I'd pour the footers, then the walls, then the slab.

You can divide the slab in 4 (10x7) sections. Pour 2 diagnal sections at a time to avoid the short load charges (they probably can't haul enough to do it all on one truck anyway).
Drill for rebar when you pull the forms off the first two sections. Drilling new concrete is a lot easier than messing with rebar poking through the forms.

I will not be getting this delivered.
I will be getting a short trailer with 1/2 to 1-1/4 yard capacity

That is the reason for doing it in sections.
I have been told that a concrete truck would be too heavy on a residential driveway. So it will need to be wheelbarrowed in

I thought I would pour the 12x12 footing around the edge
When poring the main floor it would only come to the same level as the top of footings, not over. Also the walls will be stick built once footing/slab is done

 

[jkwilson]

I will not be getting this delivered.
I will be getting a short trailer with 1/2 to 1-1/4 yard capacity

That is the reason for doing it in sections.
I have been told that a concrete truck would be too heavy on a residential driveway. So it will need to be wheelbarrowed in

I thought I would pour the 12x12 footing around the edge
When poring the main floor it would only come to the same level as the top of footings, not over. Also the walls will be stick built once footing/slab is done

If the footer isn't going to be taller than the floor, pour them together.

You can rent a concrete buggy for about $100 a day most places. It will haul a half yard at a time. IMO, it would be worth it to just have the concrete trucked, buggy it to the slab and pour everything in a single pour. The amount of time, labor and material you'd waste forming the footer would pay for the buggy.

Just tell them you'll have to carry the concrete when you order it so they know to be prepared for a little more onsite time.

 

[rburke65]

You never gave a dimension for any footer. You asked about a slab. I'd pour it in one shot. I'm sure you have a couple of buddy's and you can do this.....I know you can. How about some You Tube Videos on concrete finishing? Good luck

 

[fred d]

You never gave a dimension for any footer.

Stated earlier
The footings will be 12" deep by 12" wide

One shot pour is not feasible.
Trying to do this on the QT.
Don't want to draw attention to my project.
That is the reason for the sectioned pour.

Do I need more than a 4" slab if I will not be using it for more than anything other than a woodshop/storage area

 

[Leaflessshadetree]

4" slab will probably be fine. (You haven't mentioned any reinforcement or your location).
Not sure what you plan is, sounds like you are going to pour the slab inside (not on) the footers. You will probably will want to make the slabs thicker around the edges. Also that will leave a seam around the edges, not a smoother floor.
The difficulty with drilling the forms for the rebar could be in pulling the forms off afterwards. Your probably not planning on reusing them so cutting them in pieces is an option.
Not sure how far you have to go to get the concrete (don't have the trailers near me). Will the concrete set up before you can get another load there (if you run short)?

 

[brownbagg]

for the section between slabs, instead of rebar you really need smooth bars, and before you pour the second section grease up the bar. that way the slab can slip a little and not crack the slab.

put the bar in the concrete while it still soft so it can grab the bar

 

[bdymnjm]

Fred D, If you are in an area with little to no frost I wonder if you could build a shed on grade with treated wood skids and plywood floor. Tie it down as needed for wind lift. If you really can't bring a concrete truck to your house, save the effort and money of the concrete floor.

Jim

 

[fred d]

4" slab will probably be fine. (You haven't mentioned any reinforcement or your location).
Not sure what you plan is, sounds like you are going to pour the slab inside (not on) the footers. You will probably will want to make the slabs thicker around the edges. Also that will leave a seam around the edges, not a smoother floor.
The difficulty with drilling the forms for the rebar could be in pulling the forms off afterwards. Your probably not planning on reusing them so cutting them in pieces is an option.
Not sure how far you have to go to get the concrete (don't have the trailers near me). Will the concrete set up before you can get another load there (if you run short)?

Sorry, I assumed that everyone could see under my name It says Metro Houston area, very seldom does it freeze....even for a little bit
I will be using rebar in the slab to tie it all together
A seam around the edge where the footing ties to the slab is not a problem. shelves and larger tools will be along the walls so the seam will never be seen

 

[little d]

Fred,
the first thing I'd do is dig down where your footer would be. This will tell ya what the builder did...floating slab (no footer, 6 to 8" thick), mono (footer and slab poured together, 12 +") or footer then slab (you will see a "dry" seam).
If they did a floating slab, you wont need a footer, just dig down deeper for a thicker area for framing the walls (pin into what is there already), if they did do a footer, ya need to match what is existing and yes pin into it. If you do a footer, from what you have posted, I'd suggest ya pour it ground level leaving the vertical rebar sticking out (those orange plastic caps you see on jobs will help to keep people from getting hurt on the rebar sticking out)to tie into the slab and then pour the slab when ya want but, before ya build the walls. This sounds like your first time so you are going to need all of the room you can get to get the floor flat and finished and yes you can pour the floor in sections.