# Concrete slab for shed



## Nealtw (Jun 22, 2017)

How thick did you want it and what did you build it with. You can raise a 2x4 frame to 5" and it would be fine.


----------



## Ginfamous (Jan 8, 2021)

Nealtw said:


> How thick did you want it and what did you build it with. You can raise a 2x4 frame to 5" and it would be fine.


I want a 4" thick slab with up to 6-8 inches at the edges in order to support the weight of the walls and roof.
I used 2x6's but forgot to compensate properly for the depth of the thicker outer edge of the concrete to support the walls so at that depth it only makes like a 1"-2" thick slab. You think it would be fine to build an additional 12'x8' internal dimension frame out of 2x4 and secure that on top?


----------



## Nealtw (Jun 22, 2017)

Ginfamous said:


> I want a 4" thick slab with up to 6-8 inches at the edges in order to support the weight of the walls and roof.
> I used 2x6's but forgot to compensate properly for the depth of the thicker outer edge of the concrete to support the walls so at that depth it only makes like a 1"-2" thick slab. You think it would be fine to build an additional 12'x8' internal dimension frame out of 2x4 and secure that on top?


I would do it with 2x4s and raise it to the level you need, an inch or two off the ground is fine. 
brace it like this.


----------



## Ginfamous (Jan 8, 2021)

Nealtw said:


> I would do it with 2x4s and raise it to the level you need, an inch or two off the ground is fine.
> brace it like this.
> View attachment 639213


Ok. The bracing pictured, is that also done with 2x4s? Also, I was thinking of using a few scraps of 2x8 to connect the top form to the bottom form. Would this be necessary with the bracing you suggest?


----------



## Nealtw (Jun 22, 2017)

Ginfamous said:


> Ok. The bracing pictured, is that also done with 2x4s? Also, I was thinking of using a few scraps of 2x8 to connect the top form to the bottom form. Would this be necessary with the bracing you suggest?


set your frame in place, drive 2x4 stakes beside it, lift the frame to height and nail it, use your level as you go around and nail the frame to stakes and then place the back up braces to support it for the weight of the concrete.


----------



## Ginfamous (Jan 8, 2021)

Nealtw said:


> set your frame in place, drive 2x4 stakes beside it, lift the frame to height and nail it, use your level as you go around and nail the frame to stakes and then place the back up braces to support it for the weight of the concrete.


But, if doing that, won't the concrete spill out the bottom of the form?


----------



## Nealtw (Jun 22, 2017)

Ginfamous said:


> But, if doing that, won't the concrete spill out the bottom of the form?


We do an 8" footing with 2x6, if the concrete is running out under there is something wrong with the mix,.
After you have your form in, you can always throw dirt or gravel on the outside to lesson the gap.


----------



## Ginfamous (Jan 8, 2021)

Ok. 


Nealtw said:


> We do an 8" footing with 2x6, if the concrete is running out under there is something wrong with the mix,.
> After you have your form in, you can always throw dirt or gravel on the outside to lesson the gap.


Attached are a couple of pictures of the current state of the foundation. If I understand correctly, your suggestion is to simply raise the entire form by a couple inches to achieve the desired slab. As you can see, the surrounding area is not level, which isn't a problem over all just something we have to work around. The first corner is really my one concern as we were not able to dig it as deep as we would have liked.


----------



## Nealtw (Jun 22, 2017)

Ginfamous said:


> Ok.
> 
> Attached are a couple of pictures of the current state of the foundation. If I understand correctly, your suggestion is to simply raise the entire form by a couple inches to achieve the desired slab. As you can see, the surrounding area is not level, which isn't a problem over all just something we have to work around. The first corner is really my one concern as we were not able to dig it as deep as we would have liked.


Is the top of the form level now all the way around?


----------



## Ginfamous (Jan 8, 2021)

Yes


----------



## Nealtw (Jun 22, 2017)

Ginfamous said:


> Yes


So if you had built the form with 2x10 you would be in good shape. Just add to the top and add taller stakes.


----------



## dj3 (Apr 27, 2020)

Regarding your photos: You have re-bars holding the form, but you need to use stakes nailed to the forms. You want the form to be stationary.
1x3 or 1x4 stakes are fine, metal stakes are also fine. Use double head nails or screws to fasten them.


----------



## Ginfamous (Jan 8, 2021)

It was decided to go with raising the form to meet the height we needed for the slab. And yes, the form is currently being held in place with rebar. The area we are working in is still high traffic so we are keeping the trip hazards low until we are ready to pour the concrete. Thanks everyone for the input. ☺


----------



## jomama45 (Nov 13, 2008)

Seeing as your steel stakes are already below the top of the form, I'd suggest adding a 2x4 flat on top, screwed into the 2x6. If you need to go higher/ thicker, add a 1x4 into the mix. Using a 2x4 in this way will mean that you won't have to bother with bracing, most likely......


----------



## Ginfamous (Jan 8, 2021)

Being that it was our first big pour it was rough, but it seems like it went well over all yesterday. We did misjudge the set time of the first 4 feet so didn't get the J bolts in place properly in that section but oh well. Nothing a drill can't fix later. Thanks for all of the advice!! 😊


----------



## huesmann (Aug 18, 2011)

Hopefully you covered it up immediately after that photo was taken.


----------



## Ginfamous (Jan 8, 2021)

We had it covered over the first night, it's been raining pretty steady since early morning yesterday. We were going to spray it with acrylic curing and sealer, but according to the bottle it is too cold and rainy here for that. Everything we've read so far has indicated that leaving it open to the rain is just as good as watering and covering. Did we misunderstand something and need to alter our curing treatment?


----------



## huesmann (Aug 18, 2011)

I guess it depends what kind of surface you want? I would think rain could leave it pitted.


----------



## jomama45 (Nov 13, 2008)

Ginfamous said:


> We had it covered over the first night, it's been raining pretty steady since early morning yesterday. We were going to spray it with acrylic curing and sealer, but according to the bottle it is too cold and rainy here for that. Everything we've read so far has indicated that leaving it open to the rain is just as good as watering and covering. Did we misunderstand something and need to alter our curing treatment?


No, don't change anything. Cold/wet/damp are the perfect recipe for strong concrete. As long as it wasn't allowed to freeze for the first 2-3 days (surface temperature, not necessarily air temp) you'll be fine.


----------



## Ginfamous (Jan 8, 2021)

huesmann said:


> I guess it depends what kind of surface you want? I would think rain could leave it pitted.


Ok, for clarification: the slab was covered for the first 12 hours. The surface was hardened and not prone to be deformed by raindrops (especially tiny baby Washington raindrops) when this picture was taken. 😆


----------



## Nealtw (Jun 22, 2017)

Even if you had a little surface damage, it's a shed. If you don't see anything now you are good.


----------



## WendyPayne (11 mo ago)

Construction of a large barn takes not only a lot of effort and energy, but also a lot of money.Well I know this from my own experience.At the age of six my parents bought a plot and began to build our house and barn. At that time it seemed to me that it was easy enough, you only need to have money to do it, but building a house takes a lot of effort and patience. Would have known my parents at the time that there is such a great site where the best concrete contractors . I am sure that their life became much easier and the construction of our barn accelerated by three times. Why do I think so? Because I have already built my own shed with the help of these guys, my family and I are very happy. So if you want to make your life easier when building your house or shed, I recommend them.


----------

