cost estimate - 20x30 concrete footing

[amarlow]

Hey y'all. In need of some experienced guestimating.

I've been "designing" what will the first building on our vacant property -- a 20x30 foot barn in which to store the new (to us) tractor. I very much like the look of Seth's 20x20 shed/mini barn with loft, especially the 12:12 pitch of the roof, and have been planning on copying him almost exactly, except for increasing the length to 30 ft.

His barn uses pole building construction techniques, sinking large 4x6 or 6x6 pressure treated posts below the frost line, and that is what I have been planning. Until now. I am wondering if I should go with what I'm sure will be a more expensive poured concrete footer & concrete foundation wall.

Here are the parameters of the (desired) building:
-- 20x30 foot print
-- 9 to 10 foot interior wall height
-- ~12x30 lean-to open shed along one side for implements
-- attic trusses to allow for 2nd floor "loft" storage area
-- "rat wall" required to minimum 18 inch depth
-- for now will be a dirt floor
-- initially used for secure storage of tractor, workshop
-- someday will have a poured concrete floor
-- someday will become the critter barn, for goats, chickens, maybe a pig, feed storage, milking stanchion, etc.

I think I just attached an image of what I've drawn so far.

Now, as I said, I'm thinking I should just bite the bullet and go for the concrete footing/foundation. This is especially true because of the last item, that someday, not too far down the road, I'll be converting this to use as an animal barn.

One key piece of information: The area chosen for the barn slopes downhill from back to front about 18 inches over the 30 feet. This means if the foundation wall on the back side is say 6 inches above grade, it will be 24 inches above grade at the front. Add in the 42 inch footing depth, and it means the foundation walls will be 5.5 feet tall. Yow!

Anyway, before I actually call an excavator out to look/quote, I'd like to get an idea what this might run me. I'm sure the answer is highly dependent on the region where I live (midwest US). But would any one like to estimate what it would cost, not counting the actual concrete, to dig down 6 ft for footings, put in those footings, then pour a foundation wall 5 to 6 inches wide by 5+ feet tall?

Thanks in advance! I really have no idea what to expect.

~Allen

 

[cycle_gator]

Amarlow:
"One key piece of information: The area chosen for the barn slopes downhill from back to front about 18 inches over the 30 feet. This means if the foundation wall on the back side is say 6 inches above grade, it will be 24 inches above grade at the front. Add in the 42 inch footing depth, and it means the foundation walls will be 5.5 feet tall. Yow!"

Are you positive about the footing depth? Do you know how much it costs per yard of delivered concrete? Are you planning on formimg and pouring this yourself?

 

[TU1900F]

Hey y'all. In need of some experienced guestimating.



Anyway, before I actually call an excavator out to look/quote, I'd like to get an idea what this might run me. I'm sure the answer is highly dependent on the region where I live (midwest US). But would any one like to estimate what it would cost, not counting the actual concrete, to dig down 6 ft for footings, put in those footings, then pour a foundation wall 5 to 6 inches wide by 5+ feet tall?

Thanks in advance! I really have no idea what to expect.

~Allen

I'm NOT a builder or an architect or a building inspector so take what I say as mere suggestions.
I have put up at least a dozen or 15 barns, sheds, etc & 3 homes over the years. I don't mean that I paid someone else to do the work, I design & build all my stuff, including the earth moving & foundation work. Most of my out-buildings are pole type construction & post & beam construction.
One home I built is pole construction, one is conventional stick construction & the one I'm finishing up right now is all steel & concrete. (1800sf hurricane shelter).

All that being said, You could dig out for those footers & float the slab in later at any point you'd like or, you could form it out now & pour a monolithic slab. The monolithic slab floats on the frost & some say they resist cracks better. They are also easier to put in and there is a lot less form work. Both are bank breakers and I would NOT recommend you dig footers for a building that is to be used as described. There is just no reason for it AND if you plan on housing critters in that crib, you really need to rethink the whole idea of concrete floors. I'm sure there are many folks who would argue that concrete is great for keeping animals but I've raised barnyard critters for 30 years & I can tell you that they are happier & healthier on dirt that is kept well covered with fresh litter (hay, straw, etc).
Winters are tough on all critters & even worse when they are housed on cold damp hard urine impregnated cement.

Your animals will love you & your bank account will love you.
Go pole construction & save your money for tractor implements!

Good luck whichever route you choose.

 

[crazyal]

If this is going to be a barn have you thought about doing an Alaskin floating slab?

 

[Ken45101]

I don't know about the animals you plan, but concrete is definitely bad for horses.

I'm not a builder, but don't see the need for deep footers for a pole barn. We had a big pole barn put up last year with a 6" slab floor poured as the last step.

 

[forgeblast]

Look up "rubble foundation" frank lloyd wright used them.
I used a version for my garden shed that i am building. I dug down to frost line, put in drainage that sloped to daylight. back filled with gravel until i was 12'' from surface. put in tar paper and my rebar and then poured concrete to give me a level base to start setting field stone. its held up through some nasty wet winters and summers.

 

[BHD]

if you want a foundation like that, and do not want to spend big bucks,

for a poured foundation one would need to form it up and do a lot of excavations to properly do that,

but if all your looking for is a "rat guard" as you call it, and some thing to go down below frost line,
(if your going with a pole barn the foundation is in the posts) (simply it is pier foundation)
and the building is not that heavy to require a massive foundation even if stick built,

getting back to the quick wall, call out a trencher, and have them trench about 4" to 6" trench the desired depth and fill with concrete, if one wants put a few 3/8" rebar in it so it can pin to the floor/ footer, now if you want a footer do that on top similar to a floating slab, with the floor, or in other words keep the wall about 8" below the surface of the proposed floor, and then after the rat guard is poured, form up a footer that will set on top of the rat guard, and the wall will set on, this could be hand excavated, or with a small back hoe, for the footer I would pour the floor when your doing it, if your you going to use as shop you will not regret a good floor, and to work off of building the building, (a common footer would normally be considered 8" thick by 16" wide, for a home in our area) by the time one gets a ring 16" wide around the out side of the building, one might as well pour the floor, but if your going footer only (no floor) I would build a box in the form and reduce the width of the top in some so there is not a seam to the floor 10 " out from the wall) some what how a brick ledge is done in a house wall, but on the inside so the floor will be closer to the inside of the wall,

HowStuffWorks "How House Construction Works"


(for the animals build a second shed, and leave the dirt floor,)

when I poured my floors on my shop,
I money was tight as well
30' x 48' I knew trucks and tractors would be pulled into the shop down through the center of the shop I did a full 6" pour and where the actual tires path was going to be increased to 8" from the door for about 30 feet in the building, but on the out side of that I reduced it down to 4" under the benches and along the out side walls, where I knew only foot traffic would be,

the only crack I got was where the redi mix company would not sent two trucks that day back to back and I ended up with what is referred to a cold joint between the two truck loads as one was nearly an hr later. and I built the shop nearly 20 years ago,

if you do want a full stem wall foundation one may consider concrete block and fill the cores setting on a full footer,
similar to this, stem wall foundation — Build My First Home | The trials and tribulations of building a first home

not the fondest of this way, but for a stem wall should work well,How to Build a Mortarless Concrete Stem Wall - wikiHow
(Note there are special block with knock out for putting rebar in the horizontal way, called "knock out bond beam" . http://www.concretebuildingsupply.com/content/pdfs/8X8X16 KNOCK OUT BOND BEAM.pdf

this is what I think a block stem wall should look like (mortar or no mortar), before concrete fill, File:Bond-beam.JPG - Wikipedia, the free encyclopedia

my guess the cheapest and fastest method for the foundation you want would be to trench and then pour a floating slab over the top of that,

the second would be to get a back hoe out, and pour a full footer, and then either the foam block or the concrete block build a wall, (I would suggest the mortar) and then rebar and core filled with cement,

the absolutely best is the footer, and a form poured properly reinforced concrete stem wall 6" to 8" thick, IMO, and most likely the most expensive.

IF I was building my own 30 by 40 shop, I would trench and work that way, if the soils will support the trench wall, I would not go down that deep here, but that is my situations,

( I realize I have not given any cost estimates, but I do not currently even know what going rates are in our area alone in yours),

if you want a price I suggest you call a concrete contractor or a masonry contractor and explain to them what you want and work from there,

edit:
here is a fairly good picture story on building useing poured stem walls and how it was done,
http://www.libertynaturepreserve.com/garage-apartment.htm

 

[handirifle]

Now I do not live in Mich, I do live in central coast CA, climate issues are a lot different. I did just finish a 24x30 workshop/storage building. I also had a slope to contend with, but knew in advance what I was dealing with.
Mine has a 12"x12" "footer (yes the upper was only 12" in the ground), but the lower portion had to have an 18" wall on top of it to bring it to level. I took my MF1010 over the short uphill side and back filled the "wall" area to bring the subsoil level with the upper level . I used the tractor and a lot of water to compact this soil, and then 5 inches of sand, compacted as well. On top of this was 6" of fully rebarred slab floor.

The walls are 10', 2x6 standard construction, with 3/8" OSB sheathing on all sides.

I give all these details to understand. I bought the materials, but had a contractor bid on the slab/framing work. For $8200 I got the foundation dug, the forms made, the footings, and slab poured (this 8200 DID include the concrete). It cost another $3200 for the framing labor. These are things I could not do, at least the concrete was, and the framing would have taken me 10 times longer. Money well spent, too me.

The way our building codes are here, pole barns are nearly as expensive.

Thinking about your job, could you rotate the shop 90 deg? That would put the downhill wall only 20ft away and not 30. This might make the subwall considerably shorter. Of course that depends on a lot of issues, I'm sure, like entry availability, usage, access etc.

Let us know what you do.

My brother in Ohio, had his pole barn made as was suggested by one here, the barn was built and the slab poured in afterwards. His is 60x100x16 so the concrete trucks just drove right in.

 

[bjr]

Pole barn, Pole barn. Around these parts, that's all anyone knows. Most of us are too afraid of the building codes to get creative. They don't last forever, but, they're all most folks can afford. bjr