Good fill / floor base?

[BertoBuckeye]

Hey guys.

I'm working on getting the estimates I need to put up my barn and i'm slowly finding out that the earth moving part of my project is going to be prettttty pricey.

My question is for a pole barn, with 6" of concrete planned. What is the best material to use to make a nice flat pad for the shop? It needs to build up about 8" in the shallowest corner and 24"+ on the deepest corner.

I've had 3 different contractors tell me varrying things.

- Contractor (1). Suggested using 'Ag Lime' for the pad. Says it will compact very well. Said not to use 'Pit Run'
- Contractor (2). Suggested using 'Pit Run'
- Contractor (3). Is a concrete guy as well and said to absolutely NOT use any lime.

This is my first go at this kind of stuff and a little unsure with which one to go with. Any help or guidance is appreciated!

 

[dbabicky]

Pit run is a ***** to work with when it comes to "fine grading". (stones are too large) I had my own concrete business for several years, what I would use for fill is 1-1.5 inch crushed gravel to get you about 3-4 inches from grade then use fines to get you to grade from there. Poor your 6 inch slab on top of that and you'll be just peachy. Make sure you use a compactor or at least drive the skid steer over it as you add every 3-4 inches of material. Just make sure to compact it no matter how you do it.
You could use pit run to get you within that last 4 inches but the **** is just a pain to try to level out . It is generally cheaper though, just more labor intensive and not worth it in my book.

 

[TonkaJoe]

I work in Construction building roads etc.. Maybe some insight will help! 1- AG Lime does compact well and is used in construction often to dry up haul roads, or muddy areas of a work site. However, in the longterm lime does expand and contract in varying temperatures ( mostly cool to cold) which will eventually cause it to break down turning it into powder and causing your slab to likely crack or sink. 2- Don't use Pit run.. it's an unmanufactured aggregate which is simply dug up in it's natural state. There aren't enough fines in the aggregate to allow it to properly compact, it has rocks up to 12″ , but typically 6″ or less. It is used for a base in roads and driveways and should be placed in layers 12″ thick or more. By going this route you'd need to excavate deeper into your sub grade. BUT.. The less disturbance to your subgrade the better. 3- In case it's brought up I'll mention 3/4'' Clear.... 3/4'' clear gravel is a washed product unlike the 3/4'' Crusher run that is used as a base only when compaction is not possible. it's used extensively for drainage applications and in the manufacturing of Cement and Asphalt products. The many voids around the stones allow water to flow freely though it. The same voids can be filled with different gradation of stone products in combination with a cement to create a hard concrete product that can be molded into almost any shape. 4- My suggestion to you.......... 3/4 crusher run.. generally with 10-30% of fines for the best compaction rate. What's your sub grade consist of?. You might get away with one lift in most areas, but in those problem corners I'd definitely plan for 2-3 lifts, and remember compaction is key to a base!. Pack that floor after each lift till you are blue in the face.. you can even moisten the area more than once really well too, that will assist in compacting the area prior to concrete. It would also help to let the area settle for a few weeks before the pour. Hope this helps!

 

[TonkaJoe]

Pit run is a ***** to work with when it comes to "fine grading". (stones are too large) I had my own concrete business for several years, what I would use for fill is 1-1.5 inch crushed gravel to get you about 3-4 inches from grade then use fines to get you to grade from there. Poor your 6 inch slab on top of that and you'll be just peachy. Make sure you use a compactor or at least drive the skid steer over it as you add every 3-4 inches of material. Just make sure to compact it no matter how you do it.
You could use pit run to get you within that last 4 inches but the **** is just a pain to try to level out . It is generally cheaper though, just more labor intensive and not worth it in my book.

^ +1

 

[pstnbly]

We use 1.5" crushed stone for the initial lifts and .75" crushed stone for the last lift. Crushed stone compacts better and is free draining. If you live in a frost zone you don't want material with fines as it will hold moisture and heave.

 

[ImpalaJon]

Timely information as I'm calling excavators today to get estimates for site prep on a barn and a shop. Based on feedback I've received from several builders I interviewed and from friends, good quality excavation work is key but is also apparently hard to find in this area.

 

[Mandres]

Around here a lot of people use crushed concrete. If you have a local source it's cheap and effective.

 

[JACDes]

too much slang around here.

just ask for CA-7 ( aka 3/4" crushed stone with no fines )

it will compact and is a frost proof material, if used correctly with rigid insulation the slab will not heave.

 

[PAToyota]

just ask for CA-7 ( aka 3/4" crushed stone with no fines )

it will compact

Actually, you need the fines for something to compact. If it is just 3/4” it will always remain loose.

 

[JACDes]

Actually, you need the fines for something to compact. If it is just 3/4” it will always remain loose.

Incorrect,

CA-7 can most certainly be compacted and that has been verified in the field with Nuclear Density testing.


CA-6 (with fines ) is also acceptable, and can used WHEN FROST IS NOT A CONCERN.

Ask any soils engineer, EXCAVATOR, CEMENT FINISHER, ENGINEER, OR ARCHITECT who actually knows their trade.

 

[ishiboo]

We use 1.5" crushed stone for the initial lifts and .75" crushed stone for the last lift. Crushed stone compacts better and is free draining. If you live in a frost zone you don't want material with fines as it will hold moisture and heave.

This.

Crushed limestone probably works wonders initially and it's cheap, and it's a decent topper for a "gravel" driveway... not what I would want under my concrete though.

 

[ishiboo]

Ask any soils engineer, EXCAVATOR, CEMENT FINISHER, ENGINEER, OR ARCHITECT who actually knows their trade.

P.S. If you don't know what Nuclear Density testing is I don't have the time to explain it to you.

There are better ways to express yourself without sounding like the Nick Burns of aggregate.

 

[JACDes]

OH yeah,,, YOUR WELCOME !

LOL

 

[ishiboo]

OH yeah,,, YOUR WELCOME !

LOL

Hahahaha well played

 

[PAToyota]

For talking about slang, I’m unfamiliar with what “CA-7” might be. I typically go by the AASHTO (American Association of State Highway and Transportation Officials) designations for specifications. “CA-7” is turning up Department of Labor claims for compensation, job scheduling / workflow automation software, and other things in Google searches.

From your description of “aka 3/4" crushed stone with no fines” I took CA-7 to be a “clean” stone of single size (like AASHTO #67) as opposed to a “modified” stone of varied size. Clean stone stays loose and drains well, but will not stay compacted in unconfined placement.

 

[NUTTSGT]

This.

Crushed limestone probably works wonders initially and it's cheap, and it's a decent topper for a "gravel" driveway... not what I would want under my concrete though.

Limestone is used extensively around here as it is plentiful with many quarries. Depending where the OP is considering his user name, there just might be a National Lime and Stone quarry near him.

 

[BertoBuckeye]

I will make sure to fill out my profile info, but I am in Columbus, Indiana.

Another contractor quoted me with '73 stone' which I don't know what that is either. All these terms are difficult to follow!

 

[cj7jeep81]

I will make sure to fill out my profile info, but I am in Columbus, Indiana.

Another contractor quoted me with '73 stone' which I don't know what that is either. All these terms are difficult to follow!

I'm not too far from you, and am building my pole barn now. I used 53's for the bottom 4", and 73's for the top. 73's are smaller, with fines so it packs down super tight.

 

[PAToyota]

The other recommendation I’d make is to be sure they put down geotextile fabric before any fill - otherwise it will just compact into the sub-base over time. Some will argue that it isn’t needed, but it is cheap insurance for doing it right.

 

[LB-1911]

Another contractor quoted me with '73 stone' which I don't know what that is either. All these terms are difficult to follow!

Links below will help you decipher a few of the terms -

US Aggregates
http://usagg.com/construction/


Quality Aggregates Of Illinois LLC
http://www.qualityaggregates.com/rockford-il-aggregate-stone-products.htm

 

[PAToyota]

Links below will help you decipher a few of the terms -

It just goes to show how much variation in terms there is from region to region. I am surprised that they don’t correlate their terms to AASHTO at all. Around here they’ll typically give the PennDOT designation (like “2B”) along with the AASHTO designation (AASHTO #57).

 

[JACDes]

For talking about slang, I’m unfamiliar with what “CA-7” might be. .

IL DEPT OF TRANSPORTATION IDOT gradation CA-6, CA-7, CA-1 , etc which is based on

ASTM D 2940.

regionally state use their own gradation but all are based on

ASTM D 2940

 

[jimp]

I used concrete truck washout, it cost nothing but transport and compacted very well. Slab has been in place 15 years, no open cracks or settling. It's the only thing I would ever use.

 

[rburke65]

Wow....it's no wonder why the average guy is confused with all the opinions flying around here. I am not throwing stones at anyone.....or lime stone....or is it #57.....or is it CA7? Just saying.....

 

[Jokenring]

I just finished my pole barn and used 1 1/4" minus (1 1/4" stone with fines) over geotextile fabric. It packed very well and made a good base. As a note, don't go and get your pad perfect before they start building, they will just screw up your perfectly packed pad. Once the building is up go back and level. Running string line from the bottom of the ledger board zig zagged across the pad makes a nice line to level to.

 

[Bondo]

I just finished my pole barn and used 1 1/4" minus (1 1/4" stone with fines) over geotextile fabric. It packed very well and made a good base. As a note, don't go and get your pad perfect before they start building, they will just screw up your perfectly packed pad. Once the building is up go back and level. Running string line from the bottom of the ledger board zig zagged across the pad makes a nice line to level to.

Ayuh,..... I work in stone 6 months a year, startin' my 23rd season soon,....

We do like Jokenring,....
Inch, 'n 1/2" Minus, for rough gradin' with the machines, 'n poundin' it in tight,...

Then shim out the top couple inches in 3/4" Minus,...
Much easier rakin' to the strings,...
Then pound it again,...

I've never seen washed stone, No fines compact worth a damn,...
It just keeps movin' under the roller,....

If the fill is much over 18", We might start out with 4" Minus, 'n shift to 1, 1/2" at a foot or so, then top it out with the 3/4" Minus,....

I'm also very spoiled, All the stone We used is crushed limestone,......

Little to no gravel 'round here,.... just clay, 'n solid limestone,...

 

[Firebird 1]

What are you parking in it? Aside from the fill, I think the question has been answered, plus I have no idea what they use in your neighborhood, I question why you need 6" of concrete. If the slab is prepped correctly, and wire and rebar used 4" should be more than adequate. I use 6" slabs when parking fire trucks, but no need in a conventional garage. Youre wasting your money.

 

[pstnbly]

Actually, you need the fines for something to compact. If it is just 3/4” it will always remain loose.

Not true. I've been in the excavating business 35 years, false information.

 

[BertoBuckeye]

Wow there are a lot of conflicting ways to do this, even on here. Glad to get your opinions!

What are you parking in it? Aside from the fill, I think the question has been answered, plus I have no idea what they use in your neighborhood, I question why you need 6" of concrete. If the slab is prepped correctly, and wire and rebar used 4" should be more than adequate. I use 6" slabs when parking fire trucks, but no need in a conventional garage. Youre wasting your money.

I'm putting in a lift, so want to be on the safe side for the concrete. And If I want to store a tractor or camper or whatever in the future I don't want to worry about where i park it! In the grand scheme of things extra 2" of concrete isn't a big deal.

 

[KenC]

Wow there are a lot of conflicting ways to do this, even on here. Glad to get your opinions!




I'm putting in a lift, so want to be on the safe side for the concrete. And If I want to store a tractor or camper or whatever in the future I don't want to worry about where i park it! In the grand scheme of things extra 2" of concrete isn't a big deal.

That is a 50% increase in material cost. Would be a big thing to me, or to a customer in most cases. I'm all for building right, but overbuilding with no real improvement in function is not in my plan.

 

[hoppsxc140]

I work in road/highway/site construction. I would suggest cutting the existing grade and using that to balance out some of the fill area. Then a subgrade separation fabric or geo-grid. Then find something either recycled concrete, pit run, crusher screenings, something cheap and bring it up to within 1 foot of your finished rock grade, rolling every 4 to 6 inches with water as the material is being placed/rolled. Then an even 8 inches of 1-1/4 minus, with the same 4-6 inch lifts, and finally 2 inches of 3/4 or 5/8 minus. This may sound like quite a bit of work but it will lessen the compaction differential of one area of like material being 24 inches thick and another area only being 8 inches thick. I would advise to top off any material with 3/4 to 5/8 minus to minimize any "bony" areas that would eat up mud. Rock is cheaper than mud and if your concrete guy isn't doing the prep work chances are he will come back on you when he overruns on concrete. I would also suggest overbuilding the low side since the edges of fills don't get the same forces applied when being rolled.

When the rock is being placed it needs to have moisture in it. Optimum moisture for our pits is between 8-11%, when its this wet it will almost look like concrete, the fines will bind to the larger rock and when it is rolled and hard it will have a very shiny finish and possibly some standing moisture on top, this is fine since once it dries it will be hard. I would consider contacting a local material lab in your area and having them come take a test or two if you are skeptical of the practices of the contractor doing the work. Our area the labs charge 150-200 to come out and pop a couple of holes, and if the material is coming from a known supplier they will have a proctor specific to the material they are testing.

Not knowing the size of your building I'll use the one I will be starting soon as an example.
40x60 with an average 1.51 ft fill

2400x.51/27=45 Cy x 1.9 = 86 tons at $5.00 a ton = $431
2400x.83/27= 73 Cy x 1.9 = 140 tons at 7.70 a ton = $1079
2400x.17/27= 17 Cy x 1.9 = 32 tons at 7.70 a ton = $248

Roll of fabric $300.00

2 operators $27/hr for 20 hours = $1080
small grader $55/hr for 20 hours = $1100
small roller $35/hr for 10 hours = $350

258 tons of material @ 25 ton per load = 10 loads
10 loads at 30 min a round, 5 hrs of truck time @ $85/ hr = $425
Miscellaneous/mobe $500

I'd bid it at $5513 plus tax.

Another note about compaction. All material can be compact. The difference is in the materials maximum density. Course rock or rock with no fines, pea gravel, 3/8 clean, sand, 1 inch drain rock typically achieve maximum density simply being placed in a confined area. I have fixed many soft spots in roads simply with a separation fabric and 1 inch drain rock, the same for infiltration pits around dry wells and infiltration pipes. This only works when its placed in a confined area. Loose they never achieve any compaction.