Building up grade questions

[05wrangler]

I have been looking into starting my pole barn build soon. I have a guy that gave me a price to build up the grade as my land slopes pretty quickly in the back. I need to bring the front up 1 foot and the back up 3 feet ( total fall is absolutely 2 feet, but getting the front up to ensure no water comes in). So I am building a 24 wide, 30 foot deep structure. He says he will slope the stone (I'm not sure what type) 2 feet out, so basically I'll be looking at 28x34 foot print. He also says he won't need to compact it. What do you guys think about all this. Here is what I'm thinking please correct me if I'm wrong.

1- remove top soil underneath
2- compact in 4 inch lifts.

I'm also a little nervous about the 2 foot slope being ok. I'm wondering if it would be easier to just dig footing and lay block and stick build. I'm open to any ideas here guys as I would really like to get it built. Also, the floor will be 6-8 inch think.

Thanks for your time and help!

Sent from my SAMSUNG-SM-G870A using The Garage Journal mobile app

 

[dave_dj1]

What kind of stone would be one question. Another would be why a foot in the front? 2" would be enough. I would do as little as possible.
Anyway you can either swap the orientation so it's not as deep as it is wide? that would help some.

 

[05wrangler]

I'm working on finding out what stone. I need all the depth I can get so I can pull a full size truck into the garage with a little wiggle room.

 

[rzims]

I'm assuming "stone" is Class II base rock under the concrete. Usually that goes down in lifts and gets compacted. A lot of people that do transporting and grading don't have the equipment for that so they lay it down and grade it with a box scraper/blade and call it good.

Obviously, not having a stable (well compacted) base can lead to all sorts of settling issues which in turn leads to concrete cracking/failures...

I wouldn't take any shortcuts on the subbase...

 

[theoldwizard1]

You need a retaining wall in the back ! This will NOT BE CHEAP !! You need deadman/tie backs into the hill (under the floor) AND a proper foundation. The back fill behind it should be gravel to within 1' of the finish grade. Also drainage behind this wall is critical.

"You can pay me now, or you can pay me later" applies here !!

 

[05wrangler]

You need a retaining wall in the back ! This will NOT BE CHEAP !! You need deadman/tie backs into the hill (under the floor) AND a proper foundation. The back fill behind it should be gravel to within 1' of the finish grade. Also drainage behind this wall is critical.

"You can pay me now, or you can pay me later" applies here !!

This makes stick building sound better

 

[ConCretin]

You don’t need a retaining wall but you do need more than a two foot slope to properly compact three feet of material in lifts. I’d want to see at least a 45 degree slope and preferably more.

Edit; I just noticed that you are using stone for your base. There are those who believe that stone doesn't require compaction. In fact, I've placed large foundations on deep fills of un-compacted stone. Having said that, I'd still be more comfortable if the stone were placed in lifts with a compactor run over it.

With regard to your slab thickness, 6 or 8 inches is way overkill and a waste of money. Focus on a properly constructed base and 4 or 5 inches is fine. A few extra inches of concrete won’t make up for an inadequate base.

There are pros and cons to a pole structure but your site conditions can be adapted to any foundation system.

 

[6768rogues]

I would do the following:
Remove topsoil, it will get squishy.
Use #1 crusher run, concrete washout chips or engineered fill, compacted in 6" lifts.
Slope the sides away at a 45 degree angle.
Use 4 to 5 inches of 4000# air entrained concrete with fiber mesh and #4 bars every 2 feet in both directions.
Or pay to have an engineer design the most cost effective base that will work.

 

[WhiffySpark]

Sounds to me like you have an old school contractor who knows what works in your area.

If I tell you how much that retaining wall would cost you would quickly figure something else out

 

[05wrangler]

Im not relying on the slab thickness to make up for any shortcuts in grade work, I want 6 to 8 because of a lift and use of a fork truck with loads on it. I my look at at least getting a price to go stick built. All I need is the foundation work and block laid. And slab poured. I will self preform the rest. Same goes for if I go with a pole barn.

 

[EOC_Jason]

Hire a geotechnical engineer...

 

[Radix2]

Do you have the space to grade up to the building at a lower slope with soil after building the compacted base? 45 degrees is ok for the rock, but you would want a gentle slope of soil over it if possible.

On that size of building and assuming you want to finish it, i'd highly suggest stick built.

Even if just a slab, good practice is to run the thick edges down to native undusturbed grade.

 

[ConCretin]

Im not relying on the slab thickness to make up for any shortcuts in grade work, I want 6 to 8 because of a lift and use of a fork truck with loads on it.

A 4" slab is adequate for your use if the base is properly constructed. An 8" slab might not be if your base isn't built properly. Your slab is a non structural work surface that imparts the loads placed on it to the soils below. I'm all for overkill. Just pointing out that you could save some money that could go towards a nice epoxy floor or that lift.

 

[05wrangler]

A 4" slab is adequate for your use if the base is properly constructed. An 8" slab might not be if your base isn't built properly. Your slab is a non structural work surface that imparts the loads placed on it to the soils below. I'm all for overkill. Just pointing out that you could save some money that could go towards a nice epoxy floor or that lift. [emoji481]

I like what your saying here lol

Sent from my SAMSUNG-SM-G870A using The Garage Journal mobile app