Building up Slope w/ Stone before Concrete

[MMH]

I have a sloped parking area that I want to build up w/ stone before pouring some concrete. The area is 50' by 50'. One of the four corners slopes away significantly - 30". Can I build up w/ stone - B3 (1.5" to 3" stone size)? If I do, will I have to compact as I build up?

 

[greasemonkeyok]

Others can address the initial construction, but you will also need to address the long-term effects of water drainage and erosion on the rocks.

 

[ultrarunner]

A lot of the construction where I live is on sloped sites.

I have seen low areas brought up in compacted lifts...

More common is to pour a perimeter foundation, fill the low area with compacted aggregate and then cap it with concrete tied in and reinforced with rebar.

Everything depends on your soil for a design that is optimal for the conditions.

 

[flusher]

A lot of the construction where I live is on sloped sites.

I have seen low areas brought up in compacted lifts...

More common is to pour a perimeter foundation, fill the low area with compacted aggregate and then cap it with concrete tied in and reinforced with rebar.

Everything depends on your soil for a design that is optimal for the conditions.

Yep, the perimeter foundation is the way to go. Otherwise there's always the worry about the fill material shifting under the slab. 30" is more than I'd be comfortable with. The low corner on the 24 x 42 ft slab under my shop is about 15" down. No fill used. The slab is on undisturbed soil. I just had more concrete poured to fix the problem. It's cheaper that way rather than messing around with compacted fill, IHMO.

 

[ultrarunner]

The house next door had almost a 48" low corner under the garage...

The owner/builder was first planning to fill it and then decided to make it a mini storage area for his mower and garden supplies.

I is concrete on 3 sides plus the ceiling... maybe 6' x 8' x 6' high

 

[Obed]

Make sure you compact the fill completely before pouring concrete or the fill will settle and the concrete surface will crack very badly. Parts of the concrete slab could even sink making a unsitely mess. In our area, you can rent a walk behind compactor for about $50/day. Driving over the fill with a Bobcat isn't good enough to compact it. Some contractors will tell you that compacting the rock with a Bobcat will work - that's a contractor you want to avoid.

I would also make sure there is a way for any water that gets in the filled area to be able to drain out from under the slab. In other words, don't end up with a hole filled in with gravel with no outlet for drainage. That spot will collect water, freeze and thaw, and potentially cause the slab to sink if water can't drain out of the rock.

Obed

 

[Cat_Driver]

You might want to look at a small retaining wall to stop any future erosion. If it all stays at a slope you will get run off that could erode at the end of the slope no matter what your base is.