How much movement is allowable in your stone base?

[slowTA]

I'm assuming this shouldn't happen, but did I fix it by just stepping on the soft parts and leveling it out?

I will say that this is on the wet side of my garage, it faces up hill and I don't have gutters yet (to be installed next week) and it rained a ton last night.

 

[outdoorspace]

Doesn't look like many "fines" in that rock. The fines are needed to lock everything together so it compacts.

When I did my shop I drove over it a few times with the tractor in-between rains, and I just stomped on it near the edges. It ended up hard as a rock. I used "ABC" (aka Crush & run) gravel on mine.

 

[ConCretin]

Stone doesn't compact very much volume wise. Is it possible that the soil below is saturated allowing the stone to displace it. If so, you definitely want to correct the situation by draining or diverting the water. This is especially true if that is a base for a slab on grade.

 

[Slowgsr]

Clear gravel like that won't lock together. Doesn't need too that's why they use it. 3/4 crusher run packs tight with a plate but its more work. That's why they use clear, less work.

Is the subgrade virgin & dry?

 

[slowTA]

Here is what I started off with and what it turned into. Cut on one side and fill the other, no fill was brought in.

There is some moisture under the vapor barrier, but I don't think that's something I'll need to worry about now.

 

[slowTA]

With the building up and after some rain, you can see the dirt settled around the posts. Most of them were like this.

 

[TommyK]

If the subgrade is pumping under just foot traffic you need to let it dry out until it stabilizes again which may take several days of dry weather. When it stabilizes I would proof roll the crushed stone and re-grade as necessary before pouring concrete. The settlement around the posts indicates a lack of compaction which may have contributed to the subgrade instability.

 

[theoldwizard1]

My guess is there is now "cloth" below that rock. It will continue to sink in, year after year. Not much, but it will sink.

Was it compacted when the rock was laid ? Sharp (crushed from larger rock/stone) is good. Mixed with smaller gravel and fine and power compacted on top of HD landscape cloth is best.

 

[slowTA]

There was nothing put down before the stone and there was no compaction of any kind.

 

[slowTA]

I read the quote again and the stone spec'd is #5 Certified Drain Stone.