How to get this rock floor compacted?...

[brad hays]

I'm trying to even out my dirt/rock garage floor by adding 3-4 in of 1/4" and below limestone fines and mixing/raking in type I / II portland cement into the top 2-3 in. Idea was to use a plate compactor to get it mashed down then sprinkle with water, compact, sprinkle. Well, the small rock mixture with the slippery cement powder doesn't seem to be suitable for a plate compactor as the machine tends to borough down through the substrate spitting it out from the sides, even at it's slowest speed. This is a problem I'm guessing larger rock mixtures don't suffer from. So now I'm left trying to figure out how to get this stuff compacted, I guess by hand? The good news is the rock the machine managed to compact looked fairly good with no gaps. The cement is mixed in thoroughly and fairly deep. Although I'll be watering/misting I'd say gingerly I plan on giving it enough water so it reaches the bottom layers, and keep it damp over the next week as it cures.



My only ideas for compacting so far are either a 8x8 hand tamper or possibly a weighted roller? Any suggestions?

[Tom M King]

It's still compacting it, even if squeezing out to the sides. You just have to keep going over it. It probably has too much water in it for now, being so plastic.

When we have a red clay fill under pavers, that's the way it works too. I never expected that to be the finished surface though.

[Ken Fitzgerald]

It's still compacting it, even if squeezing out to the sides. You just have to keep going over it.

I agree. The one time I used a plate compactor to compact some gravel on top of earth as a base for concrete edgers, I had to keep going back and forth over it until it was finally compacted. It has withstood 25+ years of freezing and thawing since I first did it with no apparent issues.

[brad hays]

Thanks for the encouragement but with the way it was completely working through the substrate down to the original floor there's no way using it would ensure a consistent, or even a flat surface for that matter. Upon thinking on it more these compactors aren't generally used on rocks this size as a surface finisher so maybe it was never destined to work.

Anyhow, I've got myself a 10 x 10 tamper from the big box and now I'm just gonna rake it back even again and go at it that way. After leveling and pounding I'll sprinkle my water like I had planned before. It just won't be as compact as before but since a light packing seems to result in a no gap top I'm hoping this will work.

Any advice going this direction?

[Myk Rian]

Did you use sharp stone, or pea gravel(smooth) ?

[brad hays]

It's sharp limestone 1/4" and below, so there's plenty of sand size elements. Combined with the portland cement it just wouldn't stand compaction with anything motor driven...just too harsh.

So tonight I leveled as best I could, sprinkled water then tamped it all down. For my first floor it's not too bad really...maybe a C+. But the tamping didn't turn out as even a floor as I wanted so now I'm looking to fill in some of the shallow places.

Any advice for any kind of floor leveler that would work on a floor like this that's gonna be kept wet over the next week or so while it cures?

[Thomas McCurnin]

I use "road base" which is a crushed rock designed for this exact purpose. Then decomposed granite as the finished floor surface.

[lowell holmes]

You might visit a tool rental store and see if they can help with a tool.

[Myk Rian]

But the tamping didn't turn out as even a floor as I wanted so now I'm looking to fill in some of the shallow places.

A lawn roller perhaps. That will smooth the surface.

[Ken Combs]

A lawn roller perhaps. That will smooth the surface.

I agree, roller would be a good final step, but a concrete rake, the big wide hoe that us used during pours, would be a good first step to move stuff into the low spots.