This advice might show my age and be 'dated' but years ago my DF and my DH rented "push drum rollers" that one fills with water for weight and rolls back and forth across the raked soil.

Thanks for the reply, luckygal. I've actually tried that already, I borrowed my gardener's drum roller and went over the entire yard. But it didn't make much of an impact, as I think it just is not heavy enough to compact 18 inches of dirt. From speaking with my gardener, typically this kind of roller is used to compact a small layer of topsoil and to smooth & even it out a newly installed lawn.

When filling for construction sites here on the TX Gulf coast,, which we do a lot because it is low and flat, the "rule" is fill in 4" lifts. The compaction comes from running over repeatedly with a dozer, Bobcat or the like, bigger projects get bigger equipment (sheep's foot roller, etc.). For landscaping/ planting a top layer of ~4" is left for natural settling and final grading.

Where you have fill beyond 4" I doubt you can do much by hand other than compact the top layer. I believe vibrating plate compactors are limited to abut 2" for good compaction. Where you have 18" I'm not sure even machine compaction would do much. You might call a grading/dozer guy and ask - he should know.

What I do know is that if you plant it unsettled, then later the effects of irrigation/rain will settle it for you, and you will end up with a different grade than you planned. How much, I have no idea. But I would expect it to be greater in the deeper areas, and that would also change your drainage.

Call someone in your area, who knows the local conditions, who knows excavation and grading. You can probably find contacts in the yellow pages.

That soil has a lot of air entrained and one simple method of getting that air out of the soil is to water it, water displaces air. You could get a roller but if your soil sinks that much when you walk on it you probably will have even more trouble trying to roll it.

kimmsr - did you see in the thread above that a roller was previously suggested, that he tried it, and that it didn't work?

I second the thought that it should be compacted in lifts as it's put down. Around here it's done every 6".

You can either bring in some heavy equipment to move it, recompact the base layer and put it back in compacted lifts, or do the best you can and be prepared to fill it and level it later.

kimmsr may have something with the water suggestion. Depending on the type of soil, it may compact better when wet. Although if you try to roll it when saturated, the roller might sink right in and refuse to roll.

You might be screwed, dude. :-]

Thanks for the responses guys. I have been watering the soil every 3rd day and will continue to do so for a couple more weeks. We'll see if that has an impact. I agree with TXEB, I think renting a vibrating plate or other hand tools will only address the top 4-6" of soil. So I am leaning towards renting a Bobcat in about 3 weeks, and driving over the soil to compact it. Hopefully that will compact the soil enough so any future settling is negligible and won't impact the overall look/feel of the lawn. I just hope I have enough clearance to get a bobcat through the side gate of my house. I believe I only have a 45" clearance through the gate.

Hindsight is always 20/20, but there's no way I'm digging up 30 yards of soil just to compact and reinstall it. I told the wife last night I'd prefer to leave it be to ensure proper settling, even if it takes 6 months. Installing grass over this soil too soon will probably bite us in the rear and cost us $$$ later on to grade and re-sod. Needless to say, she wasn't thrilled. lol

If it were me I wouldn't be digging it up either. But before I tired the Bobcat thing I'd talk to a knowledgeable excavator about the possibilities.

I'd go with continued watering, hoping for some good natural rainfall to help out. I built a new 6' x 40' 12" raised island bed over the past winter. We filled it with 6 yards of premium soil, and tried to settle it without compaction as we did. I watered for several weeks and not much settling. Then we got our first good Gulf coast storm system (aka toad strangler). The result after that was a solid 1" settle. Be patient, it will settle.

In the OP you mentioned irrigation and sod. I trust you haven't installed the irrigation yet, which is fortunate. An option you might want to consider for now, while you wait for nature to do the work, is to seed the area with an annual grass. Not sure what grows in your area, but there are several decent annual ryegrasses that could be used. Some local turfgrass experts should be able to guide you. Not only will that give you neat short-term coverage, which will please Ms. Punkaweedus, but the root growth action may help settle the soil. Then in the fall or next spring you can easily get rid of it and finish the project.

BTW - Bobcat has many models, including some with ~ 36" width.

This post was edited by TXEB on Fri, May 10, 13 at 19:03

Very cool!

i really need your help.... is it possible for soil to be compacted less than 6 months?? after using that machine. did you land still sinking?

I doubt the original poster is around since that was 2013. However, I can take a stab at your question. After running a 3000 lb vibrating machine over it, I'm going to guess it was fairly well compacted, because he had also watered it. If you don't use any machinery, it may take longer than 6 months to compact naturally. Perhaps considerably longer, depending upon the type of soil.

I have heavy clay, my house is 25 years old, and the soil is still settling around the foundation to the point where I'm going to have to add some soil to maintain the slope away from the house.

The lesson from this thread was, if you are adding more than 2-4" at a time, and you want a stable compacted surface, such as a lawn, it should be compacted in smaller layers as you go.

I have a few trenches ca. 12-18'' deep, 12'' wide around my house that I'm trying to fill and compact before installing a paver patio. Do you think this can be compacted in lifts using a hand tamper, or do you think I should rent a jumping jack to be on the safe side preventing settling of the patio in the future? Obviously, renting and hauling a jumping jack back and forth is not fun, would like to avoid if possible ;) I will be renting a plate compactor later for the patio base, but it doesn't work in the narrow trenches.

How well you can compact it by hand might depend somewhat on the soil type. Sand, silt or clay? Whether you can handle it manually also depends on how many linear feet of trench you have. I assume you've considered that already. :-]

about 100 feet of trench, soil varies between clay with topsoil-like soil (I guess including some silt) and shale rock. I guess it's really hard to get back the density of the shale rock with disturbed soil. However, most of the trench is less than a foot wide, so even the jumping jack won't work here. I guess the best that can be done here is carefully manually compact the narrow trench in lifts, I use a demolition hammer as it has a smaller surface area than hand compactors and I feel it gives better compaction, and then run a jumping jack and plate compactor on the entire patio area. Any comments?

I have rotary hoed my blok to a depth of 4".The soil is now very light and fluffy and I'm worried that the soil will not have settled enough for the paving which is booked for 3 days time. does anyone have a suggestion for how to settle the soil? Watering?

Paving? Is this a patio, sidewalk or driveway then?

If contractors know what they're doing, they will compact the soil first using mechanical means before putting down substrate (gravel, sand etc.) and finally the pavement.

I would not water this close to having the work done, lest it be soggy for the contractors. Let them handle it.