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Path: Thin layer of crushed gravel on compact clay?

Posted by jenn 9/19 (My Page) on
Wed, May 18, 11 at 15:24

Still working on the path in our side yard....

Now we're considering just tossing a thin layer of crushed stone/gravel on top of the compacted clay (very compacted, after years of treading) in a strip leading from our patio to the garage. NOTE: I'm not talking about pea gravel, the round stones that don't compact. I'm referring to small crushed gravel about the size of pea gravel and smaller but with sharper edges.

I've seen several photos of paths like this -- they look similar to a well-worn hiking path -- very natural, casual, easy to construct, and inexpensive. The layer of gravel is very thin, maybe 1/4-1/2 inch and in some places the soil shows through. We would edge this path with field stones.

We understand the disadvantages -- weeds allowed to poke through, and gravel possibly tracked in the house -- but the area is easy to hoe and we have a path of DG in the front yard and haven't yet seen it tracked into the house.

Has anyone made a path like this with good long-term results? When we go to the materials yard, what material should we ask for?


Follow-Up Postings:

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RE: Path: Thin layer of crushed gravel on compact clay?

  • Posted by bahia SF Bay Area (My Page) on
    Wed, May 18, 11 at 15:31

If you are actually walking on this in the winter, such a thin layer of crushed rock will get pushed into and mixed with the clay in short order, and simply disappear. There is plenty of information out there on the proper way to install a gravel path under California conditions, why keep insisting on doing it in a way that won't hold up? At least several inches of depth, with an underlay of filter fabric is going to hold up better.


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RE: Path: Thin layer of crushed gravel on compact clay?

  • Posted by jenn 9/19 (My Page) on
    Wed, May 18, 11 at 15:39

Thanks, bahia.

I'm not "insisting" on doing it in a way that won't hold up; I'm posting some ideas and asking questions about them to learn the pros and cons from others' experience. You pointed out a problem I hadn't considered.


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RE: Path: Thin layer of crushed gravel on compact clay?

  • Posted by jenn 9/19 (My Page) on
    Wed, May 18, 11 at 15:42

Bahia: One detail I should mention is that we use this path to push the wheelbarrow or trash barrel (on wheels) from the garage to the backyard, so we want a material that will hold up to the pressure of the wheels without creating grooves. We also would like a path that is not too labor-intensive to build -- since both of us have shoulder and back issues -- but also looks attractive and blends with the surrounding environment. I'm exploring all the options.


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RE: Path: Thin layer of crushed gravel on compact clay?

For a path like this, i think you will really like the look and use of crushed granite. Dont worry, even though it says "granite", it is very inexpensive and common in most material yards. It compacts better than gravel and has a great tan color. Hope this helps!

Here is a link that might be useful: online landscape design


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RE: Path: Thin layer of crushed gravel on compact clay?

I just think you would find that that construction method does not hold up--especially for heavy-ish objects on wheels.The fact that it would be over the compacted clay affects how the path handles water and so the thin layer that you describe will not necessarily compact together properly, as I understand it. So one point might be, if you are just trying to have a path that has some gravel showing here and there and you like the texture combo rather than just hardpacked dirt, it may be that no special kind of gravel is needed because--and I am not an expert here--you have bypassed the construction methods that promote the behavior of DG as packing and interlocking particles.

If you were just aiming for a footpath to avoid mud, I would say that it is possible to make informal stepstone or paver paths with less rather than more preparation than is often recommended--again that is allowing for lower expectations for aesthetics and stability; but for rolling wheelbarrows and garbage cans, you need more width than a step-stone type path.

Maybe it is because I take to heart your proposed dimensions--1/4-1/2 inch thick is not very much! I believe that some apparently well-worn hiking trails actually have additional gravel added over time for this very reason. Plus if you have hiked after a rain and after the park rangers have driven through you will see the ruts with standing water and mud.
One concern I have is that adding the very thin layer may actually change the clay to be more of a weed substrate than before, because now the soil may become more porous and aerated instead of being relatively inhospitable. When you say "easy to hoe," I think, hoeing is so disruptive, it will make it worse, and then how does it end up looking better than just a beaten path?

But what I hear you saying is, you would like the look of a gravel-ish path. So maybe if your expectations for better function are low and you like the aesthetics of a gravel-ly path, it is right for you.

This is a long way of saying I have not made a path like this with good long-term results.


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RE: Path: Thin layer of crushed gravel on compact clay?

We covered a large garden area as bahia described......a layer of fabric and 1 to 1 1/2 inches of 1/4 minus gravel on top of it. Enough water was sprinkled on the stone to wet it and then a compactor was used to 'set' the stone.
That was 3 years ago and it's still looking good. Wheelbarrows, GD's bike, and garden carts have gone across it with no problems.


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RE: Path: Thin layer of crushed gravel on compact clay?

The paths in Gertrude Jekyll's garden are, or used to be, made from a material known as 'hoggins', hoggins is a mixture of clay and small stones that when compacted becomes solid enough for walking with a wheelbarrow. The ground under her garden is sandy. As you already have the clay mixing something like gravel (a non specific that could be crushed granite, crusher run, stone dust etc) could work. If you put it on the top without the geotextile it will mix just by walking on it which contrary to bahia I see as a good thing. Just be warned that drainage will be a problem and that clay expands and shrinks (cracks) depending on moisture.


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RE: Path: Thin layer of crushed gravel on compact clay?

  • Posted by bahia SF Bay Area (My Page) on
    Thu, May 19, 11 at 10:06

Ink, this is one situation where your unfamiliarity with a Mediterreanean Climate limits the usefulness of your advice. We get all our rain in winter, and the path will be unusable after heavy winter rains, and a weedy mess in spring through fall, as the OP intends to use this path if she follows your advice. It will be more clay than gravel if it is used regularly during rainy periods. It would be better to use larger/wider pieces of flagstone to accommodate the trash can and wheelbarrow wheels, set within a sea of gravel if they don't want to sub out the necessary depth for 1.5 to 2 inches of gravel. I'd still recommend the weed fabric as a highly useful feature that keeps the gravel from being lost over time to the sub-base clay, and also helps to minimize deeper rooting weeds,(it won't prevent annual grasses from blowing in and rooting, but does make them easier to pull).


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RE: Path: Thin layer of crushed gravel on compact clay?

I didn't know the location David which is why I mentioned the sandy soil and possible problems with drainage as factors to conider. However I still think that a reasonable (not ideal) path can be made if the geo is eliminated and gravel is added periodically as it mashes into the clay.


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RE: Path: Thin layer of crushed gravel on compact clay?

The ground right around my house is made of clay and irregularly shaped granite rocks about 1" thick and 1-3" on their longest side. It's mostly the granite, with only enough clay to fill in between the granite. (This was how they flattened space to build the house.) It is extremely solid and hard packed, even when it's wet, because of the high ratio of granite to clay. It is not weed resistant, at all, unless it's a spot that is very frequently walked. It's also very hard to dig in because you hit rock before you get even an inch down, and it is not particularly attractive.

I think whether or not your plan will work depends on how soft your clay is when wet. If it's purely clay with only some small gravel the size you describe for the surface of your path mixed in, the small gravel you add will continue to work its way down into the clay but will not create the stable base you want anytime soon, and will need replenishing regularly. The fact that you say it's easy to hoe leads me to think it's mostly clay.

When it's wet, how is it to walk on? Because if it's soft and your feet sink in or slide, your small size gravel will get swallowed by the clay. You need some sort of solid substrate to support the smaller gravel, and clay alone doesn't provide that, no matter how solid it is when it's dry.

If you could create the situation I have around my house, maybe by having some of the clay dug out and mixed as a filler only with larger solid rocks, then put back in and compacted, it would create a solid base you could put your smaller gravel on top of for appearance sake. I know that's not a small and easy job to do yourself, though.

Why not ask the materials yard their recommendation for your path?


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RE: Path: Thin layer of crushed gravel on compact clay?

  • Posted by jenn 9/19 (My Page) on
    Thu, May 19, 11 at 14:55

Thank you all for your very helpful comments; I'm taking all of them into consideration.

The soil along this path seems to drain well even in winters with a lot of rainfall. The soil there isn't the raw sticky type of clay (like Play-Doh) and I don't believe it is particularly soft or slippery when wet. There used to be a thin layer of bark scattered on top and some of it is still there.

I'll take a closer look this weekend, especially after I do some watering of the plants around it, to get a feel for the type of clay and how it will handle this type of path.

Many thanks again...


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RE: Path: Thin layer of crushed gravel on compact clay?

I think this is a good example of a very a site- and condition-dependent question. A "acceptable" result is not actually unimaginable but is not predictable from what can be discerned in an internet post. And jenn, the answer also depends on how much you think you would "lose" by experimenting--that is part of the reason for such caution in saying, heck, yeah, just throw some gravel down, in case that was the very $$ you would need to put toward a more elaborate method or if you then had to dig out more junk to correct it. Whereas some people are fine with trying a quick-and-dirty solution first and re-grouping if they don't like the result. That is an aspect of what I said and ink said about adding more gravel--again, some people would see that as affordable and relatively easy option(like re-mulching a large bed at intervals) whereas others would be annoyed at what they see as constant upkeep.


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RE: Path: Thin layer of crushed gravel on compact clay?

To the OP / Jenn

We have two paths like that at our own home, and did one at our last Beaverton home. First time I used fabric beneath and should have skipped it since its often a pain.

The fabric is sensible under 2, 3 or 4 inches sometimes. But the gravel you probably want to use (1/4 - 10 washed) is sort of sloshy when laid deeper than one inch. If an inch is laid, the fabrics frequently show their ugly mugs.

Our paths need but a little hand weeding lately, like 1/2 hour twice per year. I prefer to lay 3/4 inch to an inch and just topdress if the soil starts to push through.

Decomposed granite was the worst material we ever used (Medford / Applegate Valley) in close proximity to a home.

We have a clay-like soil. Not sure what you have. With every extra coat of gravel, the surface becomes firmer. So far, we have not had foot prints sink in, nor has my wheelbarrow pressed wheel ruts when I move mulch, pavers, etc..

1/4 minus probably packs better, but I like the multi-colors in some 1/4 - 10 grave (comparable to pea gravel colors).

About all I can share is what we tried and how it has worked for us in this location.

M. D. Vaden


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