Gravely grappling with gravel grandeur

August 10, 2010 9:37 AM

What size gravel do I need to (a) top up my driveway and (b) fill in a trench?

The driveway is pretty tired, and becoming more dandelion than gravel, so it's time I topped it up -- and I also recently had to dig out around a big (18' x 18') shed to lift it up with some farm jacks and re-set it on fresh concrete blocks.

Now I've got a tired driveway, and also some 18" deep trenches around two sides of the shed.

I'm getting some quotes on driveway gravel, and it seems that the 0-3/4" is much cheaper than the 3/4"-1.5" based on early results. Like $150 vs. $400 for five tons.

The driveway is at the top of the hill; the shed, at the bottom. I am not the sort to lie awake at night worrying about whether or not my driveway is pretty, merely functional. Drainage for the shed would be an asset, though.

posted by Shepherd to Home & Garden (11 answers total)

Best answer: For a functional driveway you want either an unwashed pit run (cheapest but will include some large rocks IE: several inches across) or a 3/4 minus crushed gravel. Both of these products include a range of particle sizes so that the drive way packs hard there by resisting rutting and pot holes. You can use the same thing around your shed but it won't drain incredibly well. Preferred would be a drain rock which will have a narrow range of washed gravel that won't compact.
posted by Mitheral at 9:53 AM on August 10, 2010

Best answer: 3/4- crush is the most common driveway gravel. As Mitheral said, it compacts down and resists ruts, potholes, and rolling away down your slope.
posted by elsietheeel at 9:58 AM on August 10, 2010

Uh, sorry. That would be the cheap stuff. The 0-3/4". It's called generally called "three-quarter minus crushed rock" because the particles are 3/4" or less.
posted by elsietheeel at 10:01 AM on August 10, 2010

Best answer: #57 stone is a good size for drainage. You still probably want to wrap it in filter fabric to prevent the migration of fine soil particles into the stone. For driveways and structural fill we mostly use CR6. It's cheap and usually pretty well graded.

Also, have you considered pouring proper footers for your shed rather than using concrete blocks?
posted by electroboy at 11:11 AM on August 10, 2010

Looks like CR6 (also known as "crusher run") and 3/4 crush is pretty similar. You might also be able to get RC6, which is recycled concrete. Should be a lot cheaper, although if you have color preferences you'd probably be out of luck.
posted by electroboy at 12:25 PM on August 10, 2010

electroboy writes "Also, have you considered pouring proper footers for your shed rather than using concrete blocks?"

Be aware that in a lot of places this turns a delightfully informal "temporary" building into a "permanent" building which can include a world of regulatory hurt.
posted by Mitheral at 7:43 PM on August 10, 2010

Also, in a lot of soils doing the "proper" footers is a really bad idea, because it turns a temporary building into a permanent nuisance.

The local "rock place" sells what they call "road mix" -- it's 3/4 plus a lot of clay particulate that forms a decent concrete.
posted by SpecialK at 9:07 PM on August 10, 2010

Also, in a lot of soils doing the "proper" footers is a really bad idea, because it turns a temporary building into a permanent nuisance.

Is "soils" a typo? This doesn't make much sense otherwise.
posted by electroboy at 6:46 AM on August 11, 2010

Is "soils" a typo? This doesn't make much sense otherwise.

No, not a typo. Soils as in "types of soil" -- for instance, we have a clay riverbed soil in the area where I live that expands and contracts heavily as the moisture level in the soil varies. West of here, you get into limestone soils -- there are several types. East of here you get into excellent red dirt. All three types have different needs as far as foundation goes, and in clay or mixed clay/sand soils like you have in my local area, it's actually preferable to "float" a framed pier and beam house on the surface of the clay instead of trying to pour footers. If you do pour a foundation and footers, you need to do some remediation to the soil to reduce the expansion and contraction factors before you can pour concrete into it and not expect the concrete to fracture when the clay gets wet and expands, and then collapse when the clay dries out and contracts.
posted by SpecialK at 8:19 AM on August 11, 2010

Texas and parts of the south are fairly unique with regards to expansive/gumbo clays. It's pretty project specific and only a consideration if you live in those areas. Given that the poster appears to be in Canada, it's not really relevant. They'll have more issues with frost heave/foundation depth than anything else.
posted by electroboy at 10:52 AM on August 11, 2010

Response by poster: I considered the permanent footers, but haven't yet done the research on what that would do to the "status" of the shed. As it stands, it made it probably 20 years on the old blocks, and I'm going to pop the floor in a couple of weekends and drop some deck blocks down with 4x4 to attach to the lower joists. I'm not really worried about it.

I'm battling the fact that every rock place around here is French, and they seem to have different terms for everything, but "0-3/4" seems to be working as a descriptor.

Sounds like I'm okay with 3/4- for the driveway, but would be better off with 3/4+ for the trench. I should be able to split-order that, yes?
posted by Shepherd at 6:09 AM on August 12, 2010