Installing gravel drive, first timer questions

I have finished excavation of my outbuilding site. Approx 20x35. I did it all with a little 25 horse tractor but I also need to install a gravel drive up to the garage which by my guess is approx 200 feet from the road. I don't care to excavate that much with the tractor. What are my options here?  Can I lay a fabric barrier down to keep rocks from sinking and gravel right over the topsoil?  Do I need to do much more than smooth the drive before getting gravel or do I really need to remove topsoil? What's the typical gravel protocol? 3 4" layers? Is a permeable fabric needed before gravel in my excavation site since it's mostly clay? Thanks in advance!

When we have had gravel driveways installed, first they lay some sort of base directly on the grass.  That is smoothed and then the gravel is dumped and then smoothed.

A really good rock hauler will dump the gravel as he goes down the drive so not much smoothing is needed.

I am sure we have members who know much more about this than I do.

Approaches can vary depending on local geology.   Ask locally about the practices in your area.  In my area, large pieces of gravel first. Then smaller pieces.  

My experience is that topsoil is a giant sponge for water. It will expand when wet, expand even more if it freezes, and shrink as it thaws and/or dries out. This cycle repeats endlessly. A permanent structure built on topsoil never really has a stable foundation.

I think it's preferable to strip off the topsoil and build a foundation on the subsoil. The method  depends on cost and local materials.

Traditionally, coarse rock would be brought in cheap and packed in until it eventually formed a stable base. Crushed gravel, which is more expensive, would be put on top.  

Access roads for industry, though, needed to be fast to install and eventually removable. So, heavy geotextile (not to be confused with hardware store landscape fabric) was laid down and crushed gravel dumped directly on top of it.

I guess costing these two options will lead you to a decision. Since gravel is pricey around here, I would look at geotextile. However, if you find that every local farmer has a rock pile pulled from their fields, you might consider the other approach.

My long winded 2c.

Douglas has it right.
Strip off any top soil, it will not do well at all.
You mentioned "local clay"...
Around here if you have clay base you need to start with 3" or better jagged broken rock.
Followed by smaller  1.5" broken rock.  
Finished with finer crushed rock.
Even after all that, expect to have "problem areas" that will need more rock.
If you have ANY low spots to cross you'll want a culvert.

depends on your immediate finances and soils.  Heavy clay here.  You can reduce the amount of gravel with barrier fabrics but at serious expense.  Cheapest answer short term here is to put 6 inches to a 1 foot down of gravel.   In a few years it will disappear into the ground and then you build it up again.  Last longer the second time.   Mine needs a third run in places but that has taken 38 years.  Most of it is still solid over clay.   Likely geotextiles of some form will require less gravel over time but it is expensive short term.

Material types,
- Clean has no fines, its lumpy rocks. Its hard to drive on and presses into the ground well, it will need top up over time if it keeps settling.
It will continually move around unless contained by a wall or pushed into the soil.
- Minus contains a mixture of fines through to the lumpy rock. The fines help bind the material together a bit like a felt blanket, but will disappear if used on soft ground initially.
Its ideal as an intermediate layer because it does not move around.
After the minus has been pressed in a bit by traffic, shape the road to ensure that water runs off it rather than settle on it and causing sinking.

Depending on the depth of topsoil, if its say 12 inches As a Road builder I would go for this;
- 2-4 inch clean
- then let construction traffic push it in.
- add more if it turns boggy
- if that layer seems to stabilise, add 2 inch minus, it has fines which help bind the mix together.
Eventually you should give the whole road a layer of the sort of thing used locally and then maintain its shape.

I think John C is giving excellent advice. I have seen roads built this way and it works. The trick is to pack in the coarse material, find the soft spots, and pack in more coarse rock to stabilize the base. Only then do you add your top layer.

Mick, I would suggest you do the drive first.
You get the traffic to form the pavement and nobody gets bogged!!!

Hoping it isn't taken as a thread hijack, but I will try to post some of the photos of a similar project here as a way of comparing notes.  We have more of a paddock/mudpit problem that we hope to rectify over the summer.....the worst manifestation of the problem occurring in the spring when the sub-soil is still frozen, but the surface soil has thawed.  I hope to excavate a good portion (6-8 ") of the topsoil/clay and then start with a porous geotextile ( https://www.usfabricsinc.com/products/cowcarpet/ ) as the first layer.  This will be covered by crushed concrete (6-8") recently delivered (uncleaned, see photos) which will be topped off with 'class 5' sand/gravel of the type used on many gravel county roads in our region (Northern Plains, USA).  The problem area blends with the main driveway, a portion of which will get the same treatment, but without the geotextile underneath and without as much excavation.  The whole project will be completed with French drains using the same type of geotextile encircling the pipe *and* the coarse rock.  So this will essentially be a 'burrito' style where both the pipe and the gravel are encircled by the geotextile fabric.  At this point, I'd like to experiment with 'doming' the gravel in the trench upon completion so that it's slightly higher elevation than grade....it probably makes little difference, but I hate the thought of the gravel being below grade and seeing all of that mobilized clay and silt filling in over the top of the gravel.  Will try to update here if it's okay as we make progress through the summer.

John, I read the details of that textile and am surprised.
It looks good, what is the cost of the products compared with rock costs?

John Weiland wrote:Hoping it isn't taken as a thread hijack, but I will try to post some of the photos of a similar project here as a way of comparing notes.  We have more of a paddock/mudpit problem that we hope to rectify over the summer.....the worst manifestation of the problem occurring in the spring when the sub-soil is still frozen, but the surface soil has thawed.  I hope to excavate a good portion (6-8 ") of the topsoil/clay and then start with a porous geotextile ( https://www.usfabricsinc.com/products/cowcarpet/ ) as the first layer.  This will be covered by crushed concrete (6-8") recently delivered (uncleaned, see photos) which will be topped off with 'class 5' sand/gravel of the type used on many gravel county roads in our region (Northern Plains, USA).  The problem area blends with the main driveway, a portion of which will get the same treatment, but without the geotextile underneath and without as much excavation.  The whole project will be completed with French drains using the same type of geotextile encircling the pipe *and* the coarse rock.  So this will essentially be a 'burrito' style where both the pipe and the gravel are encircled by the geotextile fabric.  At this point, I'd like to experiment with 'doming' the gravel in the trench upon completion so that it's slightly higher elevation than grade....it probably makes little difference, but I hate the thought of the gravel being below grade and seeing all of that mobilized clay and silt filling in over the top of the gravel.  Will try to update here if it's okay as we make progress through the summer.

No problem at all.  I had never thought of crushed concrete. When you say 6-8" crushed concrete I assume that's your layer height not the rock size. What size is the concrete?

John C Daley wrote: John, I read the details of that textile and am surprised.
It looks good, what is the cost of the products compared with rock costs?

John, unfortunately I don't have a recent price on the cow carpet and will have to ask my wife what she recalls paying for it.  I did find a discussion on the internet from 2009 that indicated the cost was ~$500.00 for a 15' X 300' roll.  Not sure what it would cost today.

Crushed concrete unfortunately more expensive than I had hoped at 15 yards X $20.00 USD per yard...$300.00 per truck load and I bought 2 loads.  That's pretty close to the cost of class 5 gravel, which does not vary in price too much, but if I had shopped around and played the time factor a bit more (in other words, when big roadway destruction projects in the city are yield large amounts of broken concrete), it could have been much cheaper for the concrete.

Mike Bettis wrote:

No problem at all.  I had never thought of crushed concrete. When you say 6-8" crushed concrete I assume that's your layer height not the rock size. What size is the concrete?

The quarry said it would be considered 1.5-2 inch concrete chunks.  If you shop around, you may find bigger sizes.  From conversations with others, there can be a lot of variation in product and price on these materials.

In Bendigo where I live crushed concrete comes in at about 20 mm minus and once dampened its sets a bit.

I am finding this thread fascinating as there are so many “proper” ways to build a gravel driveway.  I will share mine.

When building my house I went out and marked off the high point from my house to the roadway as the lane for my new driveway.  I used marking spray paint.  A bulldozer then came in and scraped off the topsoil and piled it out of the way by some trees.  My contractor was going to haul it off but I told him “no way” as that was mine.

Next came the gravel.  Actually, it was about 20 tons of limestone dust for a 400’ long driveway.  My contractor told me that he would start with lime dust to really soak up moisture and stiffen the clay beneath.  I would have thought using some type of geo-textile would have been appropriate but he told me that it would prevent the underlying ground from hardening up.  He told me further that he would run heavy vehicles over the driveway to really pack a in after which he would add in 10 tons of 1/2 lime dust, 1/2 gravel about 3/4 inch.  This would get packed in and dressed up a bit at which point my minivan could make the drive fairly easily.  He further told me that the driveway would need to be dressed up again as trucks would continue to pack that gravel into the clay and make ruts and and that a couple more layers of 50:50 gravel/dust would be needed to build up a thick, firm bed (each new layer cost me about $300-$500 dollars if memory serves).

Pickup trucks, lumber trucks, cement trucks and more all packed down that gradually thickening base and it did turn very solid over time.  Rains fell and the driveway turned to slick mud but it didn’t rut deeply and on move-in day, contractors were still working on the house—it looked like it bee hive—and we had 3 weeks with nonstop rain and the driveway was covered again in 2 inches of wet, gloppy mud with little streams that ran down it.  We had a packed moving van (the other house had sold so there was nowhere else to go) but the driveway was such a mess that there was no possibility of getting the moving truck down the driveway without getting stuck.  

I spoke to my contractor who was on-site overseeing the final details.  Previously getting a load of gravel took 3-5 days but one quick phone call and he arranged a load in 1 hour—for $900!  I was over a barrel so I paid it and the new, fresh , “clean” (meaning no lime dust) gravel went down and we could then drive the moving truck down the driveway.

So the point of this whole story is that in my case, my driveway was made by adding several layers, letting them mix together with the subsoil which hardened nicely, packing, grading and repacking and grading again before adding a layer of clean gravel on top.  I had to trench through my driveway at one point and it is thick and solid.  Geo-textiles are interesting but I doubt they can beat the solid character of my driveway layer cake.

But this is just my example and I find it interesting that there are so many ways to build something as simple as a driveway.

Eric

Day one of gravel is done.  I can't say my dump driver was the best.  Got the tailgate stuck and dumped a ton in one spot and then only dumped one side of the garage area but it's not bad for a 200' drive on top of topsoil and a 20x55' garage area on clay.  I have 72 tons of 2 minus coming tomorrow and hoping the box blade manages better.  The 2-4 measured up to 8+ inches and the little tractor didn't like that much.  Here's a pic of the worst spot of the drive.  The whole thing looked like the center until the dump drove over it.  You can't even see these massive stones on the right side of the picture.  But after more grading it's looking ready for the next layer/s.

I just finished up with 2 minus.  So much nicer to work with and its becoming nice and smooth.  I definitely have a soft spot so I'm assuming repairs are in my near future.  Anyway thanks for the help.  I'll keep this post updated in case anyone else runs into these questions.

That looks good

Mike B.,    The driveway looks nice!   Have you had any rains since the last photos?  If so, how is the soft spot holding up to that event?  We are finally past a stretch of 100 F temperatures and I'm getting ready to start gravelling and installing some french drains.  Can't tell you what a treat it was to trailer a 20' long, 15" diameter culvert and 100 ft of coiled 6" diameter draintile pipe during 40 - 50 mph wind gusts!  Good thing gravel back-roads were available for most of the excursion....

One question that arose during my planning was whether it may make more sense in some areas to create walkways out of the french drain run.  In other words, since the french drain will have corrugated pipe surrounded by ~2" crushed concrete and the whole burrito wrapped with geotextile with a final crushed concrete + road gravel covering, what do others think of using stone or concrete pavers on top of the gravel to make a walkway over the trough that is carrying drainage water?

The example below is from this website >>> https://shadygrovelandscapecompany.com/services/landscape-drainage-solutions/drainage-walkways/

I'm far from an expert but as a foot path (not 4 wheelers)  I think it is a great idea!

An additional question on an issue that seems relevant to this thread.  As work continues on our remediation of driveway and walkway structures in very soft clay loam soil, I just replaced a culvert that is crucial for draining an area we wish to have more firm and dry.  The exceedingly crude drawing below illustrates a cross section of the driveway going from the main drive to the work-place site we wish to have more consistently dry.  It looks like a standard culvert job with a lower ditch trough on either side of the graveled driveway through which the culvert runs.  The problem is that there is no way to stabilize the banks of the ditchwork.....and I'm resigned to periodic dredgework to keep the ditches in moderately good shape.  But after heavy rains, silt and mud can settle in the culvert.  Indeed, the newly installed 15" diameter culvert replaces a 12" one that I removed---and which was completely clogged with mud.

I've seen one video by a person demonstrating how a bucket/sump-pit system positioned at the *downstream* mouth of the flow through the culvert allows silt/mud to settle into the pit and can be removed annually so that the efflux side does not accumulate mud that might block the flow and allow settling within the culvert pipe.  Yet I'm wondering about the concept of the "fuel bowl" on many tractors that is placed, often with a filter, in-line with the fuel intake and positioned *before* the carburator/fuel injection system.  Would this concept not also apply here....with placing a 'settling pit' on the intake side of the culvert?   Perhaps on both sides??  The proposed pits are shown as the dotted-line rectangles in the image below.  Advice on this issue much welcomed!....

My home's builder(1999) built my house on a tract adjacent to his family's 5 acres by hacking out 1 acre for his mother in law. He then divorced the wife and mommy-in-law moved in with her to help w/the kids. I don't know if THAT'S why he built my gravel driveway going straight up a hill at about a 28˚ grade. I've lived here almost 4 yrs and the UPS truck (not as bad due to dual rear wheels) and the FedEx trucks (no dual rear wheels, NOT 4x4, and driven by idiots under 30) that just accelerate when their tires spin, have gullied out my lower 2/3 of a 90' driveway down (top 8' are flat and tight) to the dirt--a sandy clay loam typical in the Blue Ridge Mountains of far western NC. I'm going to have to get a grader to come in an scrape the driveway bed before I lay any new gravel. However, I'm not planning on watching the gravel wash out every time we get a good soaking 2-4" of rain--at least 5 or 6 times every year. So I've researched and discovered recycled hard plastic grids (bear 40 tons per sq. meter) that come in various sizes. I first found a great US product called Diamond Grid that they even use for Mine Roads, but the calls to their distributors near me (Atlanta & Mississippi) reveal that nobody stocks the product due to poor sales motility. The next-best so far seem to be Hebden X Grids--made in the UK, and I'm unable to find a US distributor yet. I emailed them, and I'm waiting for a response. Their grids are 1 meter square and interlock. If I get 50 I can underlay my gravel (2 grids) 6'6" wide, by 81.25' long (25 grids). With landscaping cloth laid underneath, and 10" J-pegs anchoring the grids, I can gravel in 1/2" to 3/4" fines with some dust, compact with a vibrator or a small Road Roller and I should be golden. Obviously, I'm laying my plan out here for wiser, more experienced heads to give me an enlightenment if they think I need it. What do y'all think of my plan?

Hi Russell ,

Welcome to Permies.

Russell Grayson wrote:My home's builder(1999) built my house on a tract adjacent to his family's 5 acres by hacking out 1 acre for his mother in law. He then divorced the wife and mommy-in-law moved in with her to help w/the kids. I don't know if THAT'S why he built my gravel driveway going straight up a hill at about a 28˚ grade. I've lived here almost 4 yrs and the UPS truck (not as bad due to dual rear wheels) and the FedEx trucks (no dual rear wheels, NOT 4x4, and driven by idiots under 30) that just accelerate when their tires spin, have gullied out my lower 2/3 of a 90' driveway down (top 8' are flat and tight) to the dirt--a sandy clay loam typical in the Blue Ridge Mountains of far western NC. I'm going to have to get a grader to come in an scrape the driveway bed before I lay any new gravel. However, I'm not planning on watching the gravel wash out every time we get a good soaking 2-4" of rain--at least 5 or 6 times every year. So I've researched and discovered recycled hard plastic grids (bear 40 tons per sq. meter) that come in various sizes. I first found a great US product called Diamond Grid that they even use for Mine Roads, but the calls to their distributors near me (Atlanta & Mississippi) reveal that nobody stocks the product due to poor sales motility. The next-best so far seem to be Hebden X Grids--made in the UK, and I'm unable to find a US distributor yet. I emailed them, and I'm waiting for a response. Their grids are 1 meter square and interlock. If I get 50 I can underlay my gravel (2 grids) 6'6" wide, by 81.25' long (25 grids). With landscaping cloth laid underneath, and 10" J-pegs anchoring the grids, I can gravel in 1/2" to 3/4" fines with some dust, compact with a vibrator or a small Road Roller and I should be golden. Obviously, I'm laying my plan out here for wiser, more experienced heads to give me an enlightenment if they think I need it. What do y'all think of my plan?

Wellllll...Best laid plans, etc: The Diamond Grids are still something I'm looking for, because the Brits wrote back (TWO nice letters from two nice people) saying "sorry, but this is closed-loop recycling: we only use recycled UK plastic and we keep it here in the UK only. We won't ship it out of the UK; we would expect payment in Sterling, not dollars because we aren't set up to take foreign currencies (ever hear of PayPal?) and we only deliver to UK addresses." SO THAT thought, while a good one, is a dead end. I found a Chinese company, but I'm REALLY trying to avoid that route. I just don't trust any Chinese made products. In 10 years, I'll find out that they put nuclear waste in them or something...The search continues. Fu** it. I need time to save up the bucks anyway, so I can save as I search, and I'll update as I go along. Whe I finally get my ducks ina row (quack, quack) I'll post progress pics at every stage of the re-build of my driveway.

Russell Grayson wrote:

Russell Grayson wrote:My home's builder(1999) built my house on a tract adjacent to his family's 5 acres by hacking out 1 acre for his mother in law. He then divorced the wife and mommy-in-law moved in with her to help w/the kids. I don't know if THAT'S why he built my gravel driveway going straight up a hill at about a 28˚ grade. I've lived here almost 4 yrs and the UPS truck (not as bad due to dual rear wheels) and the FedEx trucks (no dual rear wheels, NOT 4x4, and driven by idiots under 30) that just accelerate when their tires spin, have gullied out my lower 2/3 of a 90' driveway down (top 8' are flat and tight) to the dirt--a sandy clay loam typical in the Blue Ridge Mountains of far western NC. I'm going to have to get a grader to come in an scrape the driveway bed before I lay any new gravel. However, I'm not planning on watching the gravel wash out every time we get a good soaking 2-4" of rain--at least 5 or 6 times every year. So I've researched and discovered recycled hard plastic grids (bear 40 tons per sq. meter) that come in various sizes. I first found a great US product called Diamond Grid that they even use for Mine Roads, but the calls to their distributors near me (Atlanta & Mississippi) reveal that nobody stocks the product due to poor sales motility. The next-best so far seem to be Hebden X Grids--made in the UK, and I'm unable to find a US distributor yet. I emailed them, and I'm waiting for a response. Their grids are 1 meter square and interlock. If I get 50 I can underlay my gravel (2 grids) 6'6" wide, by 81.25' long (25 grids). With landscaping cloth laid underneath, and 10" J-pegs anchoring the grids, I can gravel in 1/2" to 3/4" fines with some dust, compact with a vibrator or a small Road Roller and I should be golden. Obviously, I'm laying my plan out here for wiser, more experienced heads to give me an enlightenment if they think I need it. What do y'all think of my plan?

Wellllll...Best laid plans, etc: The Diamond Grids are still something I'm looking for, because the Brits wrote back (TWO nice letters from two nice people) saying "sorry, but this is closed-loop recycling: we only use recycled UK plastic and we keep it here in the UK only. We won't ship it out of the UK; we would expect payment in Sterling, not dollars because we aren't set up to take foreign currencies (ever hear of PayPal?) and we only deliver to UK addresses." SO THAT thought, while a good one, is a dead end. I found a Chinese company, but I'm REALLY trying to avoid that route. I just don't trust any Chinese made products. In 10 years, I'll find out that they put nuclear waste in them or something...The search continues. Fu** it. I need time to save up the bucks anyway, so I can save as I search, and I'll update as I go along. When I finally get my ducks in a row (quack, quack) I'll post progress pics at every stage of the re-build of my driveway.

I've discovered a flexible PVC grid that I can buy on Amazon if need be, but it seems as though my intuition about using a gravel grid for the foundational layer are right on the mark: https://pavingfinder.com/expert-advice/gravel-driveway-on-a-slope/

I'm not an expert on gravel roads, but what is your drainage situation? On such a slope where you are seeing gravel washing out, is there an opportunity for culverts or other water management systems to try and deal with washouts? Not sure if that is something you could plan in if you are considering putting in geotiles.

Timothy Norton wrote:I'm not an expert on gravel roads, but what is your drainage situation? On such a slope where you are seeing gravel washing out, is there an opportunity for culverts or other water management systems to try and deal with washouts? Not sure if that is something you could plan in if you are considering putting in geotiles.

Thanks for the note, Timothy. My only washout issue is in the bottom 15 feet of the driveway, where the water has picked up some steam and some gravel. If I'm using GeoGrids I'm not even going to bother with a French Drain=seems like a waste of time since I'm only experiencing surface movement of gravel.

Russell Grayson wrote:

Timothy Norton wrote:I'm not an expert on gravel roads, but what is your drainage situation? On such a slope where you are seeing gravel washing out, is there an opportunity for culverts or other water management systems to try and deal with washouts? Not sure if that is something you could plan in if you are considering putting in geotiles.

Thanks for the note, Timothy. My only washout issue is in the bottom 15 feet of the driveway, where the water has picked up some steam and some gravel. If I'm using GeoGrids I'm not even going to bother with a French Drain=seems like a waste of time since I'm only experiencing surface movement of gravel.

Looks like I might be using THIS product eventually. It's readily available. but it's flexible not rigid, so I'll only use it if I can't find a rigid option before I redo the driveway: https://rutguard.com/

Here is Bob Vila, on how to make a great gravel driveway:
https://www.bobvila.com/articles/how-to-make-a-gravel-driveway/

The major cost of stone is the transportation. Like everything else over the past four years, the prices have skyrocketed. I used to get 20 tons of SB2 (I think it stands for "Stone Base 2", which is 2" limestone with fines included which help it pack down) for under $300. Now, it is about $500, give or take. This is in NW Arkansas. SB2 is a finish for a gravel road, and is usually underlayed with what is commonly called "red dirt". This is a cherty, clay-like soil and is cheaper than the limestone grades but is still heavy and expensive to haul. Topsoil is usually removed first, to keep the road from "pumping". This is a situation where water seeps up from the base when put under pressure, which is not good. So, I would recommend removing the topsoil if you are going to invest the $$ in stone. Most excavators resist requests to skim the topsoil (it is somewhat time consuming) so that this precious, ancient, resource can be set aside for growing food. Don't give in. I see the mixing of topsoil with subsoil as a Type One Error. Also, the art of slowly off-loading the stone in the path of the planned roadway, as the dump truck creeps along, is called "tail-gating" around here. It might help to refer to it this way to save MUCH time spreading the stone where you want it to be.  

I just had two loads of road base as barney described, limestone with fines, which I assume is small crushed rock/rock dust.

I paid the guy who delivered the road base to spread it several hundred feet $1000.00.  Well worth the now fix driveway.

Plan on maintenance:  Eventually depressions will develop  that hold water.  This lubricates the gravel and car tires splash the gravel out making it deeper.  Adding more gravel will only splash out more making the hole deeper.  The solution is to mix clay in the gravel to keep the water out and fill to the level that rain runs off rather than soak in.  Ballast rock and gravel support weight but filled with water give under weight and when dry can also be scattered.  You probably don't want to use asphalt to bind them together but clay can do a good job of binding, filling water permeable voids, and resisting water intrusion.

Gravel comes from somewhere, and is often from natural sources, so has effects. Demolition waste is also something that shouldn't be, not in the quantities currently available: buildings should be used, looked after, maintained, repurposed - standard pyramid of recycling - before careful dismantling and reuse of components.
Others have mentioned transport. Have words with your local skip supplier?
On site, gravel travels. It can walk out of your drive onto the road, or get itself into adjacent areas of your site. If you haven't already got gravel in your soil, it'll start interfering with your spadework. If you choose to get rid, it'll be contaminated with soil.
Most gravel is a pig to cycle on. Even some cyclable routes in our local park were a problem - sand particles got picked up by my front tyre and sprayed onto the cables running under my bottom bracket, causing them to wear out.
Of course, there are issues with other materials!