Putting in a gravel driveway

[future_vision]

A culvert and ditching would assure good drainage. A wide ditch or swale would be easy to maintain.
I would put in at least a 16" culvert, not because of flow but because it will silt up and fill up some over the years and the larger culvert will go longer between cleanings and is actually usually a bit easier to clean out.
Also the double wall culverts with the smooth insides are much better then the single wall corrugated things.

How far below the surface of the finished driveway should the to of the culvert be?

 

[paulsharvey]

How far below the surface of the finished driveway should the to of the culvert be?

12" Minimum coverage, over the top of the pipe. So, if you are placing 12" of base rock, at a min you want the full thickness over the pipe. It looks like that will not be an issue. If you are placing the pipe in that dip area; what I would do, I would place the pipe, and back fill 12" Over the top, before placing the 12" of base rock; for a total of 24" coverage, and that will take a significant chunk out of your dip. Keep in mind, that pipe is going to need to be absolutely 24 ft long, and depending on how they sell them locally; I'd buy a 30 or 32 ft long one. Your going to want a 4:1 maybe get away with a 3:1 slope on that embankment fill, if we are skipping the retaining wall idea.

So, let's say we use a 15" pipe, +12" fill, +12" base=3'6" we have picked the road surface up from the existing ground level at the dip. Nope, it's not the fill 6-7 ft, but it's half of it, and that will IMO be good enough

 

[Midniteoyl]

Yep. Gave them what I was looking for. This is the full quote:

What I can tell you is if your driveway is 600'Lx12'W and your garage area is 38'Lx55'W and you want 1' Depth of road base (4"minus bank run gravel) you would need 412CY of material.
412cy (4" minus bank run gravel) x $15.00 = $6,180.00
Delivery = 23 loads x $115.00 = $2,645.00
TOTAL = $8,825.00

That's a good price. Around here, just using the truck by truck pricing not the 'whole job' quote, it would be ~$13200 delivered direct from the quarry. Add $2500 if using one of the 'gravel guys'.

 

[future_vision]

12" Minimum coverage, over the top of the pipe. So, if you are placing 12" of base rock, at a min you want the full thickness over the pipe. It looks like that will not be an issue. If you are placing the pipe in that dip area; what I would do, I would place the pipe, and back fill 12" Over the top, before placing the 12" of base rock; for a total of 24" coverage, and that will take a significant chunk out of your dip. Keep in mind, that pipe is going to need to be absolutely 24 ft long, and depending on how they sell them locally; I'd buy a 30 or 32 ft long one. Your going to want a 4:1 maybe get away with a 3:1 slope on that embankment fill, if we are skipping the retaining wall idea.

So, let's say we use a 15" pipe, +12" fill, +12" base=3'6" we have picked the road surface up from the existing ground level at the dip. Nope, it's not the fill 6-7 ft, but it's half of it, and that will IMO be good enough

Thanks. What would you back fill with in this scenario? I do have some non-organic material that I could use. Would you back fill some of the dip first and then the pipe followed by more fill and then the the bank run gravel?

 

[future_vision]

That's a good price. Around here, just using the truck by truck pricing not the 'whole job' quote, it would be ~$13200 delivered direct from the quarry. Add $2500 if using one of the 'gravel guys'.

Good to hear. I've been looking into renting a dump truck and pick the stuff up myself. But 23 loads is quite a few to get done in one day. If I could get 23 loads done that would probably save me $1300-$1500 if the rental is $800/day. Of course it would be less than 23 loads is I don't go with 12" of base layer.

 

[sixdogs]

Lots of comments and opinions so let me offer one thought everyone will agree with. Spend the money and put a great base in. It can be some rocks and then lots of bank run gravel and make it deep and wider than you think.

A good--no great--bulldozer guy makes a huge difference and knows what to do. We did three gravel drives in Maine. I did the first, had help on the second and got a great dozer guy for the third. That was the best.

Oh. don't drive down the center all the time but drive off-center to avoid ruts. And a rock rake in the spring will do a great job leveling things while a blade will create more problems than you want.

 

[future_vision]

Lots of comments and opinions so let me offer one thought everyone will agree with. Spend the money and put a great base in. It can be some rocks and then lots of bank run gravel and make it deep and wider than you think.

A good--no great--bulldozer guy makes a huge difference and knows what to do. We did three gravel drives in Maine. I did the first, had help on the second and got a great dozer guy for the third. That was the best.

Oh. don't drive down the center all the time but drive off-center to avoid ruts. And a rock rake in the spring will do a great job leveling things while a blade will create more problems than you want.

What were the issues you had doing it yourself? I've got nearly the entire drive, minus the dip area, level down to the non-organics. All measured with a rotary laser. I am curious what a professional would do differently?

 

[paulsharvey]

Thanks. What would you back fill with in this scenario? I do have some non-organic material that I could use. Would you back fill some of the dip first and then the pipe followed by more fill and then the the bank run gravel?

I would set the pipe at the bottom, add your no organic material to the top the pipe, compacting as you go. Then do your road bed.

 

[Too many Kubotas]

12" Minimum coverage, over the top of the pipe. So, if you are placing 12" of base rock, at a min you want the full thickness over the pipe.

Uh, oh. That sounds like the little 12" culvert I just lengthened won't make it.

Well, I'm not worried. With a few culverts like that, all of which have survived so far, it might live.

After all, the 24" one that has supported dozens of fully loaded end dumps and other machinery over the years is alive and well, with about the same amount of fill above it.

 

[paulsharvey]

Uh, oh. That sounds like the little 12" culvert I just lengthened won't make it.View attachment 980854

Well, I'm not worried. With a few culverts like that, all of which have survived so far, it might live.

After all, the 24" one that has supported dozens of fully loaded end dumps and other machinery over the years is alive and well, with about the same amount of fill above it.

Not saying less coverage will immediately crush, but 12" of coverage is generally spec'd by any public works/road department, and is a good guideline. Our OP has the ability to get the coverage, and frankly it helps his dip problem, so coverage is his friend.

 

[Too many Kubotas]

True, in his case it helps. For me, I have to go by what depth the ditch is (pictured was a drain) and ideally I can keep the level uniform on both sides of it.

That described 24" culvert does have a somewhat substantial hump over it and bridges the main irrigation ditch. Sure, I could easily add some dirt to that one, but it's already a bit close to touching some trailer's landing gear.

But since that's not a drive I regularly plow, it's fine as is.

 

[dodge man]

The culvert needs to go in at the elevation the low area is. Then if that’s not deep enough build the road up high over it to get your depth of cover.

 

[future_vision]

I would set the pipe at the bottom, add your no organic material to the top the pipe, compacting as you go. Then do your road bed.

I would think that is too low though. If the bottom of that dip is 7' lower than level with the rest of the driveway, and I already have material to either side, I would think I'd need to be at least a couple feet higher wouldn't I to keep the culvert fro being buried? Or maybe you are thinking I need to remove material on both sides to create a path for the water?

 

[LouNY]

Your culvert should be at the low point of it's installation point, otherwise it will trap water and saturate your fill site and driveway.
You should contour out a drain swale or ditch and put the culvert in that run.

You are need a long culvert, I wouldn't be surprised if you need a thirty or even forty footer (2 twenties).

 

[ruffdog]

Exchanged emails with a local pit and they gave me a quote for 1' of -4 bank run gravel. Isn't 1' a bit much?

The guy that did my drive used a 6-way dozer and dug out 1.5' of soil, then it was filled with 4" crushed rock. He said the odd shapes of crushed is way better than rounded rock for "locking together". He then used his big vibrating roller to get the base tight. Crusher run topped it off and was rolled. If the base isn't sufficient, you will be in trouble in the spring when the frost comes out.

 

[paulsharvey]

I would think that is too low though. If the bottom of that dip is 7' lower than level with the rest of the driveway, and I already have material to either side, I would think I'd need to be at least a couple feet higher wouldn't I to keep the culvert fro being buried? Or maybe you are thinking I need to remove material on both sides to create a path for the water?

It's all in what you want. I really think taking away 3-4 ft of your 7 ft dip will make a plenty good drive, without the added expense/effort/maintenance issues of filling the whole 7 ft. However, if that is what you want, no dip at all, flat, yes, you'll still need to place something like 4 ft of fill over the pipe. Just keep in mind the slope, or retaining walls. I would definitely set the pipe at the bottom; we aren't trying to dam water at all.

I'm also a cheap ass; so, my thought, if it was me, 15" pipe at bottom, 12" fill, maybe upto 24" fill; our 12" base, and see what you think; if unhappy, pull the base off and add more clean fill. Part of my worry is cost, but also compaction and settling. Settling on 24" of fill might be 2-4"; settling on 60" of fill; 5-10", maybe more. We aren't getting to 95/98% density with the tractor and pick ups.

 

[ruffdog]

I would think that is too low though. If the bottom of that dip is 7' lower than level with the rest of the driveway, and I already have material to either side, I would think I'd need to be at least a couple feet higher wouldn't I to keep the culvert fro being buried? Or maybe you are thinking I need to remove material on both sides to create a path for the water?

I would not keep the dip in there, at least not much of it. Hiring someone that knows what they are doing with a 6-way dozer would really jump start your project.

 

[dodge man]

What did the low spot look like before you started? I assume water drained through it. When you’re all done I assume water will still drain to it. Put the culvert in too high you built a dam and the water will back up until it gets high enough to run through the culvert. Put it in too low and water will force its way through it but will silt in over time.

 

[Too many Kubotas]

Part of my worry is cost, but also compaction and settling. Settling on 24" of fill might be 2-4"; settling on 60" of fill; 5-10", maybe more. We aren't getting to 95/98% density with the tractor and pick ups.

I really lucked out with my driveway widening, getting decent rain almost every afternoon, so compaction was relatively easy on a layer at a time.

Of course, this fill was no more than three feet thick, and I was pleasantly surprised when "testing" it with the M936 once it had dried out a bit. With 20,000 lbs. on three tires it only left normal tire tracks in the uncompacted road base, no ruts. How it'll work in the spring remains to be seen.

When making the pad for the barn I obviously had only one shot at it. Oddly enough I managed to be within two inches of level over 80+ feet (using no instruments) over slightly sloped ground and Morton claimed that it was the highest compaction they'd ever seen. Used a water truck and rented compactor for that one.

 

[future_vision]

What did the low spot look like before you started? I assume water drained through it. When you’re all done I assume water will still drain to it. Put the culvert in too high you built a dam and the water will back up until it gets high enough to run through the culvert. Put it in too low and water will force its way through it but will silt in over time.

The ground does slope from the high end of the driveway to the low end naturally and all the way to the back of the property. That is still the case unless we back fill some of that area which we might. Even backfilled there should still be a slope.

One of my thoughts, that wouldn't involve a culvert is to build up the high side until it is level with the rest of that side of the driveway. Then the entire driveway is level. Then handle water management either by pitching the entire driveway so the water sheets off to the low side. I was also thinking that if I went with a crown I could bury perforated pipe, wrapped in fabric, to both sides and move water that way. I've not seen it done that way before but it was a thought similar to what you would do along the foundation of a home.