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Phil, Mechanical Engineer
Category: Home Improvement
Satisfied Customers: 8702
Experience:  Retired contractor, 51 years experience
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Driveway Repair Question: Heres my situation - Im working

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Driveway Repair Question: Here's my situation - I'm working with an experienced neighbor (who has the required equipment) to rip out the lower 100' feet of our asphalt drive and also widen the next 350' of the drive. He's already excavated the sides of the upper part down to clay or the needed depth. Now he's going to start tearing out the entire lower 100', which will be paved by an asphalt company later in the year after we put down some recycled concrete (just adding 411 to this section because it already has a base; we will use 304 recycled concrete and a 411 topping for the areas that we widen in lower 100').

As for the upper 350' that is being widened, about half of it (closet to house) is asphalt above a concrete base. This section just needs to be crack filled and widened. The other part of upper 350' was not supported by concrete, and it's breaking on the edges. So we're going to reuse those broken pieces as base for the widened part and then have a decision to make. To we have the asphalt company make a clean cut on the broken edges and then add asphalt to the width of the original drive or all the way over to the widened drive. There's a city regulation that you need to be 10 feet from the side lot, which only comes into play near the house. And I think this only applies to concrete and paved asphalt, not asphalt grindings or other non-permanent material.

Anyway, I'm trying to figure out whether I should use 304/411 recycled concrete or asphalt grindings (reused broken up chunks from existing drive and then #4 asphalt and then 411 asphalt as topping) for the upper 350' of the widened drive. We live in a cold climate that gets a lot of snow in the winter, so it will be plowed.

Also, I'm going to use Terratex GEOW200 soil stabalizing material (plastic woven silt) under widened part of drive (upper 350'). Any suggestions on proper installation would be appreciated. I assume it just needs to be laid down with at least 1 foot overlap on cut sections. But I wasn't sure if there was more to it such as having it 1 foot over sides and then cover with clay and topsoil when done. Please advise. Thanks!
Welcome to Just Answer!

The reason you have not gotten an answer to your question so far is that you and your neighbor have already demonstrated competence well beyond most people in the road construction and paving business.... and that to go further with design strategy, soils and drainage analysis is required, and that is costly... probably not warranted on this project.

Beyond that the project would have to be seen to offer any better advice than what you are already planning on doing.

A civil engineer specializing in road construction would be the only person I might recommend, and again he would have to see the job and get a soils analysis in order to offer better advice than what you already have. That expense is also most likely not warranted in this case.

I am offering this comment as an information request, because it does not answer your question.

Stay in touch if you wish, there are no time limits. Thank you for being a loyal JA customer!

Customer: replied 4 years ago.

Thanks, Phil! My neighbor came over and used his equipment to rip up about 110' feet of the lower drive. He broke up the pieces as best that he could and we are using them as base. I was out there too, helping as much as possible with the smaller stuff. Things went well. We're done for today because it's 90 degrees, and I had a dentist appointment. My dentist told me cement isn't that much more that resurfaced asphalt. Do you agree with that statement? Also, would we still be able to use the larger chunks of asphalt broken up as a foundation for the cement (assuming it's not much more expensive than asphalt)?

Hello again, low quality asphalt will slide down hill a bit in really hot weather and deforms more easily over time than concrete. High quality asphalt as used on government projects will work well on steep grades, low quality asphalt will tend to sag down hill a bit over 10 or 20 years. Asphalt needs regular maintenance.

Concrete needs only minimal maintenance.

the broken pieces of high quality asphalt should be OK as a base....soft asphalt pieces would be ok mixed with 1 inch crushed rock as a base... 30% of the softer type asphalt mixed with crushed rock.

All of that is quite a science depending on the conditions, vehicles used. On new projects three sizes of crushed rock are recommended, starting with 3 inch on the bottom, then a layer of 2 inch. then some sand, then 2 inch and finally 1 inch crushed rock... minimum of 4" concrete over that. or 2 to 3 inches of asphalt. The base can be anywhere from 6 to 12 or more inches deep depending on the sub soil and load.

The cost of concrete VS cement varies with the thickness and quality of the job in either case. Concrete is generally a lot higher in first cost, and lower in overall costs over time if the drive way is level and easy to pour concrete on.... on steeper driveways asphalt is a home owners best option.


Let me know what you think, we can go from there if you rate my assistance *positively. There is no time limit.

Customer: replied 4 years ago.

Thanks for your help! I'm going to contact our local building inspector to find out if my city has any requirements. It looks like we're going to rip up the entire drive, even the shallow layer of asphalt (2") that's over the cement foundation. All of the ripped up asphalt will be used as base material somewhere on the existing or expanded drive. I will take your base recommendations above into consideration. It's going to be a major project but it'll save me about 50% versus paying a company to do the entire thing. I got a quote for 4" of cement at $5 per square foot. He said this would be the minimum cost, assuming all the other work is done. It's someone I know and trust. The 3" compacted asphalt quote is $1.25 per square foot plus about $1,000 per day in labor. This job would be at least 1 day, possibly 1.5 days. Roughly, the comparable asphalt cost (with labor) would be about $1.75 per square foot. But we'd have the ongoing maintenance with asphalt that is not the case with cement. It's going to come down to money. But I realize it's pay now or pay later. Any advice?

Hello again

In this economy I would go with the 3 inches of asphalt, especially if I did not plan on living in the house for longer than 25 or 30 years. The asphalt can be resurfaced with chip coat if you want it to look good when you sell.

The quality of the asphalt used is a key factor... it will pay to study that up a bit and discuss the options with several commercial paving contractors... the gold standard is whatever the city and state use in your area. (that varies with climate)

If you choose to rate my advice *positively I will appreciate it and be able to hold the question open for any follow up needed.



Phil and other Home Improvement Specialists are ready to help you
Customer: replied 4 years ago.

Phil, I read the article in the link you provided. Good stuff. But I need some clarification on your response about the base. You said previously:


"All of that is quite a science depending on the conditions, vehicles used. On new projects three sizes of crushed rock are recommended, starting with 3 inch on the bottom, then a layer of 2 inch. then some sand, then 2 inch and finally 1 inch crushed rock... minimum of 4" concrete over that. or 2 to 3 inches of asphalt. The base can be anywhere from 6 to 12 or more inches deep depending on the sub soil and load."

You said 3 sizes of crushed rock are recommended. But I wasn't sure if you were referring to the depth of the layer or size of rock. Maybe it's 3 sizes (1",2" and 3") but multiple layers of different depths. Any clarification you can provide on this or resources/reference material would be appreciated. Also, remember that we already have an ample supply of broken up asphalt that we're trying to use as bottom base. Thanks!




Hello again, the issue with the broken up asphalt used as a base, is that it will distort over time under a load, to some degree or the other... as compared to crushed rock will tend to distort as well, but to much lesser extent.

I am referring to the size of rock in 3 layers... depending on the underlying earth, 3" diameter on the bottom, so it will not press into the soft soil as easily as smaller diameter crushed rock, then 2" crushed rock then 1"... the formula varies according to the soil conditions.

Using the broken up asphalt I would spread the larger pieces on the bottom then spread the rest over the top... some crushed rock mixed in would be a good idea...then run a roller over it.



That vendor suggests 2" crushed rock as the bottom layer of the base...thats fine in most areas.. 3" is better for wetter areas... the deeper the base the larger rock you can use at the bottom.

The more 'fines' you mix into the base material the stronger the base will must all be 'road grade CRUSHED rock'... when you mix such it with old asphalt you compromise the base a bit, but not to any great degree if compacted properly and the base is deep enough relative to the underlying soil conditions.

There are many factors, for instance clay soils expand when wet, and then shrink drastically when dry, that can raise havoc with any sort of road or driveway construction.

CLICK HERE read the section on clay soils and other soil conditions. You may have to adjust the base material to suit changing soil conditions.

Customer: replied 4 years ago.

Thanks again!

You are welcome.

Customer: replied 3 years ago.

Hi, Phil! It's me again. Well, fall is here and I need to deal with my driveway situation before the winter comes. My Grandpa died last month, and I've been busy at work and other home improvement projects, so my driveway was put on hold. Now I need to get it done. I read through the links you previously sent. Thanks again. Below is an update on my situation.


For the 100' of our lower drive that my neighbor and I removed the top layer of broken up asphalt with his backhoe, I plan to replace a drain pipe from one side of the drive to the other (any tips on this would be appreciated) and then to put about 2-3" of #57 limestone over it. This should get us through the winter and look nice.


For the shoulder or berm of one side of our drive closer to the house, it's been excavated about 12" deep and to various widths. I originally had my neighbor dump all the broken up asphalt from the lower drive into the trenches. Now I'm thinking that I should do more of what you were talking about in previous posts (crushed stone instead of asphalt as base). What do you think of this post:



Also, if you think it's a waste of time to remove the existing asphalt that I still need to break up into smaller pieces, let me know. But I may have to do this anyway to get a level sub-base. That is, unless I just break up the asphalt and then put other layers of asphalt grindings on top of it and pack the layers down properly. But right now the ground isn't level. It's deeper farther away from side of drive. So I did what's in the link, I'd want to level the ground and put the layers in accordingly. Anyway, let me know your thoughts. Thanks!

Hello again,

These sorts of issues are a trade off. Personally I would leave the broken up asphalt in place then fill in above it with a mix of crushed rock in various sizes as the article describes, you can mix some of the ground up asphalt with the rock and that would make a very good base for 4 inches of re-bar reinforced concrete. 4 inches minimum in the middle, it you intend to run heavy trucks over it 5 inches or more would be a good idea, use #4 rebar (half inch) on a 12" grid pattern for a bullet proof job... or for a generally good job you can put the rebar in on an 18 to 24 inch grid pattern... the more you compact the sub base the better.

regarding the drain you can get by with 4" schedule 40 PVC fit with a way to clean it out, a 'clean out' wye most usually if it is under the 4" or thicker slab. (with no slab, just the stone/gravel combination, you should use schedule 80 PVC, much stronger, also more expensive. Slope should be at least 1/4 inch per foot with no bellies or humps in it...and 2 inches of sand under and over it.

I will put up the ratings box again in case you feel like rating my extended assistance. Its your option.


Phil and other Home Improvement Specialists are ready to help you
Hello again, thanks for the second rating!

Be sure to seal the driveway after the concrete has cured completely... follow the directions on the can of sealer you use... re-apply every few years. That keeps micro cracks in the driveway from leaking water onto the rebar. and allows you to clean grease and stains off of the slab more easily later on.

Customer: replied 3 years ago.

Hi, Phil! Well, this holiday weekend (Columbus Day) is when I'm having the stones delivered and spread. Our weather is supposed to be dry and nice. So it's a good time to do this outdoor project.


One clarification I need from you is whether recycled concrete is acceptable as a base. Above you had mentioned only using 'road grade CRUSHED rock'. As of right now (there's still time to change, for the part of our drive that we're widening, here's what I plan to do:


* I'm having #4 recycled concrete delivered on Saturday morning. It will go over the existing chunks of broken up asphalt to create a base of 6-8".


* After leveling and compacting the #4 down, I'm going to have #304 recycled concrete delivered on Monday and plan to have it 3-4" deep. Again, it will be leveled and compacted.


* Finally, I was going to have #57 limestone top it off at about 2" deep.


If we end up paving this section down the road, I'd put down 411 gravel with fines and pack it down prior to having asphalt or pavers laid down.


For the bottom of the drive, I still plan to have about 2 inches of #57 limestone added to the existing base, which is only about 6" of compacted gravel. Down the road if we end up paving this section, I'm going to need to excavate this lower 100 feet and put in a proper base. The previous asphalt in this section was broken up badly. That's why we removed it and used it as a base for the upper part of drive that we plan to widen. After digging out the old corroded drainage pipe last night (with my neighbors backhoe), I realized how insufficient the base is. But I'd deal with this down the road.


Anyway, I really appreciate your help. I've been reading various things and talking to various so-called "experts" and others, but a lot of their advice conflicts so it get confusing to me sometimes. Any additional help you can provide regarding the wisdom of using recycled concrete (potential runoff issues? stability?) versus asphalt grindings or crushed stone would be helpful. Also, if you have any other tips, I'd be thankful. Thanks for your patience with me. But I guess that's what JustAnswer is for. I'll rate you again you address these other questions. Thanks!


Hello again,

The crushed concrete is good. That driveway should last very well. you are installing a better base than 9 out of 10 driveways ever get.

Opinions vary for many reasons, one reason is that the soil under the driveway and the drainage varies, and the load varies. Some contractors do a better job of compacting than others. All that provides different results.

You would tend to have trouble for instance if you had a belly (low area in the drive way) that was not drained and tended to collect water when it rained, and if the soil in the area was clay and expanded greatly when it got wet, then shrunk dramatically when it dried out... that movement would weaken the base and it would not last as long as other sections....

Some driveways will get a heavy garbage truck running over them others will not... combined with poor drainage and very soft soil that will shorten the life of the driveway.

You seem to be well aware of these drainage issues so will not have those problems, and you are installing a sufficient base up to heavily traveled county road standards, your drive will see 98% less traffic and virtually no heavy truck traffic. You should end up with a very high quality and long lasting drive way.

Thank you for your consideration on a second rating. Stay in touch as necessary.


Customer: replied 3 years ago.

Thanks, Phil! One thing I forgot to ask was should I install some kind of vertical separator to provide support for the stone and keep any roots, etc., from coming under the driveway? We've cleared out a bunch of roots already with the backhoe, but I'm sure they'll come back. Down the road I may add some type of edging on the top to help keep in any gravel. And I do plan to pack the topsoil along the edges. Any thoughts on this last component?

Hello again,

You were originally discussing base construction for a *paved driveway.. that keeps the clay under the driveway dry, and eliminates expansion and contraction issues with driveways over clay.

Then just recently you have suggested that you might not pave and go to just 2 inches of crushed stone at the top... that allows water to the base soil, and weeds can then grow up through it. you need a weed barrier below the base rock in that case... its two different systems. the two don't mix.

For roots, cut off any that are growing under the drive currently and fit a fiber glass/ abs root stop material as deeply as possible, depending on the species of bushes or trees, depths are specified.

it will be clay soil around the rock base that holds the rock in place, not the root stop material.

Customer: replied 3 years ago.

Sorry for the confusion, Phil! We will eventually (5-10 years) either pave with apshalt or brick pavers over this widened drive and also the lower section. But for now we're puttling down the base (asphalt chunks and #4 and #304 recycled concrete contained by clay on sides) and then topping off with #57 limestone (probably contained with some type of edging. When we do pave with asphalt or pavers, we'll add for 411 (and sand for pavers) on top of existing #57. I hope it all works out. Wish me luck!


One last clarification on the weed barrier...are you saying to add that on top of the 304 recycled concrete but below the #57 or am I misunderstanding your suggestion? When you respond, I'll rate you again. Thanks!

Hello again, the heavy duty driveway membrane is best placed under the base onto the well compacted clay.

The higher elevation sheet of membrane should *over lap the lower sheet, so water is shed from the slope and not allowed to run underneath the adjacent sheet. That will take some thought. It is a permeable membrane but still sheds a lot of water.

You would not want to fit the membrane between the top layer of gravel and the lower layers, that would prevent the top layer from binding to the lower layer.

If you already have the large diameter base layer in place you might be ok putting the other 10 inches of gravel over the top of it,, but that is not standard practice...since the bottom layer is so course however it will still grip the rock over the top of it. There are no tests on that however, it might tear the fabric in spots and allow some weeds through in those areas,

I will send this now before we loose it, we can discuss it more later,