Pavers over asphalt

[Stonehenge]

Looks like I get to break this forum in! :D

We did a driveway project last year, laying pavers over asphalt. The asphalt was not pre-existing, it was prepped and installed to our specs for this specific project.

We're always looking for new ways to do things - has anyone else installed a paver project this way, and if so, what kinds of things did you learn when you did it?

BTW, we saved a ton of labor and made a nice profit installing this driveway this way.

This is what it looked like in the beginning:

[Stonehenge]

And this is what it looked like when completed:

[Bexter]

Stonehenge ... I would be interested in why you would do this? You say you saved a ton of labor ... please explain? Did you put a layer of sand ...oops screenings in your case ? lol

It looks great!

[Stonehenge]

Well, a supplier of ours was telling me about some information he read in a concrete/masonry trade mag, and was thinking about this idea - so he did some research on his own, and presented it to me.

As I'm sure you know, base prep is where we earn our money, so I was apprehensive about giving that part away. So I contacted a civil engineering prof from my alma mater and asked him about this idea, and the specs we were tossing around.

Turns out we could have a shallower depth of base, and still have a final product that was more stable than our current methods.

And the beauty was, for the pictured project, for example, our total material and labor cost for 1,100 sqft was about $3,500. That's all base prep, the cost of the pavers, the labor to lay them cut them, edge restraint, etc, etc, etc. It stands to reason we made a few bucks on that project.

And yes, that was one of the rare circumstances when I used sand over the asphalt. 3/4", down to about 1/2" after compaction. Helped to mitigate any slight grade changes in the asphalt.

So the net result was - a better project, that we could make more money, and still charge the customer less than our 'normal' rate. Seemed like a winner all around before we started, and turned out to be true.

[Lanelle]

I hope we can continue to follow this project. I will be interested to hear how it fared over the winter. Maybe you could share a picture of the far end of the project also. Looks nice!

[Paul]

We have done a few installs like this, only differance is we like to use 3/8" ground rods, Less sand is used (not that much is used) and we have better control on water holding in the sand. because these areas are typically small areas (under 300 sq ft) and conected to pavment we have to watch for trip hazards.

[Stonehenge]

Paul, one of the things we had recommended to us, that we did on that project, was to make some relief cuts in the asphalt prior to beginning work, to allow water to pass a bit more freely.

Is this something you do as well?

[Paul]

At times we do do this but others we might have problems with it. We have done bridge deck with pavers and they don't like holes in their structure :)

[Rex Mann]

Jeff,

Great looking job. As you know, I am always looking for that better methodology to improve our industry in paticular my little world. What and how did you handle edge restraints?

[Stonehenge]

Great to see you on board Rex!

Edge restraint for this project was handled using our normal aluminum edge restraint and spikes. Just trowel away the sand (pic below) and start adding restraint. However, sledgehammers were required to poke those spikes through the asphalt and stone. Much, much harder than we were used to. At one point I had all 4 of us putting in edge restraint.

For the future, we may pre-drill. Also, for places where the sides of the asphaltic pavement will fall away from the pavers, like for a culvert, we intend to use angle iron, cut and drilled and spiked, affixed to the base with spikes, but prior to the asphalt being laid. So when the asphalt is installed, the edge restraint will already be there. Took lots of thinking among several people in different parts of the industry locally to come up with that one.

The asphalt to ask for is called a 'binder course'. It uses a much larger stone - makes it stronger, but not as pretty. Still perfectly flat, just not a 'creamy' top like a concrete.

http://home.earthlink.net/~stonehengebpl/wittlin_trowel.jpg

[PSUscaper]

Hello,

How thick was the base course of asphalt?? And what kind of base material/thickness is under it?? I know things may change do to site conditions, but just looking for some generalizations.

This is a very interesting idea to me.....I remember you talking about it a while back.

I think it may be a interesting idea for new home constructions..........mainly pertaining to budgets.

I've noticed that, when people by a home and start landscaping, budgets often become a concern. After they get done with the lawn, the walks, the patios, etc. etc., the drive becomes one of the last issues.

My point is, when people get done building a house, they are slightly strapped for cash for a few years.

What I'm thinking is this. Because a paved drive is often required for a CO, and also, because people don't want a gravel drive, maybe a 'phased construction' principle could be negotiated.

If people want a paver drive, but want to wait a year or two, they could first do a 'base' course of asphalt, then when they have recovered from the initial hit of the new house, they can elect to have a paver drive installed.

I know it may not be pretty having a base course drive for those 2 years, but it may be a good way to finacially spread out the cost of a paver driveway.

steve

[Stonehenge]

Steve, you hit on exactly one of the reasons this is so great. After the asphalt is laid, they have a functional drive. Not gorgeous, but functional. Which means that you don't have an anxious customer waiting impatiently to be able to put their cars in the garage. Asphalt can be laid, and you can come back in a week, month, year to do the pavers (though I'd not want to wait a whole year :rolleyes: ).

As for base prep, I have the asphalt guys do the prep they would normally do for asphalt drives - around here, with the company we use, that's 6-7" of 3/4"-. But for our first go-round we probably went 10-12".

Asphalt depth - 2" of binder course.

1/2" or less of sand. We went for 1/2", we'll probably go for less in the future.

[guido]

I'm digging through some old posts and I found this one, and after reading all the comments I feel real stupid because I'm still sitting here scratching my head with about 6 of my co-workers doing the same. I have done sidewalks, patios, driveways, and parking lots over the last 5 or so years in Germany in both Asphalt and in pavers or sometimes a combination of both.

Here's the mystery for me..... I don't understand the cost savings between the 2 options.....

I see option 1....build your own base (6" - 8" or 10"-12" if you want to get really crazy for a residential driveway) and then lay your sand and pavers ontop of that

or

I see option 2...which seems it would be much more expensive to me...is to hire some other company to come in and build that identical base, and then throw a binder lift down on top of that, and then you still have to lay your sand and pavers on top.

It looks to me like option 2 would be more expensive because your paying someone else to build the base you need (with their profit added) plus your paying for x tons of asphalt on top of that.


There has to be something I'm missing in this equation somewhere, because I know that asphalt costs more than nothing costs, and now I have confused myself too!

So Jeff, please fill in the gaps for me so I could understand this method a little better. The only thing I can see is it might be more cost effective to outsource such a large base to someone with larger equipment, larger hauling operation, etc, but the asphalt part I don't get.

Thanks, and I hope no one takes this the wrong way....I'm just not getting the full picture I'm sure. I've been working in Europe for 5+ years and have got accustomed to their way of doing things and now that I'm returning to the US shortly I have to catch up on what I've missed over the past few years.

Thanks in advance for some clarification!

[Stonehenge]

How exactly the asphalt company handles their costs, I can't say. They are a larger outfit with their own quarries, and I believe the binder course to be less expensive than the finish course. I also think they have economies of scale with the prep tools they use, big rollers instead of compaction equipment.

Also, they don't do any screeding in their prep - box blade on a tractor to get things close, roll it, check with laser, spread asphalt, roll until they hit elevation. That's quite a bit faster then us setting pipe and screed, screed, screed.

Lastly, however they approach it, the end result is they give me a prepped surface I can drive on (with a skid steer) for less than I can do it myself (we always do 10-12" prep for driveways).

[GLAN]

I know some paver driveways that they poured a concrete base. A thin layer of sand. Pavers on top.......sweep in over the top.........done.


I am just thinking that maybe doing such a base is due to the freezing and thawing we experience?

Be surprised what just a little water getting in underneath the damage it will do when freezing........Right in front of my house the street pavement tends to swell in the winter as the snow thaws and then freezes at night.....this is due to some cracks in the black top

[guido]

I guess the more I think about it, and think about laying pavers on top of asphalt/sand, the way you can save some money is the time you save after the base is done. I guess you can save a lot of time on a project that size being able to bring the skid steer right up to the last bit of sand you screeded.

As far as freeze thaw action is considered.....asphalt and pavers work in freeze thaw if constructed correctly....

Concrete though is another story....thats a rigid pavement not designed to flext the same way pavers and asphalt do, so if you put pavers on top of a concrete base, it ends up that the pavers are just for looks because they're not performing their job as a flexible pavement if there is a rigid one under neath it.

[GLAN]

Now would the concrete base be any different than a brick walk that was set in concrete and mortar?

I understand that there would be no flexability.

In a driveway situation then there would be no risk of wheel ruts.


Me personaly....I am tossed in the air on this.......for reason that when my sister had purchased a new home in Foot Hill Ranch in So. Cal. I did pavers for her and several neighbors over 2 winters. I used no mortar or any concrete at all..........All other contractors there did...

After a couple ground shakings......All the ones I did settled out nicely........everyone else........had damage

[Stonehenge]

And we cut grooves through the asphalt to allow for drainage. We also use poly sand to try to prevent water from getting into the sand in the first place.

So far the results have been pretty outstanding.

[GLAN]

Poly sand?.......poly coated like fertilizer?


Haven't heard of that here.

[Paul]

Concrete though is another story....thats a rigid pavement not designed to flext the same way pavers and asphalt do, so if you put pavers on top of a concrete base, it ends up that the pavers are just for looks because they're not performing their job as a flexible pavement if there is a rigid one under neath it.

Not all the time, Pavers are used as a wear layer on bridges, as a covering on parking decks and a replaceable layer on sidewalks meeting ADA standards.

[Jake]

Polymeric Sand - resists erosion, reduces weed growth, resists insects. Applied in "dry" sand (have you ever gotten DRY sand from a pit?) form, sweep and tamp as usual. Lightly spray with water when done. Sets up hard in 24 hours. Cool stuff!

[guido]

This ploymeric sand I hear about, is it sold in bulk or bags??? Who makes it?