Whether you purchased an undeveloped acre or two of land in a suburban community or you are homesteading away from town one of the first things that you will want to do is survey your land and then install a driveway for access and construction.
If you were building a development you would be required to have soil engineers come out and inspect your land. At that point you can make decisions on how you will have to place your homes, streets and utilities. Because you are only building for yourself you will either have to learn the skills needed or hire someone that can do the work for you. Because your driveway and then your building pad is not as highly inspected as a large development of homes you may think you can skip steps but if you do you are likely to run into problems that continue until you correct them.
Understanding Soil Quality
Soil quality will vary depending on where you are located but for the most part you can expect that undeveloped property will have a layer of topsoil that is made up of organic material and then under that a layer of lower grade clay and light gravel. A layer of better quality compacted gravel will come next which is good for driveways. Eventually if you dig deep enough or depending on your location such as in a mountainous area you will hit bedrock which is a material that is made up of stone and compacted gravel that can be extremely difficult to dig.
Depending on how your property is set and the elevations you may have to deal with all of these material types but for the most part you will normally first need to clear any trees and brush and then remove your topsoil down to good draining gravel.
Removing Topsoil
Topsoil is a very important part of your property. Although it is not desired for building pads and driveways because it can not be compacted to a sturdy material you will want to save all of the topsoil that you remove so that you can use it in other places where you need to grade your property. For this reason even if you are in a wooded area you will have to open enough area to store these materials. Not doing this will mean a large expense later when you are finishing off your property.
You want to remove the topsoil down to a layer of gravel that can be compacted. If you find that you have a clay mix then you can store that material separately from the topsoil.
This means you may need to excavate a number of feet along the entire path of your driveway and your building pad.
Removing Topsoil, Roots and Organic materials is really not an option. You can not come in and dump truckloads of sand and gravel and expect to overcome the organics in topsoil and if you do you will find that your road fails very quickly, your foundations will not be stable and you will spend large amounts of money to fix this problem and lose any gravel that you already dumped.
Sandy Clay Vs Gravely Mix
After the topsoil is removed you will normally have a clay base. Depending on its qualities it might be good enough to support both your driveway and your home’s foundation however the best way to know this is to have a soil compaction test run.
This is where contracting with an engineer for a test might be worth the cost. A soil compaction test can cost anywhere from $100 for a single location test to $1000 or maybe more. Although it is not as important for your driveway it is very important for undeveloped land if you are building a home with a basement or if you are building any type of custom home.
Civil Contractors that install driveways and foundations can normally give you a good guess when you have hit good material but the difference between a guess and knowing is running tests on the material.
If you have ever worked with clay in an art class you know that when it is very wet you can’t do anything with it and when it is too hard it will crack and crumble if you try to use it. A soil compaction test takes the moisture levels of the clay in the mix into account and tells you if you are going to have problems.
Problems can range from someone trying to build over a spring or an area that is very wet in some seasons or as dramatically different as very dry locations like West Texas, Arizona where when there is an extreme drought the clay can actually crush the walls of your basement.
It is an important step and if your investment is substantial then you really need to consider it.
If problems are found you might need to only dig a few feet deeper or you might need to amend your soil.
Before You Lay Your Gravel
Once you have a good idea about the quality of the soil and you have graded your driveway for easy slope you will have a choice of installing a Geo Textile material which is like a very thick and heavy tarp that will hopefully keep your gravel from being forced down into your clay and being absorbed over time.
The pros of Geo Textile is that you can expect much less maintenance on your driveway if it is going to remain a gravel driveway. It also might be suggested by your engineer after your compaction test. The choice is eventually yours but you should understand it can extend the life of your investment and prevent the yearly or biyearly dumps of gravel to regrade your driveway.
You might also consider a treatment called Chip and Run or Chip Sealing. This is where a liquid asphalt treatment is applied to the top of your gravel. It won’t give you that full asphalt driveway but it will seal your driveway to the point that you can expect less rutting and runoff water won’t normally wash out your gravel. It is an option to consider that isn’t as expensive as a full asphalt driveway.
Recycled Asphalt which is a gravely mixture is also an option for the top coating. This material will require compacting and base prep.
When you have your gravel installed you will want to start with a larger 2inch stone for drainage and then cover that with a 3/4 inch minus which is 3/4inch and smaller. Larger stone drains well and smaller stone compacts better although you can’t fully compact stone like you can a mix of clay, sand and gravel it will sit better.
Asphalt, Concrete, Cobble Stone Options
Depending on your property you may or may not want to go with asphalt or some other material over your gravel base. In a rural area the cost can be prohibitive but you may still want to install a large 20×20 pad of asphalt at your home for parking.
Concrete driveways are best suited for Southern States where there is little chance of salt use. Decorative boarders of cobble stone are a nice addition but also this is an expensive material.
If your home is in a HOA location you may not have the options to pick and choose the materials for your driveway. Remember to think about that if you are going to be the first home on the street to install a 100 foot long cobble stone driveway only to have to tare it out because of compliance.
Final Note
This How To has been an overview of what you need to know when installing a driveway on your undeveloped lot. As described the first thing that you need to do is remove all topsoil and organic material. You do not want to leave tree stumps and roots under your driveway or they will rot and repair will be required.
Getting a soil compaction test is a necessity for your home’s foundation and they can perform a test on your driveway area to assure you proper compaction is achievable with standard materials.
If you live in a rocky mountainous area or in a valley wetland area or in an area that has extreme weather conditions you will need to talk with an engineer about your property and make sure you understand all of your options.
Not every home needs a lot of work to install a good stable driveway or small road but for the price of a couple hundred dollars and at the time your engineer is inspecting your building site take the time to ask questions and possibly run some tests.
Personally I think Asphalt over a gravel base is the best product for residential homes especially in suburban communities. And when it comes to rural homesteads a large pad of asphalt in front of your garage gives you a place where you can work on cars and equipment easily.