What is permeable and if driveways need to be permeable, the question is why. Also if you need to make your driveways permeable, how do you accomplish this? Read on to get the answers to these questions.
What Does Permeable Mean?
This means that the material has openings or pores that allow liquids to pass through it.
With a permeable driveway, the paving used will allow water to flow through it instead of just racing toward the nearest sewer and instead, soak into the ground.
What Does Permeable Paving Material Do?
- Save you money on having to put in a new driveway
- They can cut the amount of rainwater that falls off the roof onto the driveway or ground.
Do Driveways Have to be Permeable?
No, driveways do not have to permeable but it is best that they are for environmental reasons and to give rainwater a place to soak into.
Rainwater has to go somewhere or it can overwhelm the drainage systems, causing pollution and flooding.
To help with this problem, permeable driveways are necessary.
The rainwater will pass through these types of driveways and soak into the ground instead of running directly into the drainage system.
If too much water gets into the storm drains it can overwhelm the lakes or streams.
Permeable Materials Used for Driveways
Loose gravel and stones:
This is the most common type of paving material that has been supporting traffic for centuries.
They are very popular because the driveways are easy to create, are very effective as this type of driveway, and can be attractive.
To make this type of permeable driveway you have to lay the gravel or stone over weed mesh and a sub-base.
It is also easy to maintain because the weed mesh will stop any unwanted plants from growing through.
The drawback to this type of driveway is that is difficult to wheel things across it and it is not good for steep driveways.
Plastic grid systems:
These are usually formed using recycled plastic blocks or grids that form a hard-driving surface that will allow water to flow through it freely.
They will last a long time, are maintenance-free, and easy to install. These permeable plastic grids are industrial strength so they will last for a long time.
They can be filled with gravel, soil, or sand but before this is done, they need to interlock and placed on a sub-base of gravel that is two to four inches deep.
It acts like a detention area that will hold the water temporarily to avoid flooding.
As the water soaks back into the ground, the pollutants are naturally filtered out.
These can be little more than a concrete version of the one above.
You would replace the plastic with concrete open cell blocks. Some of the more traditional types include solid concrete pavers, pavers in brick, and cobblestones.
The way to create permeable driveways using these materials is to use sand to fill the gaps between the pavers.
Open-cell concrete block pavers wok much like the plastic grid and let the water through but can handle heavier loads than the plastic grid system.
You can fill these with some type of grass or topsoil and it will hard to distinguish the blocks.
Permeable asphalt and concrete:
This may sound weird because you would not normally think of these as permeable but some new types of asphalt and concrete actually lets water to soak through.
It was developed to allow driving surfaces and payment-style parking where environmental regulations would not permit parking otherwise. On average, paving a two-car driveway approximately 640 feet with permeable asphalt averages $7,360.
In our environmentally sensitive times, these seem to be gaining new appreciation.
In the early days of driveways, it was a common thing to just run thin paving strips that were wide enough to handle the tires of the car leaving the rest of the ground grass-covered.
The paving strips were usually made from gravel. As time moved forward, driveways started to become asphalt or solid concrete driveways.
Although these types of driveways had their advantages they took more material to build them, added to the rainwater runoff problems, and cost more to install.
Today these types of paving strips are showing up in many new energy-efficient homes.
As long as you keep the grass around the paving strips well cared for and trimmed, this type of driveway will complement any type of house.
Also, the rest of the driveway will remain permeable and porous. These are also referred to as wheel tracks.
Maintaining a Permeable Driveway
The maintenance your permeable driveway will actually need depends on the type of driveway it is.
The most important thing to remember is a permeable driveway works by letting water pass through it and soak into the ground below.
You need to have pores and gaps for the rain to travel through so make sure that these do not become blocked.
- Clear any mud or leaves that collect on the driveway as these can break down and pass through the surface of your permeable driveway and block the pores or gaps.
- When dust or dirt collects on the surface, you can either brush it away or use a power washer on the driveway.
- Remove any weeds that show but do it by hand and not by using a weed killer as the weed can die, rot down, and block the pores or gaps.
- On the surface of the driveway do not put any materials like oils, cement, or sand as these could reduce the porosity.
- Make sure that if you have a garden of any type that the dirt and soil are not washed into the driveway.
- When you use permeable pavers for your driveway you are saving money and being environmentally responsible.
- With the growth of towns and cities, driveways are taking up more and more ground so there is less ground for the rainwater to soak into.
- Depending on the permeable material used to build your driveway, a homeowner would pay $10 to $20 per square foot.