What is permeable paving? And what are the Best Permeable Paving Options for your driveway or pathway?

What is Permeable Paving? 

Permeable paving is a paving solution where the surface water passes through the paving, rather than washing off the paving surface.  

This means that the rainwater drains into the soil underneath the paving, making sure the water table stays level and reducing the amount of water reaching the public water system, streams and rivers. 

Until recent years the word permeable wasn’t even associated with driveways – that all changed after severe flooding in several regions of the UK. 

This prompted the government to act and increasingly this filtered down to local councils (with enforcement in mind) to assess all new driveway installations. 

The results were sustainable urban drainage solutions (SUDs) policies to reduce the amount of surface water and with that to reduce the chance of flooding.  

Now all new driveway installations either need to be permeable or have a drainage system in place which allows the surface water to drain into the ground on the property rather than to reach public drainage systems on the road.  

As a result, this takes pressure off the public water system. 

Permeable Gravel Driveway

Source: @improveoutdoors

Gravel driveways are the traditional permeable driveway surface and with the installation of gravel grids underneath,  you can prevent gravel loss as well as ruts on your drive.

Permeable pavers – pros and cons 

As with everything there are pros and cons to permeable pavers and permeable driveway surfaces in general. We list them for you here 

Pros 

Permeable driveway and pathway surfaces are more environmentally friendly, as the surface water from your driveway soaks into the soil underneath the surface.  

This is good because: 

1. It increases local ground water sources 

1. Surface pollution stays local rather than collectively reaching streams and rivers 

1. Reduces the risk of flooding 

1. The surface water from your driveway doesn’t reach the sewage systems which doesn’t have the ability to deal with excess surface water  

Cons 

The cons of permeable pavers and permeable surface options in general can be the cost.  

If you choose permeable pavers, there will be a premium price tag attached. Resin is also a more expensive driveway surface overall,  

However, gravel, drivable grass and wheel tracks are 3 driveway surface options which will cost significantly less.  

While we believe the pros far outweigh the cons, it’s of course up to you which driveway surface you think is most suitable for your home. Should you choose a non-permeable surface however, a good drainage system is a must. 

Permeable Resin Driveway

Source: @farellyconstruction

Resin bound driveways are permeable as long as the subbase is also permeable. 

Permeable paving options 

The following surface options are permeable, are beneficial for the environment and therefore more desirable. 

Gravel 

There are many good reasons to have a gravel driveway. It’s cost effective, it’s aesthetically pleasing, there are many colour options available and it’s a good security option.  

There are some reasons why gravel is not popular with everyone. Traditionally, gravel driveways need levelling as driving on them moves gravel constantly, not only to different places on the driveway but also into the tyre tracks and even the road. It’s also not a very good option for sloped driveways due to loss of gravel.  

However, gravel driveway grids (gravel retention mats) are a great technology which ensures the gravel stays just where it needs to be. This reduces the movement of gravel and minimalizes maintenance. It’s even suitable for sloped driveways.  

While there is an extra upfront cost for the grids, in the long run it will be more cost effective as you don’t needs as much gravel on your driveway and you hardly lose any gravel at all.  

Resin Bound Driveway 

There are two resin surface options. 

Resin bonded and resin bound, though often they are just referred to as a resin driveway, so it’s best to confirm clearly with your installer which resin option you want for your driveway.  

Resin bound is a non-permeable surface product where a layer of gravel is thrown onto a surface painted with resin. This resin surface option is not very durable, and many stones will get lose over time as they are only glued on one side. This means you can end up with a driveway full of ‘bold spots’. 

Resin bound on the other hand is a permeable paving solution where gravel is mixed with resin and is then spread evenly onto the subbase of the driveway or pathway. As long as the subbase is permeable, your driveway is permeable. 

Most driveways will be resin bound as it’s more durable and a better option from an environmental standpoint.  

This driveway surfacing product looks fantastic and is most suitable for very lightly trafficked driveways. 

A wide range of colour combinations are available and both installation and maintenance are easy. 

Use a firm with a portfolio of work you can view. 

Use our Directory and choose a businesses with an established track record. 

Wheel tracks 

This is a very simple and cost effective way to be able to park your car on your driveway. All you need are two lines of slabs or blocks where you’ll drive your car. The rest of the driveway can be grass or gravel.  

This type of driveway is slowly becoming more popular.  

Drivable grass / reinforced grass driveways 

Increasingly, permeable paving options such as grass grid systems are becoming more popular as the ultimate eco driveway option, bringing more greenery to urban spaces.  

If using for a driveway, make sure you use heavy duty grids which will have a high permissible load of at least 500 tons (when filled with gravel).  

This is a truly ‘green’ driveway surface option. 

Chessboard Permeable Paving

Source: @improveoutdoors

Tiles Surrounded by Grass

Source: @improveoutdoors

While this environmentally friendly, permeable driveway looks similar to the checkered driveway in the image above, on this driveway, the pavers are surrounded by grass, creating a completely different design .

Excess rainwater problems 

Another problem adding to the surface water is rainwater from the roofs. After all, all areas which are non-permeable produce excess water. While we have gutters and drainpipe systems, not all drainpipes end in drainage systems once the water reaches ground level.  

Especially stormwater can cause big flooding problems when sufficient drainage is not in place.  

Therefore, it’s important to have a drainage system in place which can deal with large amounts of rainwater, though of course it would be even better to have permeable paving installed.  

Is block paving permeable paving?  

Many people assume block paving allows surface water to drain through. 

It doesn’t. 

Block paving is made from concrete (or sometimes clay) and in terms of driveways the only difference from a water drainage point of view is some (a tiny amount) drains through the gaps of block paving compared to zero drainage through a concrete slab (like decorative concrete). 

But a solution is at hand! 

Permeable block paving has been developed by the main manufacturers and  Marshalls Tegula Priora is a great example of this. 

Permeable blocks are shaped so there is more space between the blocks which allows better surface water drainage. Whilst these blocks have been designed to be permeable, they must be installed on a suitable sub base otherwise they won’t work.  

And……your driveway must be suitable for a permeable block paving installation in the first place. 

Check here for permeability suitability! 

Permeable Block Paving

Source: Marshalls.co.uk

These permeable blocks are from the Marshalls Tergula Priora range. There are several colour options available.  These blocks is a great choice for a permeable driveway surface.

Long grass blocks

Source: @smartstonebloemfontein

These blocks are designed to combine the benefits of paving and vegetation in a stylish way.

The long blocks make the driveway look larger than it is. 

What is a suitable sub base for permeable block paving? 

With permeable block paving the installation of a suitable sub base is critical. Come to think of it the installation of a suitable sub base is critical for any driveway, but you knew that already we hope. 

How’s the sub base different? 

A typical driveway using type 1 MOT (roadstone) as a sub base. This provides stability and compacts beautifully. However, it does not allow much water through. This is due to the finer particles compacting and stopping the flow of water. 

So, in terms of a permeable sub base installation for block paving: 

• Use crushed stone (20mm (about 0.79 in)) that has well defined edges and not rounded 
• Installation to a depth of 200mm (about 7.87 in) 
• Compaction is essential 
• Then use 6mm (about 0.24 in) clean crushed stone to depth of 50mm (about 1.97 in) 
• Compact again 

What is the difference between pavers and permeable pavers 

Normal paving slabs are either made from clay but more often from concrete. These aren’t permeable. The sand between the pavers is permeable in theory, however, the space between the pavers is very small. On top of that, a layer of sealant is often applied to the pavers, making the sand more or less non-permeable.  

To have truly permeable pavers you need to invest in pavers which have either an opening in the middle or which have special edging which allows more water to drain through in between the pavers.  

What is the purpose of permeable pavers? 

The purpose of permeable pavers is to reduce the pressure on the public drainage system, to reduce local flooding, to reduce surface pollution reaching the public waterways and to top up the groundwater resources locally. 

Open Permeable Blocks

Source: @improveoutdoors

In the next two examples, open bricks are used. While the blocks fit nicely together, the inside is open, allowing rainwater the drain and grass to grow. 

Stone Pathway

Source: @improveoutdoors

This permeable block is different in shape to the block in the image above, but the effect is the same. 

How do driveways add to the flooding problem? 

When you think about it, with our insatiable need for more and more cars, a consequence has been the mass ‘concreting’ over many front gardens. 

Hardly environmentally friendly! 

These gardens had previously soaked surface water away from properties and public water systems. 

In terms of driveway installations non -permeable paving usually needs separate installation of drainage. 

Non permeable paving includes concrete and most blocks and most tarmacadam. 

As you can imagine this has driven up the demand for potentially permeable driveway surfacing such as resin bound and even gravel driveways. 

How does permeable paving work? 

Permeable paving needs to allow water to drain through without softening and weakening the paving surface.  

Installation of Drivable Grass

Source: @piperwhitneyconstruction

Are permeable pavers better?

Permeable pavers are better for the environment for several reasons.

First of all, the water drains through the pavers making sure the rainwater drains into the ground water supply.

Secondly, surface water is polluted and when if lots of surface water drains into water systems, rivers and streams become more polluted.

Lastly, the public drainage systems on the roads have not been designed to deal with large amounts of surface water. The water will end up in sewage systems where the water needs to be treated. This costs more money but is also a problem because the sewage systems can’t process everything when there is lots of rainfall. There have been instances where raw sewage has been pumped into the natural environment. Not good!

Conclusion:

What is permeable paving? And what are the Best Permeable Paving Options for your driveway or pathway?

Permeable paving is the better driveway and pathway surface option as it is the more environmentally friendly option. It also reduces the risk of flooding, contains surface pollution and fills the groundwater resources.

Other ways to reduce rainwater reaching the public waterways are rain gardens, green roofs and simply having part of your driveway as a garden with grass, shrubs or flowers.

We believe permeable paving is future proof and worth the investment!