Permeable driveways in Milton Keynes: are they worth it?
By Terry O'Reilly, owner, 17 years on the tools. Updated . 5 min read.
Yes, for most Milton Keynes houses. A permeable driveway lets rain soak through the surface into the ground instead of running to the road, so it needs no planning permission whatever its size, it does not puddle, and it takes pressure off the drains. Resin bound and permeable block paving are the two proper options; on MK clay the base and a soakaway matter as much as the surface.
What is a permeable driveway?
A permeable driveway lets rain soak down through the surface into the ground, instead of running off to the road. It is one of the ideas behind SuDS (sustainable drainage systems): dealing with rain where it lands, so the drains in the street are not flooded in a storm. In England a permeable front drive needs no planning permission at any size.
| Surface | Permeable? | What to check |
|---|---|---|
| Resin bound | Yes, when laid on a permeable base | On an old solid concrete base the water cannot get away, so it has to drain to a lawn, border or soakaway |
| Block paving | Only permeable block systems | Standard block on a sand bed counts as a solid surface and needs to slope to a lawn or border |
| Tarmac | Standard tarmac, no. Porous asphalt, yes | Standard tarmac needs a slope to a lawn, border or a channel drain into a soakaway |
| Gravel | Yes | Loose stone walks onto the path and needs topping up |
What does permeable actually mean?
A permeable drive is one where rain goes through the surface and into the ground beneath, rather than running off the top to a gully or the road. The surface has gaps in it, the layers under it are open stone that holds water, and the ground or a soakaway takes it from there. A solid drive, tarmac or concrete or tightly jointed block on a solid bed, is the opposite: water runs off it and has to be collected somewhere.
There are three ways to get a permeable drive:
- Resin bound. Stone bound with clear resin and trowelled smooth. There are gaps between the stones and water drains straight through. Permeable by design, no loose stone, no weeds.
- Permeable block paving. Blocks made with wider joints or spacer nibs, laid on a base of clean, chunky stone with gaps in it, so water drops through the joints into the base. Looks like normal block from a few feet away.
- Gravel. Permeable and the lowest cost, but it walks into the house and onto the path, and it needs topping up. Fine for a long country drive, less so for a tight front in town.
Standard block paving on a normal sand bed is not permeable in planning terms. A little water goes through the joints, but the rule treats it as a solid surface, so over five square metres it needs a gentle slope to a lawn or border (or a channel drain into a soakaway) on your own land.
Why does permeable matter for planning permission?
Since 2008, in England, new or replacement paving in a front garden needs no planning permission at any size if the surface is permeable or porous, or if the rain runs off to a lawn or border to drain naturally on your own land. You need permission where more than five square metres of solid surface drains to the road. Conservation areas and listed buildings can have extra rules. A permeable drive passes that test on its own, with no channel drain to think about and no argument about where the water goes. Read do I need planning permission for a driveway for the rule in full.
Does a permeable drive help with flooding?
Yes, in two ways. On your own front it means no puddles, no ice sheet in January and no water running under the door. For the street, every solid front garden sends its rain to the same drains at the same time, and in a heavy storm that is what backs up. A drive that soaks up its own rain takes that load off. That is the reason the 2008 rule was written, and it matters as much on a small front in Bletchley as on a big one.
Would you rather just ask Terry?
A photo and a question on WhatsApp gets a straight answer, usually the same day.
Does permeable work on Milton Keynes clay?
This is the honest bit. Most of Milton Keynes sits on heavy clay, and clay does not soak up water quickly. A permeable surface on a thin base over clay fills up in a downpour and the water has nowhere to go. That does not mean permeable is wrong here. It means the drive has to be built for it:
| Layer | What it does on clay |
|---|---|
| Permeable surface (resin bound or permeable block) | Lets the rain in and keeps the top dry and clear of puddles |
| Open-graded stone base, 200mm to 250mm compacted | Acts as a reservoir. On clay this is where the storm is held while the ground catches up |
| Membrane over the clay | Stops the clay pumping up into the stone and keeps the base clean and open |
| Soakaway or overflow | Where the ground is very slow, a soakaway crate or an overflow to a border makes sure the base never fills to the top |
Terry checks how your ground drains on the visit rather than guessing, because a soakaway on the wrong clay is a bucket with no hole in it. Built this way a permeable drive on MK clay is no problem. Built on three inches of sand over clay, which is what a cheap quote gives you, it sinks and it floods. See why block paving driveways sink for what that looks like a few winters on.
Which houses does a permeable drive suit?
- Small fronts in older parts of town, like the semis in Bletchley and the terraces of Wolverton, where the whole front is going under paving and there is no lawn left to drain to.
- Fronts that slope towards the house, where a solid surface would send the rain at the front door.
- Anywhere in a conservation area where you want to keep the planning question simple. See driveways in conservation areas.
- Houses on newer estates where the developer put in a soakaway and a solid drive would overload it.
Where it suits less: a very large drive with a lot of heavy turning, where tarmac with a proper channel drain to a soakaway does the same job for less, and still meets the rule.
Is a permeable drive worth the extra cost?
Resin bound is the higher cost band of the three main materials, and permeable block costs a little more than standard block for the special blocks and the free-draining stone base. Against that you save a channel drain and its connection, you never fight a puddle, the planning question disappears, and resin bound needs only a sweep and a rinse. On a typical two-car front the difference is smaller than people expect once the drainage is priced in. I put both on the written quote so you can see it. The cost guide explains what moves the price, and block paving vs resin vs tarmac compares the three surfaces properly.
