Is there a way to do this that doesn’t cost the Earth?
In 2015 the RHS reported that 3 million gardens had been paved over in the past ten years, decreasing plant cover by 15%. Replacing green spaces with hard concrete has a devastating impact on our environment because:
- paving causes water run-off into streets leading to increased flooding
- wildlife habitats are destroyed
- we lose the trees, grasses and plants that provide shade, cool our towns and trap CO2 and other pollutants
- paving warms up during the day and releases heat at night, raising urban temperatures
- CO2 is released when concrete is produced
As the climate crisis worsens, heavy rain and flash floods will be more common. See also (Why concrete + rain = flash floods)
Are all drives bad for the environment?
Gardens and green spaces reduce temperatures, trap pollution and reduce the risk of flooding. Paved drives increase pollution, global warming and flooding. So paving over your front garden is not good for the environment, but some options are better than others. The list below gives you a brief summary of some of the options for fixing your drive, but first, some things you should consider:
Are you increasing the risk of local flooding?
- A drive that is made from permeable materials will allow water to pass through into the ground beneath, reducing the risk of water run-off.
- If your drive is made from impermeable materials, you need to have some drainage systems in place. Incidentally, you need planning permission before laying impermeable driveways bigger than 5m2.
To what extent are you increasing pollution?
- Drives that are made from natural, or recycled, materials are less harmful than materials which generate, or require, large amounts of heat in production, such as concrete, and tarmac?
Are you destroying wildlife habitat?
- Try to leave as much space as possible for trees, shrubs, flowers or grass.
Can you use local resources?
- When possible, source local materials that haven’t been transported thousands of miles to reach you.
- What is it? crushed stone and aggregate mixed with tar/bitumen.
- Is it permeable? No, although there are some, more expensive, permeable variations of asphalt.
- How green is the material? It’s made from by products of coal/petrol and burning tar produces toxic chemicals, so low green score.
- What is it? a mixture of cement (lime + Silica + Alumina + magnesium + sulphur + iron oxide + calcium sulphate) mixed with water and then added to aggregates such as sand and gravel.
- Is it permeable? No.
- How green is the material? To make concrete requires lots of heat and water. Producing concrete generates large amounts of carbon emissions (2.8 billion tonnes of CO2, or between 4-8% of the world’s total emissions). Some greener concretes are available but is your contractor using them?
- What is it? Also called pervious or porous concrete. Contains much less (if any) sand than ordinary concrete. This allows voids to form between aggregates so that water can pass through to the ground.
- Is is permeable? Yes
- How green is the material? Better than solid concrete. Can be made from crushed/recycled concrete.
- What is it? Also known as brick paving, the blocks are made from crushed stone, sand, cement etc and arranged in patterns to form a solid surface.
- Is it permeable? Generally No, but there are permeable varieties. the blocks may be made from porous concrete, or they may have irregular edges which leads to larger gaps between them, providing more drainage. Check the materials used as well as the way they are being laid.
- How green is the material? This will vary. Blocks made form recycled materials, such as crushed concrete are a greener option.
Permeable resin bound driveway
- What is it? aggregates coated in polyurethane resin to create a tough, smooth surface. It has become very popular in recent years.
- Is it permeable? Yes
- How green is the material? Polyurethane, as a plastic, is oil based so not particularly green.
- What is it? Mesh system that supports weight of vehicle and allows grass to grow through. Typically a layer of sand beneath a plastic mesh, which provides structure and also protects grass roots. Grid systems can also be used with gravel.
- Is it permeable? Yes
- How green is the material? The mesh is often made from 100% recycled plastic, but do check. Grass, one of the main components, is green ; )
Natural stone pavers
- What is it? Paving made form natural materials that don’t require manufacturing processes.
- Is it permeable? Some natural stones are more porous than others. Granite and quartz are not very porous, whilst sandstone is. Ensure you leave adequate gaps between blocks to allow water to drain through.
- How green is the material? Excavating/mining raw materials releases CO2 and depletes our natural resources, so if possible use reclaimed stones. The more local the material, the greener it can be. Consider also using reclaimed bricks.
- What is it? Loose stones or rock fragment. One of the cheapest options, but not great on a slope. Larger gravel is difficult for pushchairs, and wheelchairs, but a wheelchair doesn’t need the full width of a standard driveway, so consider including a path made from alternative materials, or use a grid/mesh for a small section and fill with gravel – see eco-grid below.
- Is it permeable? Yes
- How green is the material? Greener than materials that have to be manufactured. Choose local gravel if possible. You can also buy gravel made from recycled materials, such as eco-aggregates.
Option: keep your existing drive
This maybe the greenest option for you. Think carefully before digging up an existing driveway just to replace it with a ‘more environmentally friendly’ option. Consider:
- can the materials be re-used elsewhere or will they be going to landfill?
- If the drive is impermeable, can drainage be added?
- If the drive has holes or an uneven surface, can it be repaired?
- Can part of the drive be removed to allow space for plants? There are always corners that cars can’t reach.
Tips from B & Q on adding or improving drainage.
Tips for greening your front drive
- make as much space for plants as possible, fill the corners with plants, fill the walls with climbers, add pots if you have no soil
- use natural, reused, or recycled, permeable materials
- ensure there is adequate drainage
- try to fix before replacing
Businesses offering green options for driveways
Bradstone were recommended to us as they tick several of the eco boxes. Their website includes a ‘Find an installer’ search box, so you can select a local contractor to do the work, as well as a ‘Find a stockist’.