What is the difference between standard, permeable and grass paving?
Standard block paving sheds water off its surface to channels and drains. Permeable paving lets water pass down through joints or openings into a porous base. Grass paving is a form of permeable surface that uses open cells filled with soil and grass, or with gravel, between solid concrete ribs.
| Type | How water is handled | Typical use |
|---|---|---|
| Standard block paving | Runs off the surface along planned falls | Drives, paths, yards, car parks |
| Permeable concrete blocks | Passes through wider joints filled with fine grit | Drives and parking where run-off must be reduced |
| Concrete grass grids | Soaks through open cells filled with soil or gravel | Parking bays, wheel tracks, occasional access routes |
In Spain, concrete grass grids are often called celosía de hormigón or celosía para césped. The name describes the open lattice of the block. Plastic grids exist as well, but this page concentrates on concrete systems, which we lay as part of our paving work and which keep their shape under the weight of parked cars.
Why choose a permeable surface on a villa plot?
A permeable surface reduces the volume of water leaving a paved area and can soften the look of a large parking space. It is useful where there is nowhere convenient to send surface water, or where an owner wants a greener drive rather than a continuous hard surface.
On hillside plots, concentrated run-off from a large paved drive can erode banks, overwhelm a single drain or flood a neighbour's land. Letting part of that water soak away close to where it falls spreads the load. On a flatter plot, a grass grid parking bay beside a lawn keeps the garden looking green while still giving a firm surface for an occasional car or a visitor's van.
Permeable paving is not a universal fix. On ground that does not drain, or where the area receives water from higher land, a permeable surface may simply fill up and hold water in its base. In those cases a standard surface with proper channels can be the better answer. Our guide to compaction and falls explains how surface water is planned, and the sister site's page on standing water and drainage deals with existing ponding problems.
How is a concrete grass grid laid?
Grass grids are laid on a compacted, free-draining base with a levelled bed of grit or crushed stone, set tightly together, bounded by firm edging and then filled. The filling, soil and seed or gravel, goes in last and is topped up as it settles.
- Mark out the area or the wheel tracks and excavate to the required depth.
- Install edging so the grids cannot drift sideways under load.
- Build and compact a free-draining granular sub-base, avoiding fine material that would clog.
- Spread and level a bed of grit or crushed stone over the sub-base.
- Lay the grid blocks tightly, tapping each one into place with a rubber mallet.
- Fill the cells with soil and seed, or with clean gravel, slightly below the top of the ribs.
- Top up the filling after the first rains and allow grass to establish before regular parking.
Filling level is a detail many people overlook. If the soil or gravel sits above the concrete ribs, tyres compact it and kill the grass; if it sits too low, the ribs become uncomfortable to walk on. Keeping the fill just below the ribs protects the grass roots while leaving a firm surface for wheels.
Should grass grids be filled with grass or gravel?
Grass gives a softer, greener finish but needs water and sunlight; gravel gives a low-maintenance, permeable surface that looks tidy all year. Where irrigation is limited, many owners choose gravel or reserve grass for areas that can be watered regularly.
Grass in grids competes with heat, reflected sun and tyres. Without regular watering it often struggles, and areas where cars park every day may never establish fully. Gravel fill avoids those issues and still lets water through, though it can be kicked out of the cells over time and needs occasional topping up. A combination is also possible: grass where cars rarely go and gravel in the daily wheel tracks. Whichever fill you choose, the cells should be topped up after the first heavy rains, once the material has settled.
Can permeable paving carry cars and vans?
Permeable blocks and grass grids can carry cars when the product is intended for that use and the base is deep and well compacted. Heavier vehicles depend on the product data and the base design, and should be discussed before the system is chosen.
The limiting factor is usually the base rather than the blocks. A permeable base has to be strong and open at the same time, which rules out the fine materials that make an ordinary sub-base dense. Firm edging matters too, because grids under turning wheels try to spread outwards. For mixed areas, a solid concrete block drive with grass-grid parking bays alongside can combine durability with a greener look; our page on concrete block paving covers the solid part, and kerbs and edging explains how the two are separated cleanly.
Do permeable surfaces need permission or special maintenance?
Permission follows the same rules as other outdoor paving: the procedure depends on the town hall, and minor works may fall under a responsible declaration in Andalusia. Maintenance is mainly about keeping joints and cells open so water can still pass through.
Leaves, dust and silt slowly clog the surface of permeable systems. Sweeping, occasional top-ups of joint grit or gravel and keeping soil from flower beds off the surface help them keep working. Grass-filled grids need mowing and watering like any lawn. The guide to permits and rules summarises the legal side, and the article on who block paving is for helps decide whether a permeable or a standard surface suits your plot better.
For cost, see block paving prices per square metre and the paving cost calculator. Grid fill, edging and the depth of the permeable base are the main items that differ from a standard paving quote. Send us a photo and the approximate m² – free, no-obligation quote.
Frequently asked questions
What is a concrete grass grid?
A concrete grass grid is a paving block with open cells between solid ribs. Once laid on a suitable base, the cells are filled with soil and grass or with gravel. The ribs carry the load while the filling lets water soak into the ground below.
Is permeable paving the same as porous paving?
The terms are often used loosely. Permeable paving usually means solid blocks with wider joints that let water pass between them. Porous paving can refer to materials that let water pass through the block itself. Both rely on an open base beneath to work.
Will grass grow in grids without irrigation?
Without irrigation, grass in grids often struggles, especially where cars park every day and the surface is in full sun. With regular watering and lighter use it can establish well. Many owners choose gravel fill instead, which stays permeable without needing water.
Can I park every day on a grass grid?
You can park on grids filled with gravel daily without much concern. With grass fill, daily parking in the same spot tends to wear the grass out. A layout with gravel in the wheel tracks and grass elsewhere often gives a better long-term result.
Why does a permeable base need special material?
An ordinary sub-base is dense and contains fine particles that block water. A permeable base must stay open so water can move into it and be stored, while still being strong enough to support the blocks. That is why it uses cleaner, more open graded material.
Does permeable paving work on clay ground?
On ground that drains poorly, water can collect in the base of a permeable system instead of soaking away. Sometimes an overflow or connection to a drain is needed, and sometimes a standard surface with channels is a better choice. The ground is assessed before deciding.
Do grass grids need edging?
Yes. Under turning wheels, grid blocks tend to spread sideways, especially at the edges of an area. Firm edging, such as kerbs set in concrete or a solid paving border, keeps the grids in place and gives a clean line against lawns or beds.
How do I keep permeable paving working?
Sweep away leaves and dust regularly, keep soil from beds off the surface, top up joint grit or gravel when it drops, and avoid spreading sand or cement on it. Clogged joints reduce how much water can pass through the surface.
Can I combine solid paving and grass grids?
Yes, and it is often a good solution. A solid block paved drive or path can be flanked by grass-grid parking bays, or grids can be laid only in the wheel tracks. Kerbs or a contrasting border separate the two surfaces neatly.
Are grass grids slippery?
Concrete ribs and wet grass can feel uneven or slippery underfoot, so grids are less suitable for main pedestrian routes. Gravel fill gives a firmer, more even feel. For paths used daily on foot, a solid paver is usually more comfortable.