Accessible and Part M Parking
Firm, even, permeable parking bays and transfer zones that meet accessibility requirements without resorting to tarmac.
Why reinforcement matters here
Accessibility and permeability usually pull in opposite directions: the firmest surface is the least permeable. A gravel-filled grid, filled level and blinded, gives a firm and even surface suitable for wheelchair transfer while remaining fully permeable and visually appropriate for a landscaped setting.
Where this works well
At a glance
| Sub-base | 100-150mm MOT Type 1 |
|---|---|
| Infill | Angular 10mm gravel filled level and blinded with fines to give the firmest, most even surface |
| Typical loading | Cars and light vans, with a firm even surface for wheelchair transfer |
| Permeability | Fully permeable. Normally treated as a SuDS component in a drainage strategy. |
| Design life | 25 years, subject to documented installation. |
| Material | 100% recycled polypropylene, made in the UK. |
How it goes in
- Mark out the area and excavate to the depth of your sub-base plus the grid depth plus your infill blinding.
- Lay a woven geotextile across the formation, lapping joins by at least 300mm. This stops the sub-base and the subsoil mixing.
- Lay and compact the sub-base: 100-150mm MOT Type 1. Compact in layers rather than all at once.
- Blind the sub-base with a thin layer of grit sand and screed it level. This is what gives you a flat finished surface.
- Push-fit the grids together across the area, working from one edge. Cut around obstacles with a jigsaw or fine-tooth saw.
- Fill the cells: Angular 10mm gravel filled level and blinded with fines to give the firmest, most even surface. Work the fill in with a stiff brush so no cell is left hollow.
- Check the finished level. Nothing should stand proud of the cell walls, and no cell should be left under-filled.
Most installations are straightforward groundwork. The grids themselves push-fit together and need no fixings, adhesive or specialist tools.
Which grid depth?
The 30mm heavy duty grid, gravel filled and blinded. It gives the firmer, more even surface, which is the whole requirement on an accessible bay or route. Do not use grass infill here.
If you are between two options, take the heavier duty one. The cost difference across a typical project is small next to the cost of lifting and relaying a surface that was under-specified.
The mistake we see most often
Specifying grass infill on an accessible bay. Grass is not firm enough for wheelchair transfer, and this is the single most common specification error on these schemes.
Common questions
Is it genuinely suitable for wheelchair use?
When filled level and blinded with fines, it gives a firm even surface. Loose unconfined gravel is not suitable and this is the difference.
How should accessible bays be marked?
Contrasting infill within the grid cells gives permanent, paint-free marking that will not wear off.
What gravel gives the firmest finish?
Angular 10mm stone blinded with fines compacts tightest and gives the most even surface.
Does it meet Part M?
The surface characteristics support Part M compliance when correctly specified and installed. Confirm the full design with your access consultant.
How do we mark the bay permanently?
Contrasting infill within the cells gives a permanent layout that will not wear off the way paint does.
Does the route to the building need the same treatment?
Yes. An accessible bay connected to the entrance by loose gravel is not an accessible route.
Ask our engineer
Questions about depths, sub-base, edging or which system fits your project? Ask below.