Clearance height is the first dimension a canopy designer fixes and the one buyers think about least. It sets the column height, the wind load on the foundations and, in England, whether the project can use a permitted development route at all. A canopy over staff parking and a canopy over a delivery yard are not the same project with a different number on the drawing.
This is a companion to our solar canopy design page, which lists the dimensions and loads a specification should state, and to the planning permission guide, which sets out the consent routes. Here we take one question: how tall does the canopy have to be, and what does that decide?
Start with the vehicles, not the structure
The clear height under a canopy has to cover the tallest vehicle that will use the bay, with a margin for the underside of the beams and any lighting or cabling. Our design page gives the working figures we use as a starting point:
| Bays used by | Typical minimum clear height |
|---|---|
| Passenger cars | 2.4 m |
| Accessible bays and service vehicles | 3.0 m |
| Vans and high-roof vehicles | 3.5 m |
| HGV delivery access | 4.5–5.5 m |
Those are planning figures for early design, not a substitute for measuring your own fleet. High-roof vans, minibuses with roof equipment, refrigerated vehicles and refuse trucks all exceed a car-park default. If you do not know what visits the site, count them: a week of gate logs or a walk round at delivery time answers it faster than any rule of thumb.
The figure that matters is the clear height under the lowest structural member, not the height of the columns, and it must hold across the whole bay including the sag of a long beam and any cross-bracing.
Where Class OA’s 4 m limit bites
In England, Class OA of Part 14 of the General Permitted Development Order, in force since 21 December 2023, makes a solar canopy permitted development within an area lawfully used as off-street parking, other than parking for a house or a block of flats. It is a prior approval route, and no part of the canopy may be more than 4 metres above ground level. Scotland’s Class 9M also sets 4 metres, measured from the parking surface, with 3 metres for any other part of the development.
That cap is a limit on the top of the structure, not the clearance underneath. A canopy that sits at a shallow tilt has to rise above its clearance height by the depth of the beams, the panel deck and the slope across the bay. Put the two together and the arithmetic is unforgiving:
- A canopy with a 2.4 m clear height can usually keep every point of its structure under 4 m, even over a wide bay.
- A canopy with a 3.5 m clear height for vans leaves little more than half a metre for the beams, the deck and the pitch. Whether it fits depends on the span, the tilt and the design, and it needs checking drawing by drawing.
- A canopy with a 4.5–5.5 m clear height for HGVs cannot be under 4 m at any point, because its own clearance is already above the cap.
The consequence is simple. A canopy designed for lorry access falls outside the Class OA height limit and needs a full planning application, with the longer timeline, the fee and the officer’s discretion that implies. Nothing is wrong with that route, but it should be chosen with eyes open, because it changes the programme.
Three ways to handle a mixed car park
Many commercial sites have cars and vans in the same car park and lorries at one end. The usual responses are:
- Canopy the cars, leave the yard. Cover the staff and visitor bays at low clearance, keep the lorry route open and put the generation where it is easiest to consent. This is the lowest-risk route in England and often the best value per pound, because bays under 3 m cost less in steel.
- Canopy to van height and check the 4 m. Possible on some layouts. Ask the designer for the maximum height of any part of the structure on the elevations, not only the clearance, and keep a tolerance for the finished levels of the surface.
- Go for HGV clearance and a full application. Justified where the yard is the only large open area and the energy load is on site. Budget the planning cost, the time and the risk of conditions. Our cost guide covers the planning line.
What height does to the price
Height is not free. Higher eaves mean taller columns with a larger bending moment under wind, so heavier base plates and bigger foundations. Our design page notes the effect directly. The rough rule is that the structure costs more per bay as clear height rises, and the spread between a car-height and an HGV-height canopy can be large. Ask any supplier to price the same layout at two heights so you can see the step.
Height also interacts with the structure type. A cantilever canopy keeps the bay free of columns on one side, which matters for turning vehicles; a mono-pitch canopy is the simplest form; a T-frame canopy puts a central column between two bays. Each has a different relationship between column position, clearance and total height, so choose the structure and the height together. The structure types guide compares them.
Questions to settle before you brief a designer
- What is the tallest vehicle that will use each bay, and how often?
- Is the 4 m cap in play in England, or in Scotland under Class 9M?
- Are there low obstacles on the route in, such as barriers, gantries or tree canopy?
- Will EV charging or lighting be fixed to the structure, which lowers the usable clearance?
- Who checks the finished levels against the elevations?
Answering these first avoids the commonest late surprise: a canopy that passes prior approval and then turns out too low for the delivery fleet.
Where this fits in the wider picture
Clearance is one input to a solar panel canopy specification, alongside bay width, wind and snow loading, the foundations and the grid route. If you want the sums run for your own layout, you can request a free feasibility assessment. We reply by email with indicative capacity for the car park and the likely consent route.
Planning figures checked against our planning and design pages on 18 October 2026. Planning rules change and local authorities differ; confirm the position with the local planning authority before relying on permitted development.