Will Your Car Park Take the Weight of a Solar Carport?

The load is wind, not panels

The intuition is that a solar carport is heavy because of the panels. It is not: the modules are a small part of the load. The governing case is wind uplift on a large, shallow, elevated surface, combined with snow load, both taken from the Eurocodes for the specific site. That is why a canopy in Glasgow and an identical one in Portsmouth need different foundations — and why a design that has not been loaded for the actual location is not a design.

Why the ground investigation comes before the quote

Foundations are the line item that varies most between two otherwise identical car parks. Made ground, a high water table, or an old landfill or colliery site changes the foundation type and can change it by a large multiple. A ground investigation before pricing converts the biggest unknown into a number; skipping it moves that risk into the build as a variation.

What is under the tarmac matters as much as what is in it

Car parks are full of buried services, attenuation tanks and drainage runs, and a canopy column cannot land on any of them. A utilities survey sets the column grid, and the column grid sets the bay layout, which is why the structural and parking layouts have to be designed together rather than in sequence.

Drainage is a planning issue, not just an engineering one

A canopy creates a new impermeable area over ground that was already impermeable, but it concentrates the runoff into fewer discharge points. Authorities ask for a drainage strategy on prior-approval submissions for exactly this reason, and a thin answer is a common cause of delay on a route that otherwise takes 56 days to determine. The array sizing that sits on top of those foundations is covered on car park solar panels. The structural and specification detail behind all of this sits on the solar carports page.

Related reading: what to specify in a carport · capital allowances on a solar carport · the PV layer for a car park.