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    Rooftop or Ground-Mount? Choosing the Right Solar Layout for Your Business

    Need Solar EngineeringAugust 5, 20267 min read

    The Trade-Off in One Paragraph

    Rooftop PV uses space you already own, needs almost no permitting, and sits close to your consumption - but it is limited by roof strength, roof age, shading from plant equipment, and a fixed maximum area. Ground-mount costs less per kilowatt at scale, produces more per kilowatt thanks to optimal tilt and row spacing, and can be expanded - but it needs land, planning approval and a longer grid connection route.

    Cost per Kilowatt

    At the same capacity, a ground-mount array is typically 10-20% cheaper per kWp above 1 MWp because installation is mechanised and the mounting system is standardised. Below roughly 300 kWp, rooftop usually wins because ground-mount carries fixed costs - fencing, access road, security, civil works - that do not scale down.

    Yield Difference

    In the Baltic climate, a rooftop array on a flat industrial roof is usually installed at 10-15 degrees tilt in east-west rows to maximise capacity per square metre. A ground-mount array is built at 30-35 degrees facing south. The result:

  1. Flat roof east-west: 850-950 kWh/kWp per year, but more kWp fits per m2 and the production curve is flatter across the day
  2. Ground-mount south 35 degrees: 1,050-1,150 kWh/kWp per year, with a sharper midday peak

    3. For self-consumption, the flatter rooftop curve is often worth more than the higher ground-mount total.

    Structural Reality Check

    Before any rooftop design, three things must be verified:

  3. Load capacity.: Baltic snow loads are significant. A modern industrial roof usually has margin; a 1990s panel roof often does not.
  4. Membrane age.: Under ten years of remaining life means the roof should be renewed first.
  5. Penetration strategy.: Ballasted systems avoid penetrations but add weight; mechanically fixed systems are lighter but must be sealed and warranted by a roofing specialist.

    6. Permitting and Land

    Rooftop systems within an existing building envelope are usually handled as a technical connection matter with limited building authority involvement. Ground-mount parks need land use clearance, environmental screening on sensitive sites, and a connection agreement that may involve a new medium-voltage line. Budget six to eighteen months for a park; six to twelve weeks for a roof.

    Operations and Maintenance

    Ground-mount is easier and cheaper to maintain: vehicle access, replaceable rows, simple cleaning. Rooftop maintenance needs fall protection, access planning and coordination with building operations. Factor this into the whole-life cost, not just the installation price.

    How to Decide

  6. You have a strong roof, high daytime load and want the fastest payback: **rooftop**
  7. You need more capacity than the roof allows, or you are selling to the grid or under a PPA: **ground-mount**
  8. You have a large parking area and customers or staff who charge vehicles: **solar carport**, which combines a roof-like self-consumption profile with ground-mount-style construction

    9. Most of our industrial clients end up with a combination: maximum roof coverage first, then ground-mount or carport to reach their target.

    Ask for a site assessment and we will model both options on your actual site.