Solar carports on ground screws — foundations in car parks without excavation

A solar carport is a parking space canopy made of photovoltaic panels, the supporting structure of which is anchored to a paved surface — asphalt, paving or garage concrete. Ground screws allow the foundation to be installed directly through the asphalt layer into the subgrade overnight, without breaking up the surface and without a multi-day car park closure.

Specifics of building carports

Carport projects differ from greenfield installations (PV systems, timber buildings) in several key respects, which influence both the choice of machine and the work procedure.

Work on the paved area. The screw must drill through the asphalt or concrete surface and anchor into the sub-base layers and the soil beneath it. This requires a higher torque than screwing into open ground and often a DTH pilot hole through the hardest layer.

Confined space. Parking bays and aisles between the rows are narrow — the machine must fit between pillars, kerbs and existing street furniture. The width of the machine is therefore a key selection criterion.

Time pressure. Car parks for hotels, supermarkets or office parks cannot be closed off for weeks. Work is typically carried out in phases or at night so that the parking area is fully functional again by morning.

Noise and traffic near vehicles. The installation takes place in close proximity to parked (and potentially also passing) vehicles — it requires temporary signage, the clearing of the sector and coordination with the car park operator.

Higher wind loading of the structure. A carport is an elevated structure with a large surface area exposed to the wind (unlike a low PV mount on the ground) — the foundations must account for higher uplift and lateral loads.

Why ground screws for solar carports

No demolition, no rubble removal. The screw-driving machine drills through the asphalt or paving at the site of the screw — there is no need for extensive excavation or subsequent remediation of a large surface area.

Overnight installation. Ground screws can be loaded immediately after screwing in. The car park section can be closed in the evening and reopened in the morning — with a concrete foundation, the same section would be out of action for weeks due to curing.

Precise load capacity documentation. The telematics unit records the time and depth of each screw — providing data for the structural engineer and the car park operator, who is responsible for the safety of the structure above the vehicles.

Reversibility. In the case of rented parking areas (retail parks, hotel complexes), the carport can be removed after the end of the contract without permanent intervention in the surface.

Recommended machine for solar carports

For carport projects, we recommend two models depending on the surface type and project scope:

Glentor B80 — the primary choice for commercial carports on asphalt. The 8,000 Nm torque can drill through the asphalt surface and compacted sub-base, while the remote control allows work in close proximity to vehicles without the need for an operator on the machine.

Glentor A70 — suitable for smaller projects (hospitality, glamping, individual shelters), where a lower torque is sufficient and low weight (1,700 kg) and compact dimensions for entering confined sites are key.

Glentor C65 — an optional choice for concrete parking garage floors, where the combination of drilling and the MTB36 hydraulic hammer (900 J) can handle a harder concrete topping that the B80 could not break through without pre-drilling.

Carport installation guide — step by step

  1. Project preparation. A structural engineer will design the layout of the screws according to the carport's load-bearing structure, and will supplement this with an investigation of the road pavement composition (asphalt thickness, base layers) at the locations of the future points.
  2. Setting out and coordination with the car park operations. The surveyor will set out the positions of the screws, the operator will provide temporary marking and clearance of the sector — work is usually scheduled for night hours or outside opening hours.
  3. Drilling through the consolidated layer. The machine will drill through the asphalt or concrete surface at the location of each point, using a DTH pre-bore in the case of harder sub-base material.
  4. Screw insertion with telemetric recording. The screw drives into the base layers and soil to the prescribed depth, and the torque and depth are recorded for each point.
  5. Surface finishing around the screw and handover for the installation of the structure. Instead of drilling, it is finished off (grouting around the screw, or local asphalt repair if necessary), the sector can be reopened to traffic in the morning — the installation of the supporting steel structure and panels then takes place without disrupting the operation of the rest of the car park.

Comparison of Glentor models for carport projects

CriterionA70B80C65
Torque7,000 Nm8 000 Nm6,500 Nm
Mass1.7 tonnes2,480 kg3,050 kg - 3,250 kg
Hydraulic breaker❌ No❌ No✅ 900 J
Control—Long-distance—
Suitable forSmaller shelters, hospitalityCommercial car park, asphaltConcrete garage floors

B80 is the best choice if:

  • The project is a commercial carport on asphalt or a compacted surface (hotel, supermarket, office park)
  • A higher torque is required to drill through the hardened layer
  • Remote control required for working near vehicles

Case study: carport at a hotel resort

The operator of the hotel resort planned to cover part of the car park (approximately 250 spaces) with solar panels without the need to close the car park for a long period — guests needed continuous access to their vehicles.

The implementation team divided the area into sectors of approximately 30 to 40 parking bays. Each sector was closed for the night, the B80 machine drilled through the asphalt surface and installed screw anchors according to the design, and in the morning the sector was reopened to traffic. Telemetric data for each screw anchor served as a basis for the structural engineer and for the insurance of the structure above the parking spaces.

The entire foundation for the 250 parking spaces was completed within a matter of weeks, yet without a single day of the car park being fully closed — work was carried out exclusively in sectors during night-time hours.

TCO: carport without screws vs. with screws

CriterionConcrete foundationGround screws
Extent of surface interferenceExcavation and concreting over the entire foundation areaDrilling at a single point
Car park closing timeWeeks (incl. concrete curing)Nights by sector
Removal of rubble and surface remediationExtensiveMinimum (local watering)
Weather dependencyVysokáLow
Reversibility upon termination of the leaseLimitedVysoká

Frequently Asked Questions

Where to continue

Technical and normative requirements for trenching through asphalt and paving: Foundations on paved surfaces

Carports often complement larger solar PV projects: Solar parks on ground screws