LANDBLOCK
LANDBLOCK is a range of ballasted, non-penetrating base elements for mounting photovoltaic modules on a flat roof. Each pre-formed base sets the module tilt and holds its ballast inside the element itself, so the array resists wind uplift without drilling through the waterproofing. Assembly is quick and needs few loose parts, and the range works with standard rail profiles and flat roof modules. Guide
Related flat roof categories
LANDBLOCK: a pre-formed base instead of a built-up frame
A LANDBLOCK style system replaces the loose collection of feet, struts and separate ballast slabs with a pre-formed base element that already carries the geometry of the installation. The base defines the module tilt, seats the module or the rail that holds it, and takes its ballast inside the element rather than on top of it. The load is spread over a broad footprint and the underside sits on the roof covering through a protection layer, so the system stays non-penetrating: the PVC-P, EPDM or bitumen membrane is never pierced. On site the benefit is speed and repeatability, since every position is set out the same way and the ballast per base comes from the wind calculation.
FROM THE FIELD
"Base systems are fast, and that is exactly where teams get careless. The ballast plan is still per position, not one number for the whole roof, so the perimeter and corner bases get filled differently from the field. Fill them to the plan before the modules go on, because topping up under a finished array is miserable work."
Ladislav Proc · Mounting systems specialist, ONSA Plus
How to choose and specify a LANDBLOCK system
Three site facts decide whether a ballasted base system is the right answer, and all three belong in the enquiry rather than in a surprise on delivery day: the permitted additional roof load, the type and condition of the membrane, and the wind zone with the building height and terrain. Everything else follows from those.
Show the full guide Close the guide
Check before you order
A base system is only usable if the building can carry the ballast the wind calculation demands. Confirm these points first and the rest of the specification is straightforward.
- Permitted roof load: the additional load in kg/m² the structure may take, confirmed by a structural assessment. Snow load draws on the same reserve, so it has to be counted in.
- Membrane type: PVC-P, EPDM, TPO or bitumen. The membrane decides which protection layer is approved and whether direct contact with other materials is allowed at all.
- Wind zone and building data: wind zone, building height, terrain category and parapet height feed the uplift calculation that sets the ballast per base.
- Module dimensions: the base is designed around a module format and clamping position, so panel size and frame height must be settled before ordering.
Tip from practice
Agree the separation layer with the roofer in writing. Most roofing warranties name the mat or fleece that may sit between structure and membrane, and a base placed straight onto PVC-P without it can void that warranty even though nothing was drilled. Order the mats with the roof accessories.
Base system or rails with separate ballast
Both approaches are ballasted and non-penetrating, and both are sized by the same wind calculation. The difference is where the weight sits and how much assembly happens on the roof.
| Property | Pre-formed base | Rails with separate ballast |
|---|---|---|
| Tilt | Fixed by the moulded element | Set by adjustable supports and struts |
| Ballast placement | Inside the base element | Blocks or trays on the rails or feet |
| Parts on site | Few, largely pre-assembled | More components and fasteners |
| Best suited to | Clear rectangular roofs, repeated layouts | Awkward shapes, obstacles, mixed tilts |
Swipe the table to the left
Frequently asked questions about LANDBLOCK
What is a LANDBLOCK mounting system?
It is a ballasted flat roof system built from pre-formed base elements. Each base sets the module tilt and holds its ballast inside the element, so the array resists wind uplift by weight alone and the roof waterproofing is never penetrated.
What do I need to check before ordering?
Three things: the permitted additional roof load from the structural assessment, the membrane type on the roof, and the wind zone with the building height and terrain category. Those decide whether a ballasted system is viable and how much ballast each base needs.
Does the system damage the roof membrane?
Not when it is specified correctly. The bases sit on the roof covering through an approved protection layer that spreads the load and prevents abrasion or incompatible material contact. Match that layer to the membrane and confirm it with the roofer.
How is the ballast quantity decided?
By the wind uplift calculation for that specific roof, position by position. Bases in the edge and corner zones carry more than those in the field area, and the total must stay within the permitted roof load. It is never one figure applied everywhere.
Can I use it with any solar panel?
Only within the module sizes and frame heights the base is designed for. Settle the panel format first, then confirm the base and clamping arrangement against it. The same applies to any rail profiles that carry the modules across the bases.
How does it compare with a rail based ballasted system?
Both are ballasted and non-penetrating. A base system assembles faster and keeps the weight inside the element, which suits clear rectangular roofs. A rail based ballasted system has more components but adapts better to obstacles, mixed tilts and irregular roof shapes.
Confirm the permitted roof load, the membrane type and the wind zone before ordering a ballasted system.
About ONSA Plus
Why installers across Europe order ballasted systems from us
ONSA Plus is a European B2B distributor of photovoltaics, battery storage, heat pumps and EV charging stations. In our own EU warehouses we keep over 1,500 products from 25+ brands, including Huawei, Solis, SolaX and Dyness.
We are not just a trading company. We design and service energy systems ourselves, so we answer questions on ballasted flat roof systems and membrane protection from engineering practice, not from a catalogue. You handle a warranty claim directly with us and you buy per job.
