Guide · Structure
Can my roof support panels?
It's the objection that comes right after the price: "what if my roof can't take the weight?" The good news is that a solar panel is much lighter than you'd think — the real question isn't the weight itself, but the nature of your roof and the condition of its load-bearing structure. Here's how to make sense of it, roof by roof.
The real weight of a solar panel
A current high-power photovoltaic panel (the Canadian Solar/Jinko 710 Wc modules we install, for example) weighs, according to its manufacturer spec sheet, about 37.8 kg for a surface of about 3.11 m² (2,384 × 1,303 mm), or an order of magnitude of about 12.2 kg/m² for the module alone, before adding the mounting structure (aluminium rails, hooks or concrete ballast depending on the roof). With structure included, a surface-mounted installation on a frame or concrete slab generally stays on the order of 14 to 17 kg/m² spread over the whole covered surface — a weight comparable to a layer of gravel or a few centimetres of standing water, far below the loads a roof is designed to withstand (wind, maintenance, sometimes snow depending on the region).
This figure is a useful order of magnitude to reassure on the principle, not a structural validation: the question that really matters is whether your specific roof, in its current condition, is designed to carry a permanent distributed load — and that's strictly a matter of roof type and load-bearing structure, not the number of panels.
Roof by roof: what changes
Solid concrete slab (typical Moroccan terrace)
The vast majority of Moroccan residential roofs are solid concrete slabs, designed to bear far more than pedestrian foot traffic. This is the most favourable case: the weight of a solar installation (panels + weighted or bolted mounting structure) stays well below its original load-bearing capacity. A visual check of the slab's condition (cracks, water infiltration, exposed rebar) is still worthwhile before any install, but a full structural calculation is rarely necessary on a sound slab.
Tile roof
Tiles themselves don't bear the weight of the panels: mounting is done on the frame, via hooks that pass through the roofing and anchor onto the rafters or purlins. The question isn't therefore "will the tile hold?" but "will the frame under the tile hold?" An old or already-loaded wooden frame (solar water heater, previous overload) deserves an opinion from a carpenter or structural engineer before installation.
Corrugated sheet or steel deck
Common on agricultural sheds and light industrial buildings. The sheet alone doesn't support the weight of a panel: mounting goes through the underlying metal or wood purlin, originally sized for wind and occasional maintenance, not for a permanent distributed load. On this type of roof, a structural opinion is the rule rather than the exception, especially over large spans.
Waterproofed flat roof (bitumen, membrane)
Ballasted installations (no drilling, panels mounted on trays weighted down with concrete blocks) avoid piercing the waterproofing, but add concentrated weight on specific zones rather than distributed evenly. On a flat roof, you mainly check the load-bearing capacity of the slab under the waterproofing and the distribution of load points — not just the total weight.
When is a structural check needed?
Certain signals call for a professional opinion (carpenter, structural engineering firm) before any installation, whatever the roof type: visible cracks on the slab or load-bearing walls, visible sagging or deflection of the frame, an already old roof (beyond 30–40 years with no known renovation), the presence of an existing overload not originally planned for (solar water heater, tank, planting), or a sheet/steel-deck roof over a large span. Outside these cases, on a standard residential concrete slab in good condition, the weight of a solar installation doesn't constitute a risk factor in itself.
That's why our study always starts with a visit or photos of the roof before any pricing: we look at the real condition of your roof before talking about kWc.