A structural check settles one question, and only one: whether the roof structure is a candidate to carry solar modules as a permanent dead load, and where that load actually lands. It is a separate professional opinion from the electrical Certificate of Compliance, and in most South African homes it is the answer that limits the panel count long before an electrician is involved.
The roof space first, the paperwork second
I went up into my own roof space with a torch before I signed anything. Not because I knew what I was looking at, but because everyone kept describing my roof to me from the driveway and I wanted to see the thing they were describing.
Dust, heat, the geyser, insulation batts pushed into corners, and above all that a row of grey pine trusses. I could see the webbing, the diagonal bracing, the purlins running across, the underside of the covering. What stuck with me wasn't the timber. It was how much of my roof is air. It is a lattice, not a slab, and every kilogram of module and rail has to find its way through that lattice down to the walls.
The installer stood in my yard and told me the roof was fine. He had walked on the tiles. Walking on a roof tells you about the tiles and about his balance. It does not tell you what is holding them up.
Two houses, same roof area, different answer
What made me stop trusting the driveway conversation was a neighbour's house with the same footprint as mine and a different answer. Same approximate roof area. His array got trimmed. Mine didn't, or not for the same reasons.
Truss spacing and span do that. Two houses with identical roof areas can carry very different panel counts, because the load has to travel from the modules, through the rails, into the purlins or the truss top chord, along the truss, and into the wall plate. How far apart the trusses sit, how far they span between supports, and whether anything has been altered since the house was built all change the answer. South African roof structures are generally designed for the roof covering plus wind and rain. Spare capacity exists, but it is not a large unused allowance sitting there waiting for an array.
If you look up at your own timber you may find a fabricator's stamp. That is useful. It tells you who designed the trusses originally, which is usually where a structural question starts.
What the structural question is actually made of
Three things get mixed together and they shouldn't.
The covering. Older lightweight coverings, fibre-cement sheeting and thin sheet metal among them, are the ones most likely to need a professional structural opinion before anything goes up. Age and condition matter as much as type. A covering that has been walked on for thirty years is not the covering that was designed.
The structure under it. This is where the real answer lives. The question is not how many kilograms the roof can hold in the abstract. It is where the point loads land, what carries them, and whether the bracing and the tie-downs are still doing what they were meant to do. Dead load is one thing. Load that moves around in wind is another.
Uplift. In coastal and high-wind parts of the country, wind uplift is a documented design consideration, and it is the reason installers reduce module counts near roof edges. That has a consequence homeowners don't expect: the panel-able area of a roof is smaller than the roof area. Edges and ridge zones are where arrays get trimmed, and that trimming happens before any electrical design is finalised.
Flat concrete roofs work on a different structural principle from pitched roofs. Modules typically sit on frames or on ballast, and both change the load path. Ballast adds weight by definition, and frames concentrate load at fewer points. It also changes the usable area, because the perimeter zone behaves differently and usually wants to stay clear.
Underneath all of it runs a servicing question. Tiled roofs and sheet roofs are walked and serviced differently. Whoever climbs up in five years to chase a loose connection or a failed module is going to be standing on your covering. A cracked tile on every visit and sheeting that flexes underfoot are not the same maintenance reality, and that difference belongs in the structural conversation, not in a footnote.
Which professional signs which question
This is the part a quote tends to blur.
A Certificate of Compliance, issued under SANS 10142-1, is a statement about the electrical installation: the DC and AC sides, earthing, isolation, labelling. It says nothing about whether your roof can carry the array. An SSEG application under NRS 097-2-1 is a statement about how your system behaves on the municipal network, protection settings, inverter behaviour, the meter. Also nothing about your roof. The structure is a third question with a third answer, and it needs someone who carries professional responsibility for the building side of it.
So when a quote has a line that reads something like "structural" or "engineering certificate included", the question to ask is narrow and specific: which document do I receive at the end, and who signs it? If the answer is a workmanship warranty, that is not a structural opinion. If the answer is "we've done hundreds of these roofs", that is experience with a pattern. Patterns are genuinely useful. They are not an opinion about your trusses, and nobody is carrying liability for your roof because they have seen similar ones.
A "yes, with conditions" answer is often the most valuable one you can get, because the conditions are design constraints you can hand straight to whoever draws the layout.
Why the structural answer has to come before the layout
The structural answer changes the array. How many modules, where they sit, how far from the edges, on which plane, or whether the answer is a smaller array, a different mounting approach, or a ground mount instead.
Array layout then sets the string design, the voltage, the inverter's input range, the DC cable route. That chain is what the CoC ends up certifying. If you settle the layout first because the quote says so, and the structural answer trims it later, you redo the electrical design. The paperwork follows the roof, not the other way around.
What I'd say to someone standing where I stood
I can't tell you from here whether your roof is a candidate. Nobody can, from a photograph and a description. What I can tell you is which question you are buying, and from whom.
Not every roof needs a formal structural opinion. Sometimes the fabricator's documentation and a proper inspection settle it. Sometimes the honest answer is a smaller array. Sometimes it turns into a covering problem first, and the structural question becomes a roof-maintenance question before it becomes a solar question.
The one thing worth holding onto: nobody's compliance paperwork covers your roof. The CoC covers the wiring. The SSEG approval covers the connection. The roof is the part everyone assumes somebody else checked.
