Standards Library · 04
MIS 3002 V6.0
MCS structural requirements
The Microgeneration Certification Scheme technical standard for solar PV. Issued 18 March 2026, mandatory from 18 June 2026, applying to installations up to 50 kWp DC. It mandates a qualified structural engineer in named cases, and every ballasted flat roof is one of them.
What it is
MIS 3002 V6.0 requires the structure to be checked, before installation, to confirm it can carry the proposed array. The universal check, section 5.9.4, may be carried out by a suitably competent person.
The standard then names cases where that is not enough and a qualified structural engineer is mandatory: unusual roofs under 5.9.6 — hipped roofs, valley roofs, dormers, parapets, sub-30-degree pitch, and roofs showing structural distress — every flat roof ballasted system under 5.9.13(h), without exception, and non-standard mounting under 5.5.5(b).
It governs installations within the scope of the Microgeneration Certification Scheme. Work above the scheme's 50 kWp DC threshold is not covered by it at all, which is a common source of confusion on larger commercial schemes.
Why it matters for rooftop solar
The standard is misstated in both directions, and both are costly. Told it never requires an engineer, an installer walks into a ballasted flat roof job that always does. Told it always requires one, a client pays for engineering on a simple roof where 5.9.4 would have been satisfied.
If the array is ballasted on a flat roof, a qualified structural engineer is mandatory. 5.9.13(h) admits no exception, and flat roofs are exactly where ballast becomes the governing load. This is the single most commonly missed requirement in the standard.
Beyond the named cases, applying the engineer standard to all commercial work is our own position, not the regulation's. We separate the two deliberately, because a supplier who blurs them is selling on a compliance claim that will not survive being checked.
Because the standard does not specify the deliverable, two assessments can both be compliant and share almost nothing. That gap is what the Assessment Specification was written to close.