Reference
Standards Library
what the assessment is carried out against
Seven documents decide whether a roof can carry a solar PV array in the UK. This is what each one is, what it governs, and what it means for your building — written for the person buying the assessment, not for the engineer doing it. One of them is withdrawn, and still turns up in reports issued today.
BS EN 1991-1-4 and the UK National Annex govern wind actions on structures. What that means for a rooftop solar PV array, and why site exposure decides the answer.
02 BS EN 1991-1-3 Snow actionsBS EN 1991-1-3 and the UK National Annex govern snow actions. Ground snow load rises with site altitude, which is why a national average understates the load in the unsafe direction.
03 BRE Digest 489 Array wind upliftBRE Digest 489 provides net pressure coefficients for roof-mounted PV arrays. It is the UK reference for array uplift, and it fills a gap the Eurocode does not cover.
04 MIS 3002 V6.0 MCS structural requirementsMIS 3002 V6.0 became mandatory on 18 June 2026. When it mandates a qualified structural engineer, when a suitably competent person will do, and why every ballasted flat roof falls in the first group.
05 BS EN 1990 Basis of structural designBS EN 1990 sets out how actions are combined. It is the reason an array is never assessed on its own, but in combination with everything else the roof carries.
06 BS EN 1991-1-1 Densities, self-weight and imposed loadsBS EN 1991-1-1 covers self-weight and imposed loads. On a solar project it is the standard that catches the access loading a finished array quietly creates.
07 BS 6399 Withdrawn, and why it still appearsBS 6399-2:1997 was withdrawn in 2010. A structural report that still cites it is quoting a withdrawn standard, and that is a procedural defect a lender's technical adviser will find.