As of 31 July 2026, the current MCS product standard for solar mounting on buildings remains MCS 012 Issue 3.0. It became mandatory on 10 May 2025. The grace period for products listed under the previous issue ended on 10 November 2025.
This article is written for mounting manufacturers, certification managers, and EPC technical teams who need a practical compliance map. It breaks MCS 012 into 17 gates. For each gate, decide: Pass / Evidence missing / Not applicable / Must remediate.
Source documents (download)
| Document | Link |
|---|---|
| MCS 012 Issue 3.0 (official PDF, MCS Certified) | Download MCS 012 Issue 3.0 |
| Affected product listing / grace-period notice | Affected Solar Mounting Product Listing |
| MCS 010 Issue 2.0 (factory production control) | MCS 010 |
| MCS 011 Issue 2.1 (testing requirements) | MCS 011 V2.1 |
| MIS 3002 Issue 6.0 (installation standard for solar PV) | MIS 3002 V6.0 |
1. Which mounting products fall inside MCS 012
MCS 012 is a product certification scheme for building-mounted solar PV mounting. It is not a general market-access licence for every UK solar structure, and it does not cover ground-mounted arrays.
| Product | In scope? | Notes |
|---|---|---|
| Pitched-roof above-roof (on-roof) systems | Yes | Modules sit above the existing covering |
| In-roof / roof-integrated systems | Yes | Rails, trays or modules replace part of the covering |
| Building flat-roof ballasted systems | Yes | Non-mechanically fixed roof systems |
| Flat-roof penetrating systems | Yes | Penetration of the waterproof layer usually triggers weathertightness tests |
| Roof hooks, rails, clamps, hangers, hanger bolts | Yes | Components or full systems may be certified; test paths differ |
| PV tiles and active PV roof products | Yes | MCS 005 also applies |
| Ground-fixed and ground-tracking structures | No | MCS 012 is limited to building roofs |
| Standalone flashings only around hooks | No | Explicitly excluded |
| Products that rely only on site-applied sealant for waterproofing | No | Factory seals, gaskets or inherent waterproof construction are required |
Under MIS 3002 Issue 6.0, MCS installations on pitched roofs are expected to use MCS 012 products in principle. Project-specific wind, structural, fire and Building Regulations design still sit with the installer and designer.
2. The 17 gates that must be cleared
Use this table as a live audit checklist. Status options for each gate: Pass / Evidence missing / Not applicable / Must remediate.
| Gate | Requirement | Evidence to prepare |
|---|---|---|
| 1 | Confirm the product is inside MCS 012 scope | Catalogue, intended use, roof types, installation photos or drawings |
| 2 | State whether the application is a full system or individual components | Exploded assembly, BOM, part numbers, load path |
| 3 | Identify certificate holder, manufacturer and all production sites | Legal entity, brand/OEM map, factory addresses |
| 4 | Appoint a competent Product Certification Body (CB) | CB operating to ISO/IEC 17065 with MCS 012 in scope (UKAS logo alone is not enough) |
| 5 | Agree product-family boundaries with the CB in writing | Variant matrix: material, section, holes, thickness, seals, connections, module sizes |
| 6 | Build a complete English technical file | Use and limits, controlled drawings, tolerances, materials, quality plan, reports, manuals |
| 7 | Pass MCS 010 factory production control (FPC) audit | Document control, suppliers, incoming/process/final inspection, calibration, traceability, NCR, complaints, training, change control |
| 8 | Test reports comply with MCS 011 | Accredited laboratory reports, or another path pre-approved and witnessed/assessed by the CB |
| 9 | Wind uplift performance acceptable | Formal uplift report, raw loads, failure modes, statistics, partial factors |
| 10 | Downward load on brittle coverings acceptable | Proof of no load into tiles/slates, or prescribed downward load tests |
| 11 | Weathertightness acceptable where required | Lowest declared pitch, worst-case roof and all interfaces |
| 12 | Sealing durable for service life | Seal materials, life evidence, compression, precise site-sealant rules if any |
| 13 | Fire performance where triggered | Fire report, classification, related PV module families |
| 14 | English installation instructions complete | Fixing counts, max spans, compatible roofs/modules, wind values, array limits |
| 15 | Annex B performance data complete | Wind, weathertightness, fire, roof types, minimum timber sizes, etc. |
| 16 | Traceability, marking and directory listing | Labels, batch rules, certificate number, MID / Product Directory data |
| 17 | Maintain certification after issue | Surveillance FPC, product audits, final-inspection checks, retest and change notification |
Supporting scheme documents: MCS 010 Issue 2.0 and MCS 011 Issue 2.1.
3. Which tests apply to which structures
| Structure type | Wind uplift | Weathertightness | Fire |
|---|---|---|---|
| Trapezoidal short rails / penetrating bases | Required | Required | Conditional |
| Hanger bolts | Required | Required | Conditional |
| Tile roof hooks | Required | Required | Conditional |
| Standing-seam clamps (non-penetrating) | Required | Usually not required | Case-by-case |
| Rails, connectors, end and mid clamps | Required | Driven by full system | Driven by full system |
| In-roof trays, PV tiles, integrated systems | Required | Required | Required |
| Flat-roof ballasted systems | Required | Required if penetrating | Conditional |
| Ground mounts | N/A | N/A | N/A |
Rails, clamps and connectors are not normally certified on single-component pull values alone. They are usually tested as part of a complete assembly.
4. Wind uplift: hard conditions
For mechanically fixed systems, as a minimum:
- Test principles follow BS EN 14437.
- At least one module is installed; where mid-clamps matter, at least two modules.
- Every component that resists wind in service enters the test.
- Rafters/purlins, timber sizes, fasteners and hole positions use the weakest configuration the manufacturer allows.
- Pitch is 45° ± 2°, or the maximum pitch declared by the manufacturer.
- Multiple hole positions: test the least favourable.
- At least three repeats per configuration.
- Characteristic resistance at 95% confidence per BS EN 14437:2022 Annex D.
- Full systems are declared in kPa; individual components in kN.
Design values divide by partial factors by failure mode:
| Failure mode | Partial factor |
|---|---|
| Deformation causing module detachment | 1.10 |
| Metal component fracture | 1.10 |
| Plastic component fracture | 1.25 |
| Self-drilling screws, rivets etc. pulled from metal | 1.25 |
| Timber failure or withdrawal from timber | 1.44 |
| Serviceability failure | 1.00 |
Also counted as failure:
- Module loose or insecure
- Fracture of mechanical parts
- Fastener withdrawal
- Maximum displacement over 75 mm, or exposure of the underlaying roof
- Residual displacement of roof members over 5 mm after unload
Flat-roof ballasted systems additionally need:
- Uplift path from module into the ballast system
- Sliding path: mechanical restraint, default friction coefficient 0.3, or measured friction
- Pressure coefficients: BRE Digest 489 defaults, or wind-tunnel/calculation to BS EN 1991-1-4 and the UK National Annex
- Any claim of aerodynamic relief must cover edge and corner turbulence
5. Weathertightness: hard conditions
- Membrane roofs at pitch not more than 10° with waterproof-layer penetration: BS EN 1928 Method A.
- Bonded to the membrane surface with no penetration: weathertightness testing is usually not required.
- Pitch greater than 10°: PD CEN/TR 15601 tests B and D.
- All roof-integrated systems must be tested.
- Above-roof products that penetrate continuous coverings must be tested.
- Products inserted into discontinuities (tiles, slates, etc.) must be tested.
- Test at the manufacturer’s lowest allowed pitch.
- Cover all representative joints and interfaces.
Test conditions:
- Test B: 13 m/s wind, 60 mm/h rain, stepped pressure difference
- Test D: no wind, 225 mm/h deluge, 2 minutes
- No enlargement of unprotected gaps: D required, B optional
- Enlarged unprotected gaps: B and D both required
- Pass criterion: performance not worse than an unaffected reference roof
6. Fire: when testing is triggered
All roof-integrated systems require fire testing.
Above-roof systems also require testing if any of the following apply:
- Installation enlarges gaps in discontinuous coverings (tiles, etc.).
- Organic material passes through roof gaps.
- Organic material replaces part of the covering.
For (2) and (3), exemption may be sought if the organic material meets either:
- Gross calorific value not more than 4 MJ/m², or
- Mass not more than 200 g/m² in the roof layout.
Test methods: BS 476-3:2004 or CEN/TS 1187:2012 Test 4. MCS 012 does not force one universal classification for every product, but the actual classification must be declared.
7. Brittle coverings and sealing
For hooks on tiles, slates and similar brittle coverings, one of the following must hold:
- No load is transferred into the covering; or
- Load is spread evenly without damage.
If load is transferred into the covering:
- Full-system downward test not less than 1.0 kN/m²
- Single hook not less than 0.25 kN
- Manual must state that hooks must not be stepped on or used as person-support points
Sealing:
- Products that rely only on site-applied sealant cannot be certified.
- Factory gaskets, seals or inherent waterproof geometry are expected.
- If site sealant is still needed, the manual must name brands or exact performance and method.
- Wording such as “use a suitable sealant” is not enough.
- The standard expects durability consistent with a typical solar system life; it does not itself fix a single 20- or 25-year number.
8. What MCS 010 factory audit examines
As a minimum, expect review of:
- Quality manager, roles and authority
- MCS product quality plan
- Internal quality review at least quarterly
- Version control of drawings, standards and manuals
- Approved suppliers and bought-in parts
- Incoming, in-process and final inspection
- Traceability of model, batch, time and place of manufacture
- Calibration of inspection equipment
- Non-conforming product isolation, disposition, CAPA
- Storage, transport, packing and product identification
- Complaint records and handling
- Competence and training
- Advance notice to the CB of changes to materials, suppliers, drawings, sites or process
- Product sampling and any required retests
ISO 9001 helps. It does not automatically replace MCS 010.
9. How to use this checklist on a live application
- Mark each of the 17 gates Pass / Evidence missing / Not applicable / Must remediate.
- For every “Evidence missing” or “Must remediate” item, assign an owner and a target date.
- Align product-family drawings with the weakest configurations used in wind and weathertightness tests.
- Keep English manuals, Annex B data and directory listing data in lockstep with the test reports.
- Treat any change to geometry, material, seal, fastener or factory as a potential re-notification to the CB under gate 17.
Downloads and references
- MCS 012 Issue 3.0, official PDF
- Affected Solar Mounting Product Listing (grace period)
- MCS 010 Issue 2.0
- MCS 011 Issue 2.1
- MIS 3002 Issue 6.0
Engineering reference only. Certification decisions rest with the appointed Product Certification Body and the current MCS scheme documents.
