On 10 May 2023, MCS published an update to The Solar Mounting (Product) Standard (MCS 012 v3.0). One of the changes to the standard was the expansion of scope to include mechanically attached and non-mechanically attached mounting systems designed for installation on flat roofs (≤ 10°).
Prior to this expansion of scope, installers utilised clause 5.5.5 in The Solar PV Installation Standard (MIS 3002) to ensure that, in the absence of certified flat roof mounting systems, products installed on a flat roof were compliant. Clause 5.5.5 states:
“Where there are no MCS 012 certified mounting systems suitable for a given installation, a custom designed mounting system may be used subject to the following being met: a) The system is compliant with current Building Regulations for weather-tightness, fire and wind resistance. b) The system designer and/or fixing supplier must confirm in writing that the final installation is in accordance with a) above and its instructions.”
Now that the Solar Mounting (Product) Standard allows for the certification of flat roof mounting systems, clause 5.5.5 in The Solar PV Installation Standard will no longer be acceptable as a means of compliance for flat roof installations.
Based on industry feedback, we are aware that several manufacturers are still in the process of gaining certification for their flat roof mounting systems. To support manufacturers in gaining product certification to the updated Solar Mounting (Product) Standard, and to avoid installers temporarily being unable to access certified products for flat roofs, MCS granted an extension of the use of clause 5.5.5 in The Solar PV Installation Standard (MIS 3002).
The current interpretation of clause 5.5.5 in relation to flat roofs was permitted until 10 August 2025, as of 20 June 2025 this has now been extended to 10 November 2025.
This will enable installers to register the installation of an uncertificated solar mounting system on the flat roof of a permanent building between now and 10 November 2025, subject to meeting the requirements stated within clause 5.5.5.