Ground mounted support systems

We’re planning on doing an extension to our house at some point in the not too distant future and are not 100% sure what the impact will be on the existing roof structure. Can you please provide details on the previous ground installed system with particular reference to the support structure?

From review of the SEAI code of practice for installers, it would appear that it is up to the installer to determine the suitability of the support structure as opposed to any particular building regulations. Perhaps the previous installers can offer guidance on this?

Below are extracts from the SEAI Code of Practice for the Installer.

4.3.4. Ground and Car-Port Mounting Systems - Installation
When considering a ground mounted or car port mounted PV system the Installer must assess the
below;
• The design and specification of the PV ground or carport mounting system shall consider the
requirements of Section 4.3.2 and

  • Strength and suitability of the ground area, soil conditions, stability, and risk of subsidence
  • Ground mounted systems over exposed soil/grass, shall have a minimum clearance of
    300mm from the ground level to the bottom of the solar PV modules to allow for
    vegetation/grass growth, and maintenance of same.
  • Cables from the ground mounted system to the dwelling shall be installed underground, in
    a suitable duct.

4.3.2. Roof Mounting Systems – Loading and Structure
When considering roof mounted PV system, the Installer must consider and assess the below.
• The design and specification of the PV mounting system for all installation types shall consider;

  • Building Regulations TGD A – Structure.
  • Building Regulations TGD D – Materials and Workmanship.
  • SR 50-2 “Code of Practice for Building Services Part 2: Thermal Solar Systems” and Agrément
    Certificates for Solar Thermal and Solar PV systems.
  • Site specific design wind and snow loads – derived from Eurocode-1 (and Irish National
    Annex).
  • Appropriate safety factors – derived from Eurocode-0 (and Irish National Annex).
  • Strength and suitability of the supporting structure.
  • Strength of the fixing – using fixing data from Eurocode-5 (for standard fixings).
  • Proposed mounting system and suitability for roof supporting structure and roof tile system.
  • Weather sealing of any impacted parts of the roof for mounting system and cable access.
  • Impact of any additional stress or strain on the overall roof structure and roof tile system,
    particularly over time and during multiple temperature changes.
    • The roof structure shall be checked to ensure it can withstand the imposed loads from the solar
    PV system. This should include a site inspection by a competent person.
    • Where there is any doubt to the suitability of the roof structure to withstand the imposed
    loads, a qualified structural engineer should be consulted. Reasons for consulting a qualified
    structural engineer may include, but are not limited to;
  • Signs of structural distress
  • Signs of post construction modification
  • Shallow roof pitch (<30°)
  • Roof design has potential for snow build up (e.g., dormers, valleys, parapets)
  • The roof is an unusual, non-standard, construction.
    • The Installer must retain documentary evidence of the calculations and assessment undertaken
    in the design of the mounting system showing that site specific structural and wind risks have
    been considered appropriately in the design.

I was part of the previous group and I am not the group coordinator so my comments are to be taken in that context. I am not sure if you have joined the second wave or if its a general question?

This forum is not really for providing detailed technical or design support. It’s more about grouping together interested parties to leverage some savings and sharing end user experiences.
Once you sign up to the group and express you preference for ground or roof mount installation, an installer will call and determine and advise what your best option is.

Personally I would prefer a roof mounted system if at all possible. Provided the roof is sound, there should be no issue mounting them securely. Being blown off by wind is probably the biggest risk to roof panels.

Hello Richie,

I’ll check with the man in East Clare who went with a ground mounted system to see which mounting system he used. I know that installers are a bit wary of going with DIY jobs as there is the issue of liability in case of a problem. The man I mention was going to take care of doing the civils, i.e. trench and a bit of concrete, himself and then the installer was to put the mounting system on that. / Colm

Thanks for the response Tom. I’m currently part of the second wave.

I was hoping to hear about what worked previously when someone from the first wave installed on the ground rather than the roof, as I know they were eventually able to do so. I’d prefer not to have to alter the system down the line if our future extension would impact on a roof installation. The best way I can see to do so is to install on the ground, where we have plenty of space.

Thanks Colm. Would be good to hear what worked before and then have a chat with prospective installers too, when the opportunity arises

The man in East Clare is going for the K2 system which you can see either on http://www.solartricity.ie or http://www.midsummer.ie