When we bought our strange renovation project (a 1700s stone cottage with a dated 1970s extension) we had firm energy-efficiency goals that we wanted to achieve.
The first port of call was insulating the walls, solving the damp issues and to make the home less wasteful. The second was to replace our 30-year-old oil boiler with a renewable solution. And the third was to install solar panels on our flat roof to further reduce our energy bills.
Why did we want solar panels in the first place?
Here is our flat roof when we first bought the house - we have since swapped out the windows after a lengthy planning process.
The 70s extension section of our house has a flat roof that faces north west, and with the help of some ballast boxes positioned correctly, we hoped we could pick up the light needed for solar panels to collect energy almost all day. From a planning consent point of view, it also helps that the flat roof is at the back of the house so the panels would be mostly hidden from street view.
This is our second renovation project and one that we are able to stay in long-term so investing in infrastructure such as solar panels, insulation and renewable heating seemed like a no-brainer to me. Solar panels would reduce our bills over the course of the years we reside here, eventually breaking even in around 8/9 years, depending on their cost.
However, when we were drawing up our planning permission technical drawing with our architect, he suggested that it may be better to put in a separate application for the solar panels, independent of the one for the new windows, render and driveway we were seeking permission for. Speaking shortly after with our structure engineer, they also suggested waiting a few years before looking to install the panels would be best, but for entirely different reasons to the architect.
What were the potential issues with installing solar panels from the architect’s perspective?
Firstly, our architect’s concerns were for our planning permission application. In Conservation Areas many remedial works that usually fall under Permitted Development in other areas need approval from the local planning department. Unfortunately, this meant a lot of our external renovations were tied into the planning process.
I had assumed that getting planning permission for solar panels would be as simple as adding them to the proposed plans for the other work, but our architect commented that adding too much to the proposal meant that there might be a higher risk of getting a refusal from the council, with all of the proposed changes being rejected as a result. And that's definitely not what we wanted.
His solution was to apply a ‘first batch’ with the things that needed remedying sooner rather than later and, after a few years, apply separately for the solar panels alone.
‘In most standard properties, solar falls under permitted development,’ begins Martyn Fowler, founder of Elite Renewables. ‘In Conservation Areas and especially with Listed Buildings, things become more sensitive. Visibility from the street, impact on the character of the building and the type of mounting system all come into play. Sometimes it makes sense to separate applications if you're planning a larger renovation project so one element does not jeopardise the other. That said, every local authority interprets guidance slightly differently.’
A ballast system will likely be needed when installing solar panels on a flat roof, which can add to their weight. So your roof will need to be in good condition
‘In conservation areas and for listed buildings, the local authority has a statutory duty to give special regard to preserving the building and its setting, or the character and appearance of the wider area,’ agrees Cerys Atchinson, Chartered Town Planner at Planning By Design. ‘This means even relatively minor additions can receive closer scrutiny than they would elsewhere.’
Very few properties in our village have solar panels, so we weren’t overly optimistic if we did take the gamble of adding them to our planning application, and looking back at the nearly seven month process of simply agreeing on the style of replacement windows, we decided not to further complicate matters.
Trained as a plumber and electrician, Martyn founded sustainable design and techinical installations company Elite Renewables.
With her Masters in Urban and Regional Planning, Cerys now works on minor and major planning developments with Planning by Design, a team of planning consultants and architects.
What were the problems from a structural engineering view?
Another spanner in our building works came from our structural engineer when we casually discussed that we would like to invest in solar panels on our flat roof. After inspection, he concluded that the current material covering the roof would be in need of replacement in the next few years. That meant that installing solar panels on the decaying roof fabric would be completely nonsensical, but it’s an issue that often trips people like us up.
‘You need to look at the condition of the roof. If the covering is near the end of its lifespan it will need to be replaced first,’ says Martyn Fowler. ‘There is no point installing solar on a roof that will need redoing in a few years.’
Logically too, if we waited until our covering if due a replacement, we could also diagnose if the roof structure is in need of reinforcements. As we have a flat roof, we could use a mounting system or ballast boxes to position the solar panels to an optimal position, but they naturally increase the weight of the panels and therefore additional support would be needed.
‘When considering the installation of solar panels, it is important to assess the suitability of the roof structure,’ explains Ezgi Cebi, Architectural Designer at Planning by Design. ‘If a significant number of solar panels are to be installed, or if there is any concern that the existing roof structure may be old or insufficient to support the additional load, it is advisable to consult a structural engineer.’
‘Where the roof is flat, panels are usually mounted on angled support frames to achieve an appropriate orientation toward the sun,’ she continues. ‘There are proprietary mounting systems available that allow the inclination to be optimised.’
With so many other elements to our renovation, and a budget to manage, replacing what is currently a functioning roof seemed silly, so we followed the engineer’s advice and have decided to wait a few years. Plus, replacing the roof covering will add around £6,000 to our solar panel costs, so we need time to address more urgent issues before we prioritise these funds for solar panels.
Ezgi has experience drawing up planning drawings and interior design renders for a wide variety of projects at Planning by Design.
So, where does that leave us?
Unfortunately, we’re no further forward with our solar panel goals than we were when we first moved in, but that’s fine with the amount of surprise costs we have uncovered through the rest of the renovation!
The rest of our plans are underway to make the house more efficient and future-proofed, so although we’re not looking at any short-term solution at the moment, we’re still holding out hope that we will be able to power our home without the use of fossil fuels one day.
I had also hoped to add a heat pump to my home, but sadly that wasn't a viable option so I was looking into alternatives instead.