Automotive Parts Store Partial Industrial Roof Replacement with an Existing Solar PV Array
Queen Street East & Highway #410
Elite Roofing previously recovered the roof of this industrial building in July 2004. Given a typical 20-year industrial roof life span, we anticipated needing to do a partial or complete roof replacement around 2024. In 2012-13, nearly ten years after the recovery (which left behind the dry, solid fiberboard insulation) the landlord got approval to install a Solar PV [PhotoVoltaic] system over top of the rooftop space, through a 20-year contract with the Ontario Power Authority.
In late 2022, the client called us about replacing approximately 25% of their roof due to the extent of reoccurring leaks and the related expense for the roof repairs plus the extra costs of removing and reinstalling solar panels, racking, and electrical wiring at the various repair locations.
Deciding on the timing for an industrial roof replacement with a solar PV array
Before the client rented out the rooftop for solar, we discussed the difficult decision they would need to make. The first option was to replace the roof shortly before the middle of its life cycle, allowing them to avoid the extra future cost burden of removal and reinstallation of the solar PV system, craning, and all related electrical wiring connections, plus the loss in rental revenue while the system would be offline. The second option was to defer replacing the roof until the end of its life cycle, when the solar PV was already on the rooftop, with another +/-10 years left on the contract.
Each option had its pros and cons. Here are the key points of the two options:
Option 1: End-of-life industrial roof replacement with existing rooftop solar PV system
Deferring the roof replacement with solar PV already installed on the roof would incur additional costs and significant hassle. Why? Before replacement can begin, the solar company would need to perform the costly work of removing and storing the solar panels, racking, and electrical wiring–and then reinstalling these items after project completion. In addition, late-stage roofs often need more frequent or significant repairs, some of which may also require the same process for the affected section of the roof. The same may be true for other capital projects such as HVAC equipment that is roof mounted. The landlord would also lose out on the income generated from the solar PV system while it is offline.
Option 2: Mid-life industrial roof replacement before solar PV installation
By replacing the roof before installing the solar PV array, the landlord would only pay for the roofing work. They would not incur the extra costs to remove, store, and reinstall Solar PV panels and racking, reconnect the electric lines, and repair the vulnerable late-stage roof. By not deferring the roof replacement , the client would also synchronize the timing of the roof’s life cycle with the length of the solar contract for easier decision-making later on.
The 2013 decision to install or defer the solar PV
Based on numerous factors in 2012-13, the client decided on Option 1 above–to defer the roof replacement and move ahead with installing the solar PV array.
The industrial roof replacement process
Back to the present, the roof is now at the end of its life cycle and only midway through the solar contract. It’s time to replace it, requiring the removal and reinstallation of the solar panels, along with the related electrical work. The additional weight and accelerated wear and tear from weather and movement of the solar assets and the increase in roof traffic led to an earlier than expected demise of the roof membrane.
The scope of work for the current project includes:
- Scheduling the solar company to remove the solar panels and racking, with the related electrical work
- Complete tear-off and roof replacement, including base insulation and roofing accessories
- Scheduling the solar company to reinstall the solar panels and racking, with the related electrical work
In fall 2022, the tenant noticed several leaks in the unit. With the roof reaching the end of its expected life span, the landlord hired us to replace it. We agreed to replace approximately 25 percent of the roof this year, beginning in April 2023. As expected, dealing with the solar PV panels led to several challenges:
Small area for ground storage
The building site did not have enough “available” ground area to store the solar PV equipment. Further, the tenant’s business activities required that its’ products be stored outdoors, further limiting ground space. By far, the biggest challenge was where to safely store the solar panels and racking while we were working on the roof.
Other considerations included:
In looking at the roof’s structural capacity, a previous structural engineering report limited the additional live load that could be placed on the roof. Therefore, it was not possible to temporarily store the disconnected existing solar PV array panels and racking on the roof during the replacement.
Coordination with solar company
Planning required scheduling the removal, storage, and reinstallation of the solar PV with RESco Energy, the solar company.
Solar panel downtime
We wanted to minimize solar panel downtime and maximize energy production during the restoration.
Together with the client and the solar contractor, we considered all relevant factors to create a plan that addressed our main challenges. This plan included:
We scheduled the project for April completion to minimize the energy loss from the solar array and to reduce work stoppages related to winter storms.
The tenants created space for our staging area at the base of the building without hindering their operations.
Maximum ground storage
First, the client arranged for the solar company to remove 50 percent of the panels, storing them on 53-foot tractor flatbeds to be moved and stored off-site. After completing work on the first section of the roof, the solar company relocated the remaining panels onto the completed area, exposing the other section of the roof for replacement. Once we completed the roof replacement, the solar company reinstalled the stored panels. In addition to gaining ground space, the current plan eliminated any concerns about the added live load to the roof.
Smooth work process
The process created enough storage room for the panels, our equipment, and disposal bins. The added space also enabled us to more effectively schedule the arrival of materials for continued site access and a smooth work process.
- Building Height: +/- 24’
- Total roof area: approximately 150,000 sq ft
- Roof replacement area: approximately 35,000 sq ft
- Vapour retardant: reinforced kraft paper
- Insulation: 1.5” Polyisocyanurate and 0.5” Perlite cover board
- Membrane Type: 4-ply built-up roofing with roofing asphalt and a flood coat of hot roofing asphalt
- Ballast: 3/8” pea gravel
- Flashings: 2-ply SBS Modified Bitumen
- Metal copings: 26 Gauge pre-painted Series 8000 metal
The project is still in progress and going according to plan, with all milestones met as originally planned. Also important, the tenant’s day-to-day operations have not been interrupted. The main takeaway from this project is that while replacing a rooftop with solar arrays can be challenging, proper planning and careful coordination with the solar company are critical to success. If your Toronto-area industrial building has a solar PV array and needs roof repair or replacement, you can count on Elite Roofing’s experience and craftsmanship. Contact us today.
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