Could Solar Help Pay for Your Asbestos Roof Upgrade?
Could commercial solar help offset the cost of a roof upgrade? Discover how roof replacement, overcladding and solar PV can work together to reduce energy costs and improve ROI.
For many UK businesses, replacing an ageing commercial roof is an unavoidable capital cost. This is particularly true for older factories, warehouses and industrial buildings where the existing roof may be approaching the end of its serviceable life or contain asbestos. The question is whether that investment can be combined with something that generates a financial return.
A commercial roof replacement or upgrade combined with solar PV can provide an opportunity to do exactly that. Rather than treating the roof and solar as two separate projects, the combined investment can be assessed against the building’s electricity demand, expected solar generation, energy savings and long-term return.
For businesses with large commercial, industrial or warehouse roofs, this can turn a necessary building investment into an opportunity to improve the building, reduce electricity costs and create a long-term energy asset.
Turning a Necessary Roof Upgrade into an Energy Investment
If a roof needs replacing, the cost of the roofing works is unlikely to disappear simply because solar is being considered.
The question is whether the new roof can provide the platform for a commercial rooftop solar PV system, and whether the electricity generated can produce sufficient savings to improve the overall economics of the investment.
This is where the financial assessment becomes important.
The roof upgrade has a defined capital cost. The solar installation also has a capital cost, but unlike the roof itself, the solar system can generate electricity and produce a financial return over its operating life.
The combined assessment can therefore consider:
- Roof replacement or overcladding cost
- Solar PV capital cost
- Annual solar generation
- Electricity consumption
- Solar self-consumption
- Exported electricity
- Electricity price
- Annual energy savings
- Operations and maintenance
- Payback period
- Return on Investment (ROI)
- Net Present Value (NPV)
- Internal Rate of Return (IRR)
This gives the business a much clearer picture of the whole-life economics of the roof and solar investment.
What If You Have an Asbestos Roof?
Asbestos-containing roofs remain common across older commercial and industrial properties, particularly factories, warehouses and manufacturing facilities.
Where an existing asbestos roof requires attention, asbestos roof replacement or overcladding may need to be considered. The appropriate approach depends on the condition of the roof, the asbestos-containing materials, the structure and the requirements of the proposed roofing system.
For some buildings, an overclad system may provide an alternative to complete roof removal, subject to the appropriate specialist assessment.
This can also create an opportunity to consider solar panels on an upgraded commercial roof at the same time.
The important point is that solar should not be treated as a way of avoiding the necessary assessment of an asbestos roof. The roof structure, existing materials and proposed solar loading all need to be properly assessed before the design is developed.
Where a new roof or overclad is being installed, it makes sense to consider the solar system during the roofing design rather than returning several years later to install it.
How Can Solar Help Pay for the Roof?
The financial principle is straightforward.
The business invests in the roof upgrade and solar PV system. The solar system then generates electricity which can be consumed by the business, reducing the amount of electricity purchased from the grid.
Those electricity savings provide the return from the solar investment.
For example, consider a manufacturing business with a large roof and substantial daytime electricity consumption. If the solar system generates a significant proportion of its electricity during the company’s operating hours, a high level of self-consumption may be achievable.
That can make the electricity generated by the system particularly valuable because it is displacing electricity that the business would otherwise have purchased.
The resulting savings can contribute towards the combined capital investment in the roof and solar system.
It is important, however, not to assume that solar will simply “pay for the roof”. The financial outcome depends on the cost of the roofing works, solar system size, electricity consumption, tariff, generation, self-consumption and financing arrangements.
A proper financial model is needed to establish the actual return.
Why Combine the Projects?
There are several practical reasons for considering a commercial roof upgrade and solar installation together.
Avoid doing the work twice:
- Installing solar on a roof that is approaching the end of its useful life can create an obvious problem. The solar system may need to be removed or worked around when the roof eventually requires replacement.
- Coordinating the two projects from the beginning can avoid this issue.
Design the roof around the solar system:
- The proposed solar array can be considered when assessing structural requirements, access, loading, cable routes and other design considerations.
Create an energy-generating asset
- The roof is no longer simply providing weather protection for the building. Once solar PV is installed, it becomes part of the site’s energy infrastructure.
Improve long-term energy costs
- The solar system can reduce the business’s reliance on grid electricity and provide greater visibility over a proportion of future energy costs.
Support ESG objectives
- For manufacturers, logistics businesses and other commercial organisations, reducing operational carbon can also support wider ESG and supply-chain requirements.
Is Your Commercial Roof Suitable for Solar?
Before proceeding with commercial rooftop solar, the roof needs to be assessed technically.
Important considerations include:
- Existing roof construction
- Roof condition
- Remaining service life
- Structural capacity
- Solar loading
- Wind loading
- Roof orientation
- Shading
- Available roof area
- Existing plant and equipment
- Access and maintenance
- Cable routes
- Electrical connection
- Future building requirements
For older buildings, the structural assessment can be particularly important.
A large solar array introduces additional dead loads as well as wind-related loading. The proposed mounting system and its interaction with the roof need to be understood as part of the engineering design.
For an asbestos-containing roof, there are additional health, safety and construction considerations which need to be addressed by suitably competent specialists.
What About the Electricity Connection?
The financial case for commercial solar is closely linked to what happens to the electricity generated.
Where the building has substantial electricity demand, a significant proportion of generation may potentially be consumed on-site.
If there is more generation than the business can use at certain times, the project may need to consider export arrangements and the available grid connection.
For larger commercial solar installations, the Distribution Network Operator (DNO) requirements can also influence the system size, connection arrangements and project cost.
This is particularly relevant where a business is considering a large roof-mounted system alongside other energy technologies such as battery storage or EV charging.
The electrical assessment should therefore be carried out alongside the roof and structural assessment.
How Much Could Your Business Save?
There isn’t a standard answer.
Two buildings with identical roof areas could have very different financial returns because their electricity consumption and operating patterns are different.
The financial model should consider factors including:
- Roof upgrade cost
- Solar PV capital cost
- System size
- Annual generation
- Electricity tariff
- Annual electricity consumption
- Operating hours
- Self-consumption
- Export
- Financing cost
- Maintenance
- Electricity price assumptions
- Solar degradation
- Project lifespan
The output can then be assessed using measures such as commercial solar payback, ROI, NPV and IRR.
This is much more useful than simply asking how much a solar installation costs.
The real question is: What will the combined roof and solar investment cost, what will it save, and what return will it generate over its operating life?
An Example of the Approach
Imagine an industrial building where the existing roof requires replacement.
Rather than developing the roofing project in isolation, the business could assess:
Existing roof
→ Condition and remaining life assessed
Roof upgrade
→ Replacement or overclad designed around future requirements
Solar PV
→ System sized around electricity demand and available roof area
Electrical infrastructure
→ Connection and capacity assessed
Financial model
→ Roof CAPEX + solar CAPEX compared against energy savings and future value
Investment decision
→ Business can assess the combined project rather than considering the roof simply as a maintenance cost.
The outcome will be different for every building, but this approach gives the decision-maker the information needed to make a properly informed capital investment decision.
Energy Gain – Client Example:
The image below shows how this approach was applied on a project for a large manufacturing client in Stoke-on-Trent
The existing asbestos-containing roof was upgraded, with the new roof then providing the platform for a commercial solar PV installation.
The project demonstrates how a necessary roof investment can be considered alongside solar from the outset, helping the business assess the combined technical and financial opportunity rather than treating the two projects separately.
Energy Gain's Approach
Energy Gain can assess the roof, electricity demand and solar opportunity together, rather than treating the roofing and energy projects as completely separate exercises.
Our role is to help establish whether the proposed roof upgrade provides an appropriate platform for commercial solar and whether the combined investment makes technical and financial sense.
That can include reviewing available roof information, electricity consumption, proposed roof works, solar generation, self-consumption and the indicative financial return.
Where appropriate, the next stage can then move into detailed structural, electrical and engineering design.
Don't Just Replace the Roof, Consider What It Could Generate Electricity
If your business is facing the cost of an ageing or asbestos-containing roof, it is worth considering whether commercial solar PV could form part of the investment.
A new roof may be necessary. Solar may provide the opportunity to generate electricity and recover part of the wider investment through long-term energy savings.
The key is to assess both together.
Could your commercial roof upgrade become an energy investment?
→ Learn more through the Commercial Rooftop Solar Academy
→ Calculate your potential commercial solar savings
→ Or request a Free Detailed Desktop Feasibility Study
Energy Gain can help assess the technical feasibility and financial potential of combining commercial roof replacement, roof upgrades and solar PV into one coordinated investment.
