The good news is that professional installers can safely fit solar panels to most suitable roofs without causing any damage. The important factors to consider include your roof’s current condition, the type of mounting system needed for your solar panels, and the workmanship.
Several problems can occur from poor quality installations, which is why it’s important to understand what a professional installer should ideally do before starting any work. A professional, certified installation actually protects the roof from weather, whereas ‘cowboy’ installations cause the countless horror stories you may have already read about online.
Our expert guide to solar panel installation and your roof goes into greater detail about the main considerations, covering everything from roof suitability to the practicalities of fitting the panels.
The short answer: do solar panels cause leaks or structural damage?
No. If your system is properly designed and installed by professionals, then solar panels won’t damage your roof. However, fitting them involves work on your roof, and mistakes can potentially cause tiles to crack, leaky roofs, or issues with the actual structure of the roof.
In fact, the panels act as a protective shield for the tiles directly beneath them, defending them against rain, UV rays, and snow. The likelihood of your roof being damaged is exponentially increased with shoddy workmanship, which happens when using tradespeople who aren’t properly qualified to carry out the work, or if your roof wasn’t structurally sound before work began.
Systems that are installed correctly will use suitable mounting hardware, appropriate weatherproofing, and secure fixings. Other key factors that will also be taken into account include the forces created by strong winds and the weight of the panels themselves.
Solar panels act as a kind of shield for the roof beneath which they are mounted, which gives them a certain amount of protection from rain, snow, hail, and direct sunlight. However, your roof won’t be made waterproof by the solar panels, and water still needs to be able to drain beneath and around them.
Before you go ahead and have solar panels installed, your roof’s current condition is considered equally as important as the work you have done on it. If you find that some of the tiles on your roof are already damaged before work begins, if the roof is approaching the end of its useful life, or if you spot that the timber is already in a state of deterioration, it’s important that you get these issues looked at and fixed before fitting any panels.
Although much older roofs can still be suitable for solar projects, they will always need to be assessed first. Getting them checked out by professionals will let you know if anything needs fixing, unlike unqualified tradespeople, who may start the work regardless of your roof’s poor condition.
The biggest risks of a poor solar installation
More often than not, poor workmanship, failure to properly assess the roof before installing solar panels, and unsuitable fixings are the most common problems associated with damaged roofs.
Cracked or broken tiles
If tiles are subject to excessive pressure or they are handled carelessly, they can crack. Slate can also become fragile, especially on roofs that are much older.
When fitting the mounting equipment and working on your roof, installers must take extra care, and if they end up cracking one or more of the tiles while the work is being carried out, they should be replaced as soon as possible and not left broken underneath the solar panels.
Although broken tiles might not instantly cause a leak, they will eventually allow water to seep through the underlay or reach the timber. This is why it is important to deal with damaged tiles straight away because fitted panels make it more difficult to access the area beneath.
Poor flashing and water ingress
To ensure the roof remains weather-resistant, roof fixings must always be installed correctly. For example, poorly mounted fittings or openings that aren’t properly weatherproofed can make it easier for water to find a way in through the roof.
You will find that mounting brackets are designed to sit beneath the tiles and attach to the rafters or other specified structural members, especially on traditional tiled roofs. First, the tile is lifted, which enables the bracket to pass through before being repositioned around the fitting.
Some tile adjustments or specialist flashing may be required, though. It all depends on the roof covering and mounting system.
The main emphasis here is that brackets shouldn’t simply be screwed through the roof tile’s exposed face and left to rely on water being kept out by a sealant.
Furthermore, different fixing methods are required for different roofs, such as clay tiles, slate roofs, and concrete tiles, plus various other coverings. They all have their own installation considerations.
Each roof in question must have its own suitable system, and if the roof is penetrated at any point, it must be properly detailed and weatherproofed.
Wind uplift and loose mounting rails
Solar panels are always exposed to the weather, which includes strong winds. Therefore, the array and its mounting system must be designed to withstand all conditions, and strict guidelines and installation standards for wind uplift and weatherproofing must always be adhered to by certified installers.
If the rails are not secured to suitable structural members, or the fixings are incorrectly selected or installed, wind can place excessive strain on the mounting system, especially if the rails aren’t properly secured. This can lead to mounting components or panels becoming loose over time.
The Microgeneration Certification Scheme (MCS) publishes installation standards for solar PV systems. Their standards cover various aspects, such as installation practices, appropriate materials, the safe design of the system, and suitability of the building.
When installing solar panels, instead of using the same fixings on every property, professionals will carefully consider the roof structure, the mounting products and the local conditions.
Pre-installation: how we check your roof is safe
Before carrying out any agreed work on your roof, installers must first establish whether the proposed system will be suitable for the roof. This is particularly important on roofs with visible defects, older properties, and buildings with unusual construction.
A proper assessment should consider several factors, such as the age and current condition of your roof.
During the inspection, installers must check the roof covering for loose, cracked or missing tiles, signs of water leakage, damaged slate, and other possible issues. The condition of the underlay and any visible signs of deterioration also need to be taken into consideration by the installer.
You don’t need a brand-new roof to support your solar array. However, if the roof they are going to be installed in is likely to need replacing soon, or major repairs, it can save you a lot of money to get this work done before, as opposed to having to remove them after they have been installed and then reinstall at some point in the not too distant future.
Roof structure and weight-bearing capacity must also be considered. The mounting equipment and solar panels themselves can add a great deal of weight to your roof, so it’s also important for the installer to consider the relevant wide loads and whether the proposed system can even be supported by the structure.
This may involve assessing various structural elements, such as trusses and rafters. The best course of action all depends on the property. If it isn’t clear whether the roof will be able to hold the solar panels, then you may need further checks to be carried out by a suitably qualified structural professional.
This is also particularly relevant for roofs that are currently showing signs of sagging or movement, as well as properties that may have had work done, and much older buildings.
Choosing the correct mounting hardware
Your solar panel’s mounting system also needs to be suitable for the structural arrangement and roof covering. On your average tiled roof, this will likely involve roof hooks secured to the rafters, with the tiles being carefully repositioned around them.
The panels are then supported by mounting rails and will distribute the loads via the designed fixing points. The mounting system manufacturer’s instructions and the installation requirements must be followed precisely.
To understand the main stages of a typical domestic installation, you can read more about how an install works in our expert guide.
Checking the roof as part of the wider installation plan
The condition of your roof is just one design element to consider. Other important parts of the design include things like accessibility to the roof, cable routes, shading, and any other features that could potentially affect the work.
Don’t forget that inspecting the roof to find potential issues before work begins is a critical part of planning your solar panel installation and your roof project.
The Energy Saving Trust recommends having the roof assessed as part of the installation process and using an MCS-certified installer. Their guide to installing solar panels covers several topics that homeowners will likely encounter during the entire process in much greater detail.
Why do some people have to remove their solar panels?
Well-designed and properly installed solar panels should ideally operate for several decades, so removing a working system is not usually the first choice. One of the reasons why some homeowners end up taking panels down is simply to repair or replace the roof underneath them.
For example, a much older roof that was already nearing the end of its usable life when the panels were installed may eventually need new tiles. New underlay may also be needed, or you might need structural repairs carried out.
To ensure that your roofers can carry out their work, you may have to temporarily remove the panels and mounting equipment, and then refit them afterwards, which isn’t ideal because it significantly increases the total cost of the work you have done on your roof. Again, this is why you should always assess the roof’s remaining lifespan before having any solar panel work done.
If your roof is showing signs of significant deterioration, leaking or sagging, arrange for it to be inspected before committing to solar panels. It’s also worth bearing in mind that the age of your roof alone won’t necessarily determine whether having solar panels is suitable or not. However, if your roof is, say, around 30 to 40 years old or more, then it may deserve closer inspection if it is proving difficult to ascertain its actual condition.
The most practical and financially viable option is to complete any work that needs doing on your roof before having solar panels installed.
It is also highlighted on the National Federation of Roofing Contractors (NFRC) website about the risks of installing solar PV on roofs nearing the end of their service life. Its guidance on solar PV and roofs explains why solar PV must be integrated correctly without compromising roof warranties and why the condition of the roof must be assessed prior to any work being carried out.
What happens to my existing roof warranty?
Remember to check the terms before arranging solar installation if your roof is new or still covered by a builder’s or manufacturer’s warranty because some warranties have conditions relating to penetrations, alterations, additional loads or work carried out by third parties. Your cover for certain problems could be affected if you go ahead with the work without following these conditions.
Before proceeding:
- Inspect your warranty documents. Pay close attention to conditions including third-party work, additional equipment, and alterations to the roof.
- Get in touch with your roofing contractor or builder. Find out if the installation for your proposed mounting system is compatible with your current roof and warranty.
- Use the correct mounting products. When installed correctly, approved hooks, fixings and flashing designed for the roof covering can help maintain weather resistance.
- Don’t chuck the paperwork. When any work is carried out, make sure you keep hold of the warranties and any other important documents you received for the installation and mounting system.
Using appropriate mounting hardware does not automatically preserve every roof warranty. The answer depends on the warranty terms and the proposed installation, so it is best to confirm this before work starts.
If the work is likely to affect waterproofing or your roof’s long-term performance, the NFRC recommends that roofing expertise naturally forms part of the solar installation process. Their guidance on solar panel installation discusses why competent roofing work matters.
One of the only major downsides to solar panel technology is that they are only capable of generating electricity in the daytime, more specifically, during the brighter parts of the day, but your household sometimes uses more electricity in the evening when solar generation is no longer possible.
However, a battery can easily counter this by storing some of the electricity generated during the day for later use, but they cost extra and aren’t necessarily included in every grant-funded installation. Someone who pays privately can choose whether adding a battery makes financial sense for their household.
Solar panels are designed to last for decades, and you tend to find that most modern panels come with long performance warranties, typically up to around 25 to 30 years, but they don’t simply stop working when that period ends. Instead, their electricity output gradually decreases over time.
In contrast, inverters usually have a shorter lifespan than the panels and may need replacing during the life of the system, quite often when they are around 12 years old.
You may or may not have seen news reports or articles about solar panels being removed by homeowners, and some of you may have automatically assumed that people are doing this because they aren’t working properly.
While this could be the case, it’s generally not the case. Sometimes, panels are temporarily removed because the roof that they are installed on may need minor repairs or to be replaced entirely with a new roof. After the roof has been fixed, they can potentially be reinstalled.
Some homeowners have chosen to end those older arrangements, such as the Rent-A-Roof arrangement, or they are simply replacing older systems.
Removing panels doesn’t mean that solar technology itself has stopped being useful. The age of the system, ownership arrangements and condition of the roof all need to be considered.
Conclusion and next steps
Solar panels aren’t likely to cause any damage to your roof. Provided the roof is suitable, has the correct mounting system and is carefully installed, they should keep generating decades of electricity without compromising the structural integrity of the roof or how weather-resistant it is.
The underlying message is to ensure that the roof itself isn’t overlooked. Things like poor flashing, inadequate fixings, an older roof, and broken tiles can potentially cause multiple issues, especially if they aren’t dealt with before you have solar panels installed.
A proper assessment will afford you a much clearer picture that will tell you if any repairs are needed, whether solar panels can even be installed in your roof, and which mounting arrangement will be the most appropriate for your property.
If you are considering going ahead with your solar project, Spartek can help go through your options with you today and carefully plan an installation around your home. Find out more about solar panels for your home and take the next step towards designing a system that will be best for your property.
Worried that solar panels could cause roof leaks or damage your tiles? Find out how professional installation, suitable mounting brackets and pre-installation roof checks can help give your home the best protection.
