You should consider many factors to determine whether your roof is suitable for solar panels. It is crucial to consider the size of the roof, direction, angle, types of tiles, loft space, and the amount of shading on it. When installing the solar panel, you should seek the services of a qualified installer. The installer will evaluate the specific characteristics of your roof, identify any problems, and potentially resolve them. The expert will also inform you if a solar panel system is financially unviable or unsafe on your roof.
Typically, these are the factors you should consider when determining if your roof is suitable for solar panels:
The Direction Your Roof Is Facing
A south-facing roof is ideal for solar panel installation because it receives sunlight throughout the day. East or west-facing roofs are also good and can generate significant energy, but their output is not as high as that of a south-facing roof. A north-facing roof does not have the best exposure to sunlight. Fortunately, advancements in technology have made it possible for most homeowners to benefit from north-facing solar panel systems, especially if it is a northeast- or northwest-facing roof. Even in southern regions of the U.S., north-facing roofs generally receive less sunlight, which can reduce solar panel efficiency.
The Roofing Material
It can be challenging to install solar panels on some roof tiles. A solar expert can still install the solar panels, but it can take a lot of time, and the installation would be more costly. The best tiles are those with consistent size, shape, and clay. Other roofs have tiles made of materials which differ in weight, depth, and size. Some tiles are often heavy and larger than clay and concrete tiles, overlapping each other, making them hard to lift. As a result, the solar expert will take a lot of time and use extra mounting equipment. This can be expensive, but your roof will not suffer any damage.
Given the advanced roof-racking methods in use today, solar panels can be installed on almost all types of modern roofing materials. Solar panel installation can be done on any of the following roofs:
- Decorative shingle
- Architectural shingle
- Composite shingle
- Standing seam metal
- Corrugated metal
- Rolled asphalt
- Flat time, W-tile, S-tile, and others
Solar panel installation can be problematic on the following roof types, even though some experts can still install them:
- Clay tile
- Slate tile
- Shake tile
- Metal slate
- Metal tile
- Corrugated asphalt panels
- Metal with asphalt coating
- Fiberglass panels
- Rubber flat roof materials
Most roofing materials can withstand the solar panel installation process, except the highly flammable roofing materials like thatch roofing and wood shingles.
Roof Space And Obstructions
Any inconsistencies or obstructions on your roof could limit the buildable size of the solar array. The common obstructions on roofs include window dormers, HVAC vents, and chimneys. Most municipalities also have restrictions that restrict the installation of solar panels within certain distances from the building’s edge. The ideal roof shape for solar panels is a rectangular roof. The roof should also not have many obstructions and pitches.
To meet the average residential electricity needs in the U.S., the roof space needed for solar panels is between 300 and 450 square feet. An average solar panel is around 17.5 square feet. Most residential solar energy systems have between 18 and 24 panels.
Flat Roofs Versus Pitched Roofs
You could wonder whether your pitched roof is too steep for solar panel installation. The rule of thumb is that the ideal pitch should be between 30 and 45 degrees. While a pitched roof is perfect, any surface that receives sufficient sunlight is suitable for solar panel installation.
Extra equipment is required when installing solar panels on a flat roof. The additional equipment can increase the installation costs. However, you can use a concept similar to when installing solar panels on open fields. You can use mounting systems on your flat roof to raise your solar panels to an angle that receives adequate sunlight.
The Age Of Your Roof
Your roof might not be ideal for solar panels if it is old and reaching its later stages in life. If your roof is worn out due to wear and tear from years of weather, you should replace the roofing material before installing the solar panels. This way, you will not have to remove the solar panels to repair or replace the roof. If your roof is over ten years old, a professional inspection should be performed before installing solar panels. This will ensure the roof is structurally sound and has a reasonable lifespan.
Whether Your Roof Can Support The Weight Of Solar Panels
You might establish that your roof is not suitable to support the extra weight of a solar panel system. This could be the case if your roof does not have sufficient rafter support. However, it might be challenging to identify this structural weakness unless you have an on-site engineering survey. You must demonstrate adequate roof support to meet the roof requirements for solar panel installation. Before installing solar panels, check with your local building & zoning authorities. The local building codes must approve solar panel installation.
If your roof has inadequate support, various workarounds can be performed to accommodate the extra weight of solar panels. Consider talking to a solar installation expert for safety purposes and to ensure that your roof passes the safety inspection.
The Angle Of Your Roof
The ideal roof angle can vary depending on your location and the desired output of your solar energy system. Ideally, the angle for rooftop solar panels should be between 30 and 45 degrees. Many roofs are within this range, enabling the panels to capture sufficient sunlight. People with houses whose roofs have slightly lower or higher angles can also save a lot of money on electricity bills. On the other hand, flat roofs, like those on dormers, are more problematic.
A solar expert should not drill into a flat roof because it can cause leaking when it rains. Instead, the installer can consider ballasting your panels. Unfortunately, ballast is heavy, making the system significantly heavier. Solar panels installed on a flat roof can also cast shade on each other. You can avoid this by spacing the panels, but spacing can also reduce the number of panels you intend to install on your roof.
Shading On The Roof
Shading is a common obstacle for most prospective solar panel owners. The solar system will produce less electricity if it receives less sunlight. You should work out the period during which the trees cast shade over your roof each day if they are your main problem. It is good to consult a professional installer because he/she can assess this accurately while designing your system. A short period in the shade cannot be an issue, but if the trees are more obstructive, have them cut down or trimmed. On the other hand, it can be challenging to deal with buildings that cast shade on your roof.
You should consider the roof because objects like dormers, gable features, flue pipes, vent pipes, and chimneys can cause shading. A solar panel installation expert can use microinverters or optimizers to solve the problem if your rooftop experiences substantial shading. However, the new solar panels have built-in technology known as bypass diodes that deal with shading issues.
Aesthetic Considerations
You should also consider how the solar panel will appear on your roof and whether it will affect your home’s aesthetic standards. Your home’s aesthetics can affect your choice of solar panel. Aesthetic preferences are a significant factor, especially when dealing with an HOA. Solar panels come in different types and colors. You should choose one that complements your roof for the best aesthetic results.
Type Of Loft Insulation
Spray foam insulation is liquid plastic, which can be applied through a spray gun to ceilings, walls, and floors in your house to prevent cold and preserve heat inside. It is common to use this insulation to fill lofts in corners and areas that are hard to reach, which will be hard to cover with solid insulation materials like fiberglass. This insulation can also extend below your roof, between the rafters, which can prevent the solar installation technician from checking your roof. The solar panel installation expert might also find it challenging to determine the condition of your felt.
The Condition Of Your Roof Felt
Your roof felt should have a lining before you secure solar panels. An experienced solar panel expert cannot place solar panels on your roof otherwise. If you have no roof felt, the solar panel installation expert will also check to determine if your roof is damaged. A damaged roof can leak after installation, or the roof tiles can dislodge and destroy the solar panels.
The solar panel installation expert will feed your solar panels’ DC cable through a fold in the felt membrane of the roof and into the loft if you agree with them on an internal cable run. Sometimes, he/she will thread the cabling through the house to your battery and inverter’s location, whether in your garage, outside, or under the stairs.
An experienced solar expert will put the cables in trunking. A trunking is a plastic enclosure that keeps the wires protected and neat. The wires run through a room's corner or an airing cupboard. The installer can also place the battery and the inverter in the loft. However, this can only be done if the loft has a large hatch and sufficient space for an inverter. It can also be done if there is a gable end wall where the battery can be mounted. If your loft meets the above requirements, the solar panels installation expert can easily consolidate the cabling and connect it to the inverter.
The Space Beneath The Loft
If you have a loft space, installing solar panels on the rooftop is easier. The installation expert will check the space below the roof to examine its structure and establish where the rafters are. He/she will also check to determine if the felt is torn and the bolts are straight into the rafters.
You should have an eaves hatch if you have a loft conversion. An eaves hatch will give the installation technician a view of the structure, felt, and rafters. A diagram or blueprint of your roof will be enough if you do not have an eaves hatch. You will be forced to pay for an invasive survey if you do not have either. An invasive survey involves cutting into the ceiling of the loft.
The installation can be challenging if you have a vaulted loft ceiling covering the rafters. The solar panel technician will not be able to assess the structural safety of the roof and carry out post-installation checks. In this case, long-term and costly damages can occur without anyone noticing.
A solar technician cannot guarantee that the felt is intact, the rafters have not cracked from the impact, or the panels’ mounting structure is connected. Competent solar panel installation experts cannot install solar panels on houses with a vaulted loft ceiling.
What If Your Roof Will Not Work With Solar Panels?
You might find out that your roof is not suitable for solar panels. This could be due to shading, obstruction, or orientation. If a rooftop solar system will not work, you do not have to give up on solar energy. You can go for a ground-mounted solar system. This system would be ideal if you have sufficient ground space, preferably away from obstructions and shadow-casting trees.
Even if rooftop or ground-mounted panels cannot work, you can still benefit from solar energy. You can buy solar energy from the community solar array, depending on your location.
If you live in an HOA or historic district, the solar panel installer will advise you on how to go about seeking approval. The installer must ensure the solar panel installation complies with the historic requirements.
Find a Reliable Solar Panel Installer Near Me
Determining if your roof is suitable for solar panel installation is just one part of going solar. You should contact a professional solar panel installer to assess your condition and advise you accordingly. An installation expert will assess your roof’s suitability and give recommendations based on your unique circumstances and energy goals. Sun Solar Electric strives to change how the world is powered by making solar energy accessible. With decades of experience, we are the go-to solar panel installers in the Bay Area and Northern California. Contact us today at 707-658-2157 to speak to one of our installation experts.
