two roof workers installing solar panels on red clay tile roof

Solar panels are now an option for most homes. According to the Solar Energy Industries Association, more than 2 million PV installs are in the USA. The rapid growth is due to the many benefits these units bring.

PV and solar panels help reduce your energy bills and combat the emission of greenhouse gases. What’s more, their prices have dropped by about 70%.

For homeowners, roof-mounted solar panels present a great way of harnessing the sun’s energy. But before installing panels, your roof must meet specific requirements. Below are essential solar panel roof requirements.

Roofing Materials Ideal for Solar Panel Installation

Not all roofing shingles are ideal for solar panels. Roofing materials made from slate tiles, clay, and wood aren’t suitable for solar panel installation. These materials are fragile, meaning they pose a lot of challenges to contractors mounting them.

Some jurisdictions won’t permit you to install solar on wood shake roofs. Wood is a potential fire hazard and presents safety issues.

That said, many common roofing materials can accommodate solar panels. Some of these materials include:

  • Asphalt shingles
  • Tile
  • Metal

Standing metal roofs are the most suitable for mounting solar. These roofs are durable, provide a secure base, and you can make installations without drilling them.

Recommended Roof Sizing for Solar Panels

The average residential PV module is about 3×5 feet, meaning each panel will occupy around 15 square feet.

Most American homes require a 5kW solar power system to meet their energy needs. That means you need approximately 20 panels (250 W) on your roof. In addition, your roof must have at least 300 square feet of free space to accommodate these panels.

A larger family with more energy needs will require more panels, which translates to more roof space. Keep in mind however that if you don’t need to meet “all” of your energy needs you can install fewer panels.

Measuring your roof size isn’t as straightforward as it looks. You’ll need to factor in features like chimneys and dormers. It’s advisable to enlist roofing contractors to measure your roof and calculate the required number of panels.

Never purchase PV modules without determining the size of your roof.

The Pitch of Your Roof Can Affect Panel Installation

Roof pitch is among the solar panel roof requirements. You get this pitch by dividing the rise by the roof span.

In most cases, the ideal roof incline for solar installation is 30 degrees. In construction terms, this is a 7-pitch roof. The roof rises seven inches over a horizontal run of 12 inches.

A steeper angle (greater than 45 degrees) will slightly affect the energy production of your panel. Contractors might also face difficulties when installing PV modules to vertiginous roofs.

A flat roof poses many issues for solar panels. First, panels on flat roofs may be less efficient since they aren’t tilted towards the sun. Second, these panels tend to attract dirt and lose productivity. Lastly, water may pool around your solar unit and damage it.

Despite these challenges, you can use several mounting techniques to install PV systems on flat roofs. You may incur extra costs when installing tilt-up racking systems.

How Old Your Roof Is

It isn’t a good idea to mount solar panels on old roofs. You will end up paying additional funds to your roofing contractor to remove panels before installing a new roof.

Besides, roofs undergo rapid deterioration as they age. So your old roof risks crumbling down if you add the additional solar panel weight.

Most roofs survive for about 20 years. Notable signs of aging include:

  • Curling shingles
  • Missing shingles
  • Rotting roof
  • Excessive growth on the roof
  • Streaks and decolorization

Never install PV panels on roofs that are more than 15 years old.

Panels have a 25–30-year lifespan and will likely outlive any older roof. Installing a new roof before putting solar panels on your roof is ideal.

damaged and missing shingles on roof

Your Roof Required Condition for Panels

Your roof must be in good condition to support PV panels. The average weight of most residential solar panels is around 40 pounds.

These panels plus mounting hardware add about 3 to 4 pounds per square foot of load to your roof. This weight isn’t much but is capable of destabilizing roofs that are in poor condition.

PV modules are also flat, making them susceptible to strong winds. For example, the wind might blow off your panel if you anchor it to a deteriorated or rotted roof.

Always inspect your roof for potential damages before you mount solar panels. Vital aspects you should check include:

  • Shingles
  • Vents
  • Underlayment
  • Flashing

Watch out for damaged trusses, leaks, mildew, streaks, and cracked shingles.

Remember, a damaged roof lacks the structural integrity to support any additional load. Consider hiring a roofing expert to assess your roof condition.

Shade Around the Roof Matters

Modern modules require about 6 hours in sunlight to recharge. Any shade around your roof will significantly hamper the production of your PV system.

Shade on your roof can be from nearby buildings, trees, dormers, chimneys, or other obstructions.

If you have trees around your roof, you can trim or cut them. However, other sources of shade might be challenging to eliminate. Enquire from a solar panel contractor whether a shade near your roof will affect your solar panel.

Your Roof’s Orientation

The orientation of your PV panel directly impacts its production capacity. The ideal exposure primarily depends on where you reside. In general, south-facing panels (180 degrees true orientation) work more effectively.

If you live in the Northern hemisphere (USA, Canada, Mexico, West Indies), you will significantly benefit from south-facing panels. Your panel will effectively harvest solar energy as the sun passes through the southern sky all year.

Your panel’s productivity will start decreasing if you change the orientation. PV modules that face southeast or southwest function properly, but those facing other directions might work inefficiently.

Below is the output loss for each direction.

  • North – 30%
  • West/East – 15%
  • Southwest/Southeast – 8%

Don’t fret if your roof face doesn’t have southerly exposure. You can still harness solar energy by mounting your panel on a rack. The rack will enable you to adjust your solar to the proper orientation.

black solar panels on gray shingle roof

Can Firefighters Easily Access Your Roof?

In case of a fire or smoke emergency in your home, firefighters will ascend to your roof ridge and cut a hole. The hole serves as an exit point for the smoke and gases.

There have been cases where firefighters were unable to carry out their tasks due to rooftop solar panels. That’s why it’s advisable to provide a path for firefighters when mounting solar panels.

You should provide at least two paths, each starting from a lower roof edge to the ridge. The width of the path depends on the available space, but ensure it’s helpful to firefighters.

Do You Need Permits to Install Solar Panels?

Yes, all states require you to get a permit before mounting PV panels on your roof. You have to meet safety and solar panel roof requirements before undertaking such a project.

Some of the permits you should have include:

  • An electrical permit
  • A building/structural permit
  • A dedicated photovoltaic permit

The exact permit requirements vary from one locality to the other. The size and type of solar unit will also influence permit requirements.

firefighters on shingle roof

An inspection is necessary before you mount your PV system. Among these criteria, you must adhere to the electrical codes. Your local electrical inspector will determine whether you adhere to these codes.

Most local governments conduct a post-inspection process to ensure your installed PV unit abides by building and safety regulations. Your utility company may also participate in this inspection and later replace your meter with a net meter.

You will receive Permission to Operate (PTO) once the utility company reviews your system and connects it to the grid.

You don’t have to undertake all these time-consuming processes. Instead, simplify your work by hiring a reputable solar panel installer. The solar panel company you enlist will handle all the requirements on your behalf.

Does Installing Solar Panels Void Your Roof Warranty?

If you mount your PV panel correctly, it won’t void your roof warranty. Solar panels rest on rack systems, which aren’t detrimental to your roof. A well-installed system will even protect your roof from the elements.

Issues occur when mounting systems penetrate your roof or violate the manufacturer’s specifications. Roof damages might occur due to:

  • Negligence by the solar panel installer
  • Equipment damage when installing PV panels
  • Poor installation of racks, fasteners, or flashings
  • Poor quality rack systems

There’s always the risk of roof damage when you mount panels on your home. That’s why reputable solar installation companies offer workmanship warranties. This warranty will cover you for almost ten years against damages caused by PV installation.

Also, check whether your roof coverage protects your roof from installation damages.

It’s necessary to consult with your roofer on the implications of solar panels on a roof warranty. Your roofer is likely to be well-versed in the types of contracts that may turn void during solar installation.

It’s vital to hire qualified PV panel installers. Ask the installing company about warranty issues when contractors dent your roof.

Installing rooftop solar panels is a significant investment in your home. But before undertaking such a project, ensure you adhere to solar panel roof requirements. The above guide should help you understand whether your roof can accommodate solar panels.

If you find yourself wanting to get a new roof (one that works well with solar) to prepare for installing solar panels, reach out to Secured Roofing and Restoration! We can get you a roof inspection and help you in the following steps towards going solar.

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