Installing Solar Panels On A Flat Roof
With such a growth in demand for renewable energy, installing solar panels on a flat roof has become a fairly straightforward process and should be easily accomplished by a professional team.
The first step will be to estimate your power potential. This means your installer will:
- Help you assess how many panels you can fit on your roof, given adequate spacing for perimeter or parapet walls, spacing the panels so they dont shade one another, and avoiding any pre-existing air conditioning units or other fittings that might get in the way of the panels or maintenance access. Hoymiles have worked to deliver optimized power generation for even the largest roof spaces.
- Assess the condition of your roof and make sure that if it will need replacing or upgrading that is either done in advance of installation or that temporary removal of your panels will be easy to accommodate.
With some stricter legislation surrounding flat roof solar panel installations for example, youll need planning permission if youre based in the UK its important that you work with expert installation engineers who can carry out the proper checks and make sure your roof will still comply with relevant building standards, particularly around water tightness and weather protection.
Your engineer will also design your panel array to suit your specific location, for example when it comes to mounting angle and alignment:
Choosing The Right Solution Solar On Flat Roofs Ballasted Attached & Hybrid
David Briggs and Jon Haeme | IronRidge
If youve installed solar on a steep pitched roof, working on a flat roof probably seems like a dream come true. Theres no hardware rolling down gutters, no fall protection lanyard tripping you, and you can use a wheeled cart to move equipment around the job site. Whats not to like?
And to sweeten the pot, designers of flat roof projects also have a lot more working space, so to speak. They can select from a variety of configuration and layout options to maximize performance, minimize material costs, or streamline construction.
Ironridges Flat Roof Attachment can be used with its BX ballasted system to provide additional support in high wind or seismic areas.
In particular, the options for structural design are incredibly broad. Designers can choose everything from using ballast weight for anchoring to building a superstructure above the roof for increased equipment clearance. Both of these options are simply unavailable on pitched roofs, where attaching directly to rafters, at fixed intervals, in a flush mounted configuration is practically the only viable approach.
Adding solar into this situation only adds to the complexities.
The IronRidge BX ballasted system offers the tightest inter-row spacing, fully maximizing power density.
The content & opinions in this article are the authors and do not necessarily represent the views of AltEnergyMag
How Do They Work
The solar panels that are used on a flat roof are exactly the same as the ones used on a pitched roof. You can technically lay the panels down on a flat roof just as you would on a pitched roof but this will restrict them from absorbing as much sun as possible, and might also lead to water damage.
Thats why you need to install a framing system, to tilt your panels towards the sun. This will help them self-clean in the rain, and avoid damage from pooling water.
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Is Solar Panel Installation Possible On A Flat Roof
You’ve been thinking about getting a solar system for your home. You’ve heard about all the ways it can save you energy, and it sounds like a great opportunity. There’s only one problem: you’ve always heard that solar panels need to be placed at an angle, to catch the sun’s rays. And your roof is completely flat. Are you still able to install solar panels on your home?
The short answer is YES…but there are choices and issues to be considered that aren’t necessary for solar panel installation on a pitched roof.
How To Find A Company To Install Solar Panels For Your Flat Roof
If you live in an area where many homes have flat roofs, its likely that your local installers will have experience working with these kinds of systems. However, you should always get multiple quotes from installers to ensure that youre working with a company that has the right expertise and background for your needs.
The best way to find multiple local solar installers is to register your property on the EnergySage Solar Marketplace. When you join, simply indicate the location of your property on Google Maps so installers will know that your property has a flat roof . To ensure that you get quotes from companies who will work on your property, you can also indicate that youre looking for a flat roof installation when you set up your preferences after joining.
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Other Considerations For Flat Roof Solar Installations
None of these factors mean that it isnt worth looking at a flat roof system: they simply mean that the process is more involved and it is more important than ever that the system is designed and installed by knowledgeable experts.
At Spirit we have undertaken planning applications for, and installed, a large number of flat roof systems on a variety of properties using different mounting systems and as such are able to advise on the best solution for any given property.
Attached Solar Racking Systems For Flat Roofs
The first type of solar panel rack that can be used on a flat roof is an attached racking system, similar to those used with sloped roofs. Theyâre called attached because they are fixed in place by fasteners, usually bolts or screws.
With this system, the racks are secured to the roof with mounts that are fastened to the roof deck. This means drilling through the roofing material and then attaching fasteners to the structural surface underneath, which is a layer of plywood or oriented-strand board that is called sheathing.
Once properly secured to the sheathing this way, the solar panels are very secure and wonât blow away even in the highest winds.
The main installation detail thatâs important is to ensure that the mounting points are made waterproof – after all, holes are drilled into the roof. If these holes arenât waterproofed properly, youâll have leaks and an expensive repair to deal with later on.
The example above is the IronRidge XR Tilt Mount. The highlighted area shows the footing, which is screwed into place on the roof. It also comes from the manufacturer with a waterproofing membrane. The manufacturer also recommends an additional sealant if the home is in a climate that experiences freezing.
This system also adds increases the tilt to the array to capture a little more sunlight.
There are other manufacturers with competing products, and they have similar designs.
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Not Visible From The Street
Many people like that flat solar panels are not visible from the street. If youre worried about your neighbors or city officials disapproving of your solar installation, a flat roof is a good option. You can also use plants or other materials to disguise the panels from view.
Another benefit is that flat roofs are more accessible and safer to work on than pitched roofs. If youre installing yourself, a flat roof is a good option.
The main downside of a flat roof installation is that its not as efficient as a slanted roof. A sloping roof will capture more sunlight throughout the day. If youre looking to generate the most power possible, a slanted roof installation is a way to go.
Flat panels become dirty faster than angled panels, so youll need to clean them more often to prevent reduced production. Most panels are not flat but angled enough to self-clean and allow water to run off.
Do Panels Always Have To Be Tilted On A Flat Roof
They don’t necessarily need to be. But, you get more energy flowing from them if you tilt the panels to the optimum angle.
Additionally, because of the damage from leaking, which we discussed above, it cannot be easy to find a guarantee for panels with a tilt of fewer than two degrees.
In the long run, It is preferable to have your panels installed at an angle. You may even alter the incline amount after the setup is complete, if you prefer, to match your energy output requirements.
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What Return Can You Expect On Your Solar Panels
The cost and return on investment of installing solar panels vary depending on your location, your climate, and any local or federal financial incentives that may be available. On average, however, most solar power systems in the US for example should cost you somewhere between $2.60 and $3.20 per watt generated.
Your exact annual savings will depend on your typical electricity consumption and whether youre selling power back to the grid, but most flat roof solar panels will earn back your investment within seven to nine years. When you compare that with an expected 25-year life expectancy for the units, youre starting to look at significant financial savings.
Considerations Along The Way
Rooftops usually have other mechanical units that need to be considered when deciding on the correct installation process. These units include outers for air conditioning, vents, exhaust fans, parapets, pipes, drains, and more. A careful plan will avoid any shading and maintenance issues when the time comes.
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Choosing The Right System For Your Flat Roof
As you can see, flat roofs are no problem for people who want to install solar panels. It does mean that you, the homeowner, will need to ask a few additional questions of your solar installer:
- Does the installer recommend an attached or ballasted system? Why?
- Review the structural engineering report of the roof with your installer. If they propose going with a ballasted system without doing an engineering review, this is a red flag. Find a different installer.
- What angle will the panels be at?
- Does the installer recommend a tilted system? Why, or why not?
As youâve hopefully learned from this article, thereâs no one right choice for all situations. Instead, work closely with your installer to understand the tradeoffs of different types of equipment. A good installer will take the time to carefully explain everything.
If youâre ready to make the leap and go solar, use the link below to get quotes from multiple qualified solar installers near you.
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Is Solar Panel Output Lower With A Flat Roof
No, solar panel output is not lower with a flat roof. While youll need to orient and angle your panels so theyre as south-facing as possible, tilting panels on a flat roof isnt difficult. And as weve already discussed, no matter the pitch of your roof , your panels will more than likely sit with at least some incline, even if its only a few degrees.
You may even get a more efficient angle with flat-roof installation since you can control the amount of pitch your panels have better than on a more traditional home roof with peaks and slants that might be more severe than is best for your panels.
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Solar Panels On Membrane Roof
Roofing membranes are PVC sheets that prevent water from leaking through a roof and into the building below. Thicker membranes are best for solar installation because they reduce fire risk and provide more support.
If one roof layer fails the whole system may fail, so correct installation of a high-quality membrane layer is essential.
Increased demand for sustainable energy has resulted in the development of roofing membranes with thin, built-in cells. These membranes are flexible, allowing for custom designs and less noticeable solar systems.
This design is helpful for flat roofs because it offers protection against pooling water while still generating power.
Benefits Of Installing On A Flat Roof
Installing solar panels on a flat roof is easier than installing them on the slope of one. The work crew will be able to move around freely without any specialized equipment and can even weigh down their installation with an additional mount that holds it into place, eliminating all need for drilling holes through surfaces!
Flat roof installation can be cheaper because there is no need for additional mounting or reinforcement and the entire process can be completed in a shorter time frame. Solar panels on flat roofs could also have an increased life span as well.
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Instructions For Installing Solar Panels On Roofs
Here are the pro tips when mounting solar panel systems on shingle roofs:
Step 1: Lay out the installation materials you need.
Make sure that all the materials necessary for installation are nearby. You surely wouldnt want to go from the roof and back repeatedly.
Step 2: Determine where the stanchions go.
Find the roof rafters with the aid of a stud finder or your homes blueprint. These will help you figure out the correct placement of the stanchions. Position the stanchions at least 4 feet apart.
Step 3: Fasten the screws to the roof.
When fastening the screws to the roof, utilize a drill to create holes in the rafters.
Step 4: Tightly put the screws in the holes and secure them.
It would help if you tightly secured the lower and upper aluminum rails to the stanchions. Utilize bolts to do this. Since optimal tightness is required, utilize an impact driver to achieve this.
Afterward, make sure that you seal the screws tightly to maintain the thermal envelope of your home. Substantially, thermoseal roofing is the most excellent way to execute this.
This approach will help keep an incredibly tight lock on your roof and prevent any elements from getting inside. Leakage is less likely to emerge if the stanchions are correctly installed.
Step 5: Gauge the distance from the rails.
Gauge the distance from the rails when installing solar panels. Put a measuring tape diagonally from the top of one rail to the bottom of the rail situated directly across from it.
Solar Systems On Flat Roofs Can Save Businesses Money
Not only can solar panels be installed on flat roofs, but they can thrive.
Depending on your specific roof, they can be installed with little to no roof penetrations, and they can be laid out in a manner that will optimize the production of free electricity. Theyll likely be out-of-sight from all but airplanes and birds, meaning you wont have to worry about them impacting the aesthetics of your building.
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Can You Install Solar Panels On A Flat Roof
Not every building has an A-line roof, and there are those of us out there whove had the audacity to build ourselves a building with a flat roof. While it looks great, and its something different, a flat roof can present a few obstacles to features common to many other buildings.
You can install solar panels on a flat roof, but to do so, youll have to make some adjustments that your pitch-roof owning neighbors wouldnt. But its possible, and by installing solar panels on your roofflat or otherwiseyou can do a lot to cut down on your utility bills and help even a little bit in the quest to preserve the environment.
Solar Panel Tilt And Performance
With penetrative tilt racks, panels can be placed at the optimal angle for annual electricity generation. In Sydney this would be around 31 degrees while in Brisbane it would be a less steep 25 degrees. But to reduce the amount of wind loading it is common for solar panels to be placed at less of an angle less than this, with 15 degrees being common. Ballasted tilt racks have a 15 degree angle at most and more commonly 10 degrees.
Fortunately, this doesnt result in much lost performance. Panels in Brisbane at a 10 degree tilt will have their output reduced by less than 3% compared to the optimum tilt, while in Sydney, solar panels at 10 degrees will only produce around 5% less than optimum.
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Is Different Equipment Required To Install Solar Panels On A Flat Roof
While you can just lay solar panels down flat against a slanted roof, there is some specialized equipment required to mount solar panels on a flat roof. Angled mounts help with sun exposure and energy output.
When I first started in solar installation ten years ago, I would often lay solar panels flat on flat roofs, something I am reluctant to do now.
There are now a lot of engineered tilt-up racking and mounting systems that can be used to tilt up the panels to an optimal level that cost little more than standard mountings used on a pitched roof.
How Much Does It Cost To Install Solar Panels On A Flat Roof
Generally, installing solar panels on a flat roof will cost more than on a pitched roof around 20% more, depending on the situation.
Of course, prices vary depending on a range of factors, including the number of panels you get and which mounting technique you use.
The key reason flat roof solar panel installations are more expensive is the extra cost of materials for the framing system and ballast weight. You’ll also usually need to hire a structural engineer, which adds to the cost.
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Disadvantages Of Flat Roof Solar Panels
While there are a number of disadvantages to flat roof solar panels, bear in mind that most of these can be resolved by using a tilted mounting system.
- Panels get far dirtier over time On a tilted roof, rainwater usually washes dirt and debris off the panels. Without this self-cleaning feature, the dirt will stay there, reducing the solar panels efficiency
- Without additional mounting equipment, panels wont get as much exposure Solar panels usually face southward on a tilted roof, in order to increase sun exposure and create more energy. Laid flat, panels are unable to convert as much energy because they will not be getting as much sunlight
- Flat roof panels can make some warranties ineffective When panels are laid flat, water sits between the frame and the glass coating of the module. Given this gap is only sealed with silicon, which easily degrades over time, panels are likely to become damaged faster than usual
- Wind effects are greater, which means your installer will need to be careful while designing the mounting system. Sometimes ballast weight is required, so you’ll need a structural engineer to check the roof can hold this extra weight.
