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How are Solar Panels Attached to Your Roof?

Avatar for Ben Zientara
Published on 04/13/2017 in
Updated 01/17/2019
Different ways to mount solar panels to composite, stone tile, clay tile, or metal roofs

It’s ironic that the best place for solar panels (rooftops, yo) is also the most difficult place to mount them. Solar panels need a place that’s sturdy, unshaded, and pointed towards the sun, and roofs fit that bill nicely. You will want to do any roof repairs before installing solar panels. But getting up there can be a pain, and attaching panels to the roof means drilling huge bolts into the rafters by commercial roofing companies. Also, because of the huge variation in roofing materials and construction techniques, the solar industry has had to invent many different methods to attach mounting hardware.

Well, invent them it did, so whether your roof is covered in slate tiles, asphalt composite shingles, or cedar shake, you can find an installer who will use the right mounts for your roof and make sure to avoid any of this:

Water is coming through my vents! Ahhhh!

General Information about solar roof mounting

Solar panels are designed to be easily and durably mounted to racks that attach to roof mounts. The mounts themselves have to be drilled into your roof’s rafters, but not because the panels themselves are heavy. Instead, building codes call for protection from “upforce.”

Basically there is way more danger to the panels catching air like a sail and ripping off your roof than there is to them weighing too much and pushing through your roof. If they are bolted to the rafters then they are attached to the infrastructure of your house, and there are no worries.

They drill into roofs, don’t they?

The fear about roof penetration from solar installations is definitely one of the top concerns of people that are serious about installing solar panels, so let’s just clear the air. Yes, just about every solar installation will involve giant screws being attached your rafters, like this Fastjack:

A Fastjack solar roof mount

Unless you have a standing-seam metal roof, the mounting system will use bolts similar to this. To prevent water damage, the bolt fixture will be surrounded by flashing, which is a special metal or plastic shield that slips under the surrounding roofing tiles to prevent water from getting in. The flashing will be sealed with tar or underlayment, and the bolt hole will be filled with long-life sealant, as well.

Like we said above, installation practices vary by roof material. Here’s an idea of the unique challenges for each:

  • Clay or stone tile roofs sometimes require additional labor to remove tiles, install the mounts and flashing, and make cuts or grooves in the tiles so they don’t contact the mounting hardware
  • Wood shake roofs are easier to cut/drill into, but require flashing that extends far underneath the tiles higher on the roof
  • Asphalt composite shingles are easy to work with, as long as the installer can find the rafters
  • Standing-seam metal roofs are the easiest, requiring no penetration of the roof, because solar mounting clamps can be attached to the seams

What about when I need to replace my roof?

This is another big concern people have, and not without reason. Replacing a roof is expensive, and having to remove solar panels before you do it (and reinstall after) is a big deal, right? Well, kinda, so make sure to contact a roofing specialist before you start.

It costs about $1,000 (could be less or more based on installation size) to pop off existing panels to let a roofer do their thing, and then put them back on. And while it might be advisable to wait to install solar if you plan to replace your roof in the next few years, it might be more advisable to replace your roof sooner, and go solar before the federal solar tax credit expires.

Regardless, if you need remove panels to replace or repair your roof, call a NABCEP-certified solar installer to have the job done right. If you have a PPA or lease contract with an installer, look in your contract to see if they have any rules about who can do the work, or whether they’ll do it for you. The panels are their property after all.

Here’s a little more about mounting solar panels on each type of roof:

Solar mounts for tile roofs

A solar roof mount under Spanish tile

Mounting solar panels on most tile roofs works the same way: remove a tile or three, attach the tile hook and flashing, carve tiles out of the way, and replace the tiles where they were (you can see a tile hook covered by flashing in the image above). That holds true for concrete, clay and slate. The tools used vary by type, but not much.

Spanish tile roofs are the most expensive type to install solar panels on. The reason is installers have no choice but to walk on them, and inevitably break some of the tiles. The owner must have extra tiles lying around, or installers must be able to find a match ahead of time to be able to replace. There is also some added time spent both drilling through them and treading carefully upon them.

These days, though, solar installers have gotten pretty good at working with tile roofs. Just make sure you get something in writing before they begin the work, to make sure their insurance or warranty covers any damage to your roof.

Installing tile hooks for solar

Though the image above shows a tile hook installed under S-shaped tiles, but the method of installation is very similar for other types of tile roofs. Here’s a great video from our friends at Quick Mount PV that shows how tile hooks are installed:

One way to avoid the need to cut or grind the tile is to use tile replacement mounts, which take the place of the tile under which the mount is attached to the roof.

Solar mounts for wood shake roofs

Solar mount with flashing on a wood shake roof

Wood shake shingles are a fun way to cover a roof, and they work pretty well, too… until you start putting holes in them.

Solar installers need to be particularly careful when working with shake roofs, because the shake pieces can be brittle, but the actual installation of the mounts isn’t that complicated.

Nearly all shake roofs are made in the same way, with layers of underlayment between the rows of shakes. That means an installer just needs to get flashing up under the previous layer of underlayment and ensure a good seal. The picture above shows how a properly-seated flashing looks as it extends underneath the rows of shakes.

Solar mounts for asphalt composite roofs

Solar mounts in a composite roof

Asphalt composite roofs are popular. Heck, you’ve probably got one over your head right now. They’re relatively inexpensive, simply constructed, and generally very durable. That makes them a great surface on which to install solar panels. As long as the installation is done right.

Mounting solar panels on asphalt shingles is similar to mounting under cedar shake, in that the installer will insert flashing under the previous layers of shingles to maintain water-tightness, then seal the hole into which they’re screwing those giant bolts. When done right, it looks like the image above.

When done wrong, it looks like this:

A real ugly job done for a solar mount on a composite roof

That sealant might hold for 25 or 30 years up there, or at least as long as it needs to before the roof is re-shingled in a decade, but it’s ugly, and it probably voids the roofers’ warranty. You don’t want your home’s watertight integrity to be beholden to that crappy craftsmanship (crapsmanship?), do ya?

Solar mounts for standing-seam metal roofs

A solar mount on a standing-seam metal roof

Standing-seam metal roofs are awesome. They look good, they’re watertight, and they last for 50 years without much trouble. Oh, and those seams are the perfect place to clamp solar mounts, without drilling into the roof.

The longevity and ease-of use makes standing-seam metal roofs the perfect roof for solar panels. Once your panels are up there, aside from the occasional cleaning, you probably won’t need to worry about them much for the next few decades. And of something does need to be done to the roof, the panels are easier to remove and replace than on any other type of roof.

On top of all that, the spaces between the seams act as channels for air circulation, which makes your panels more effective by cooling them off during the day.

Isn’t it purdy?

The future: Boltless? Roofless?

Now it’s time to look ahead. Tesla’s got that pretty looking solar roof, which means your solar panels become your roof. They’re made of glass that’s designed to look like clay, cement, or slate tiles:

Tesla's solar roof tile types: spanish, slate, etc.

But the solar roof tiles are better for new construction. Even if you’re going to replace your existing roof, the substrate might not be ideal for Tesla’s tiles, and retrofitting would likely add thousands to the cost.

Another up-and-coming invention is a unique kind of ballasted solar rack that sticks to sloped roofs like a lizard’s feet stick to a window. The installation uses heavy frames with a special kind of polymer that grips the roof surface tighter as pressure (from the panels or wind) increases.

So the future of mounting solar on roofs might be bolt-less. Or it might be solar roofs. Or it might not be either. It’s too early to tell, and it’s almost always better to start saving money on energy today.

Last modified: January 17, 2019

22 thoughts on “How are Solar Panels Attached to Your Roof?

  1. Avatar for Roof Cleaning Auckland Roof Cleaning Auckland says:

    I am looking for transforming my place to run by solar energy, this blog will be really helpful for me. I am learning more about it, there are many blogs I have read of those people who have installed this in their house. Thanks for sharing your project!

  2. Avatar for paul paul says:

    We have just had solar panels called “amerisolar” fitted directly onto the roof tiles of our Spanish villa and the Inverter fitted onto a south facing wall in full view of the sun,is this acceptable ?

    1. Avatar for Spunc Jester Inc Spunc Jester Inc says:

      This is entirely wrong.

  3. Avatar for Luke Luke says:

    Hi Ben, do you have any information for flat roof installations? There seem to be ballast systems… do they “just work”?

    1. Avatar for Ben Zientara Ben Zientara says:

      Hey Luke-

      Thanks for asking. Ballast systems can be as simple as “they just work,” but they’re often more complicated than that, because they add weight to the roof and sometimes aren’t allowed under local building codes. Regardless of whether the racks are anchored to the roof or to ballasts, panels on a flat roof need to be tilted, which adds a small amount of money to the final cost of the system.

  4. Avatar for Dan Paterson Dan Paterson says:

    I like the comment you provided it tells me how solar power panels are placed on a roof!

  5. Avatar for Hassane Mossi Hassane Mossi says:

    I wish you can export this system in Niger (West Africa))

  6. Avatar for Bob Wagner Bob Wagner says:

    angled panels on our roof – 4 months later with a series of heavy rains, our roof leaked in numerous places. They did not use any kind of special bolting system, nor did they coordinate with a roofer. Do you have any suggestions on how we can get this problem fixed before it rains again?

  7. Avatar for Tom Braga Tom Braga says:

    How many KWS needed to heat 4500 Sq ft heated area.How many panels and how many inverters needed??

  8. Avatar for Jeff Jeff says:

    A few questions:What do you recommend for an installation on top of a light weight concrete tile roof? The tiles are very fragile so it is not clear how the panels could be anchored without causing damage. T

  9. Avatar for George Dillmann George Dillmann says:

    What if I decide at some point that I don’t want the panels any longer? Then I have all these punctures in my roof. Can they be filled in so completely that it can be guaranteed that there won’t be any leaks?

  10. Avatar for Tor a.k.a. "Solar Fred" Tor a.k.a. "Solar Fred" says:

    Steve, I’ve never heard of anyone complaining about wind noise from solar. Never. If the wind in your area is blowing that hard, it’s going to make noise no matter what.

    Your panels must be installed with framing a certain amount above your roof, that’s true. I’m really not sure of the minimum amount. However, you are right: Panels like to be cool and work best raised above the roof line. Having them flush against your roof is a no-no, even if it looks “better” more flat. That being said, it’s a typically minimal amount above your roof.

    Good luck with the install and thanks for going Solar! You rock.

  11. Avatar for Steve Steve says:

    I appreciate the info that I read on here.

    I am about to install (or possibly have installed) a 10kW system on my roof that is almost 60′ long. Do you have any suggestions how to ensure the installation is quiet and that I do not have expansion or wind noises from the aluminum framing? Also, is there a minimum distance off of the roof that the solar panel needs to be mounted for heat dissipation? I am trying to learn everything well in advance and appreciate any advice. Lastly, I cannot fit enough Sharp panels so I am looking at Sunpower and Sanyo which have smaller footprints. Any suggestions or alternate companies?

    Thank you,

  12. Avatar for Phyman Phyman says:

    We will soon be purchasing a house that has a great southern exposure and will require a new roof. You mentioned that a solar company can come in while the roof is being done to install the mounts before the roofing installation is complete but I’m wondering if there is any advantage to doing that. Does it make for a cheaper solar install or simply make it more secure b/c the installer doesn’t have to search for the studs? Are roofing companies really cool w/ stopping their work while another team goes up (if time is money)?

  13. Avatar for Randy Randy says:

    Hi David:
    I am about to install a 4 kw solar Do it yourself system. I have done lots of reaserch and i would like to use the pro solar fast jacks for mounting to our s-curve concrete tile roof . I under stand about removing the tile and mounting the fastjacks to the rafters and then sealing , but what is the best way to do the flashing,, do you drill a 1″ hole in the concrete tile and then use metal flashing,, thanks for your help

  14. Avatar for Yasser Yasser says:

    Hi David:
    Thanks for your useful articles. At the beginning you mentioned that leaking is one of top three concerns of your customers. Can you please let us know what two other concerns are? Thanks

  15. Avatar for Lucy Lucy says:

    Tilting the panels is our biggest problem. My husband and I are just too old to be climbing up there to do such things.
    Here is a great article on solar panel tilting which I found helpfull.

  16. Avatar for david david says:

    We have a flat roof with a EDPM rubber over high density foam that is 3-4″ that is screwed into the plywood overlay. It is a two story modern contemporary house. We have an unobstructed southern sunshine that can generate a lot of solar energy. I’m afraid that if you anchor the panels to the EDPM there will be leakage. What is your solutions if there is one for this type of structure?

  17. Avatar for David Llorens David Llorens says:

    for perfect tilt, do a google search for magnetic declination. Like I said, perfect tilt matters almost nothing. in SE just shoot for 15 degrees or around there.
    I find that when people use special racking systems that allow for a summer/winter adjustment… they end up saying ‘screw it’ and never adjust the thing, leaving it optimized for summer or winter year round.

  18. Avatar for David Llorens David Llorens says:

    the racking system we used to use only went to 12 degrees if you stuck two panels in portrait. You’d be surprised how little difference optimal tilt matters as long as you’re withing 10 degrees. More important than tilt is orientation, and WAY WAY more important than orientation is shading.

  19. Avatar for Dan Hahn Dan Hahn says:


    We recommend ensuring that whoever is up on your roof doing the installation knows what they are doing. Fastjack bolts or similar need to be drilled directly into the joists in your flat roof. That can take a little bit of time. Optimum panel tilt depends on your latitude. If you’re in the Southeast US, I’d say something like 20-30 degrees. Check this with local installers though. Orientation = south.

  20. Avatar for TC TC says:

    What do you recommend for a flat tar roof as far as attaching the mounting system? and what are the best ways to get the exact angle needed for maximum efficiency. In the Southeastern US

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