Vlog Series: Locating the Rafter

Today we’re posting our first in a series of video blogs! This vlog series will discuss challenges solar installers face on the roof and offer solutions to many of the common problems you may run into when installing rooftop solar. Our first post is about locating the rafter on a particularly challenging comp/asphalt shingle roof.

We’d love to hear from all of you about your experiences with challenging installations and how you ensured the project was a success. Or if you have a subject you’d like us to cover in this series, comment on the post and we’ll follow up with you. Hope you enjoy it!


  1. says

    Nice work on your first vlog, Jeff. Very helpful. I’m going to check out that Bosch stud finder. I like the combination of the email mallet and exploratory drilling. Measuring can be hard when the rafter top chords are not perfectly spaced from eave to peak and you end up exploratory drilling anyway.

    Maybe in a future vlog you can go into locating rafters on tile and metal roofs.


    • Jeff Spies says

      Jason, rafters in tile is easy once you remove the tile. Since you have to flash at the underlayment level on tile, it makes sense to reroof in most cases. Then a standard stud finder will often do the trick, but the Bosch D-Tect 150 makes an easy job of pinpointing the center of the rafter. The same is true for metal shingles which must be removed, making finding rafters easy.

  2. says

    Thanks Sue and Jason.

    When you get your Bosch D-tect 150 stud finder, do some testing over rough and smooth surfaces to better understand the wheel slippage problem. The tool will tell you when wheels are lifting or slipping, but minor lifting/slippage may not be detected resulting in a reading that is less accurate.

    The flatter the scan surface, the better the accuracy. The cardboard surface seems ok for three-tab shingles, but architectural shingles (presidential, multilaminated, sawtooth, etc) may require some additional shingle piece cut to fill the void areas before scanning.

  3. says

    Nice work, Jeff!

    Years ago at SPI I made identifying the world’s best stud finder my mission. The consensus was the Bosch unit and with great anticipation we bought one – only to have it be an utter fail on our next project which was a vaulted ceiling with the type of roofing you describe plus a layer of rigid insulation. Ugly! We sent it back.

    Now days we use a mixture of the other three methods – though the gadget geek in me is intrigued by the thermal imaging approach!

    • Jeff Spies says


      The big problem that most people (including me) have when using this unit is the roller wheels on all four corners need to be in contact with a flat surface. This means on shingles placing a piece of cardboard or another section of shingles turned upside down. This creates the smooth rolling surface for the tool to work.

      The video you see was shot on a roof with two layers of shingles, solid wood sheathing, and skip sheathing before getting to the rafter. I placed a section of heavy cardboard over the shingles and took the reading watching for any possible wheel slippage.

      The key to the Bosch D-Tect 150 is not having wheel slippage. This causes may people to give up on it when they first try it.

    • Jeff Spies says

      Aur, Sue Stark (East Coast Training Tech) tried one of those gizmos and it did not work reliably. Based on her experience, the iPhone IR adapter is not reliable for finding rafters.

  4. ethan says

    i really like your blog. thanks Jeff. it is challenging finding the rafters.
    i should check the website first, but, what do you think about the plug and play GTI’s ? They have anti- island protection. i like two dedicated circuits to the panel. one array for each phase.

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