User Tag List

Page 1 of 2 12 LastLast
Results 1 to 10 of 11
  1. #1
    Setting Up Camp
    Join Date
    Oct 2020
    Posts
    17
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Best way of finding roof joists for solar installation

    I’m in the process of installing my solar array and want to ensure my thinking is right. Am I right to assume that the visual line running width wise about every 24 inches are the joists? Guess I would have assumed closer to 16” being that you can walk on the roof. Also, anyone know how thick the sheathing is?

    Thanks!

    EDIT
    Okay, so I’m way off lol! The “lines” that I’m referring to are 48” apart so assuming those are the edges of the sheathing. I’ve taken a stud find up but it doesn’t seem to be able to detect the joists.
    Last edited by TheGould; 05-16-2021 at 11:53 AM.

  2. #2
    Site Team Ynot4me2's Avatar
    Join Date
    Mar 2020
    Location
    ON & QC Canada
    Posts
    1,916
    Mentioned
    11 Post(s)
    Tagged
    0 Thread(s)
    Get a fat guy like me to walk on it and see where it sags. When I walk on mine I can tell where they are.

    Sent from my SM-P610 using Tapatalk
    Steph & Lise
    2019 F150 Lariat 2.7 EB
    2020 Imagine XLS 22MLE

  3. #3
    Setting Up Camp
    Join Date
    Oct 2020
    Posts
    17
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Lol, are you for hire?

  4. #4
    Site Sponsor
    Join Date
    Feb 2018
    Location
    SW Colorado
    Posts
    1,935
    Mentioned
    21 Post(s)
    Tagged
    1 Thread(s)
    Get a GOOD stud finder. Sheeting is 3/8 so should work. There will be a joist where the plywood seam is, In between - pull the trim ring on a skylight or vent and measure. You can also use a rubber mallet and gently tap.
    Last edited by powerscol; 05-17-2021 at 07:29 AM.
    2018 Reflection 150 Series 220RK 5th wheel. Reese R20 Titan hitch, Steadyfast system, 2004 F350 6.0 Diesel King Ranch dually, Trailer reverse lights, rear spare tire holder, storage tube, sumo springs, Victron MultiPlus and Solar

  5. #5
    Site Sponsor RoJoSo's Avatar
    Join Date
    Nov 2019
    Location
    Lehigh Valley PA
    Posts
    226
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by TheGould View Post
    I’m in the process of installing my solar array and want to ensure my thinking is right. Am I right to assume that the visual line running width wise about every 24 inches are the joists? Guess I would have assumed closer to 16” being that you can walk on the roof. Also, anyone know how thick the sheathing is?

    Thanks!

    EDIT
    Okay, so I’m way off lol! The “lines” that I’m referring to are 48” apart so assuming those are the edges of the sheathing. I’ve taken a stud find up but it doesn’t seem to be able to detect the joists.
    Assuming the rig is outside. On a "dewy" morning, go up on the roof and you will see exactly where the joists are located.
    Good Luck with the install. Share your work with the rest of us.
    2020 Grand Design Reflection 303RLS 5th Wheel
    2013 Ford F250 Super Duty, King Ranch, 6.7 Diesel, HD Tow Package
    B&W Companion Slider RVK3405
    Timbren Rear Suspension Enhancement System R250SDG

  6. #6
    Setting Up Camp
    Join Date
    Oct 2020
    Posts
    17
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Iíll run the stud finder over it again - it is a pretty good one. Like the dew trick as well, thanks.

    Been debating diarizing the build, Iíll start a dedicated thread to capture the process.

  7. #7
    Site Sponsor
    Join Date
    Feb 2018
    Location
    SW Colorado
    Posts
    1,935
    Mentioned
    21 Post(s)
    Tagged
    1 Thread(s)
    Please do the thread on the roof install. Ill be needing help on mine. I have a thread at the other place going through my equipment installation. Already made a few mistakes that I documented. Hint when spacing out equipment/switches, install the lugs to make sure you have clearance and room to bend cables. Otherwise flat copper bar stock (1" by 1/4") will work and make your own.

    Thanks
    2018 Reflection 150 Series 220RK 5th wheel. Reese R20 Titan hitch, Steadyfast system, 2004 F350 6.0 Diesel King Ranch dually, Trailer reverse lights, rear spare tire holder, storage tube, sumo springs, Victron MultiPlus and Solar

  8. #8
    Big Traveler geotex1's Avatar
    Join Date
    Sep 2019
    Posts
    1,869
    Mentioned
    40 Post(s)
    Tagged
    0 Thread(s)
    Very hard to find with conventional stud finders because the decking is stapled down, and the staples are always countersunk. If you know a pro with a radar or sonic, it's super fast. Personally, I would not use a common 1/4" lag through the trusses because you'll split the 1x2 top chord of GD trusses pretty badly. I would use a self-drilling construction screw. Nova is a good brand of structural screws of this type. The self drilling tip clears the cuttings from the hole greatly reducing the chance of splitting.
    Rob & Nikki + Cloverfield
    2020 Grand Design Solitude S-Class 3350RL
    2015 RAM 3500 Longhorn Laramie Crew Cab, Long Bed, 4x4 Dually Cummins/AISIN

    Mountains of Pennsylvania

  9. #9
    Site Sponsor
    Join Date
    Feb 2018
    Location
    SW Colorado
    Posts
    1,935
    Mentioned
    21 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by geotex1 View Post
    Very hard to find with conventional stud finders because the decking is stapled down, and the staples are always countersunk. If you know a pro with a radar or sonic, it's super fast. Personally, I would not use a common 1/4" lag through the trusses because you'll split the 1x2 top chord of GD trusses pretty badly. I would use a self-drilling construction screw. Nova is a good brand of structural screws of this type. The self drilling tip clears the cuttings from the hole greatly reducing the chance of splitting.
    Rob - good tip.
    I plan to predrill my holes and place lap sealant in the hole before installing the lag bolt for extra sealing.
    2018 Reflection 150 Series 220RK 5th wheel. Reese R20 Titan hitch, Steadyfast system, 2004 F350 6.0 Diesel King Ranch dually, Trailer reverse lights, rear spare tire holder, storage tube, sumo springs, Victron MultiPlus and Solar

  10. #10
    Seasoned Camper jleonard's Avatar
    Join Date
    Jul 2020
    Location
    New Port Richey Florida
    Posts
    243
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by TheGould View Post
    I’ll run the stud finder over it again - it is a pretty good one. Like the dew trick as well, thanks.

    Been debating diarizing the build, I’ll start a dedicated thread to capture the process.
    Please let us know how the stud finder works. I may want to do this someday. Thanks.
    Jay Leonard
    New Port Richey, Fl
    2021 Imagine 2600 RB, 2021 Ram 2500 CC Bighorn 6.7L Cummins

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

DISCLAIMER:This website is not affiliated with or endorsed by Grand Design RV, LLC or any of its affiliates. This is an independent site.