I just built a new home. Solar panels on the roof. Roof uses foam insulation and the inside of the home has a cathedral ceiling. Wood shingles No attic. Solar panels are making a loud banging noise - typically early morning or early evening when outside temperature is changing. Much louder than typical house settling. Sometimes wakes me at night. Installers can't figure out why. Any experience with this out there?

I assume these are rack-mounted? Perhaps the panels are expanding/contracting from thermal effects until the stresses are enough to allow them to "slip" or "pop" in the supports. At that point your cathedral ceiling is nothing more than a drumhead amplifying the noise. Pure speculation on my part as I am not an installer. I am sure someone more experienced will reply eventually. You may want to repost your question in the solar and wind power forum.

How old is the system and has it been doing it since new? There are a few possible reasons for this.

Thank you. We are just now finalizing the home. The panels have been up for about three months. The panels have now been taken down - but I'm still hearing the banging - I think from the aluminum racks. We're now taking the racks down to see if the noise stops. When one of the builders pulled on a rack and then let it go - we got a similar banging sound.

You are right - any noise up there reverberates throughout the house. Foam insulation may be making the noise worse. I have a ground solar array as well. Wish I had placed all the panels in the ground array. Provider pushed hard for the roof - indicated its much more cost effective. They may have to eat their words unfortunately. One person said the banging might be from the icynene foam detaching from the studs - but I think we've confirmed that is not happening.

The noise you have is very rare so i wouldn't condemn the roof mount yet but I would look into why the rack makes the noise in the first place. Perhaps moving the mounts would help or perhaps the bolts are not in the joists properly.

Thanks. Has anyone experienced these sounds from icynene insulation pulling from studs?

If you have racks that are bolted together, welding them might help. Or go the other direction and add nylon washers so it can move quietly.

Metal roofs have a period in which the metal needs to find a comfortable way to expand and contract with temperature changes. Over time, they settle down, if installed correctly.

Large roofs and long pitches magnify the effect. In addition, aluminum has twice the expansion coefficient of steel. If you have the mounts fixed together in long arrays you might want to break them up a bit. See if you can identify a horizontal member or two that can be loosened without compromising the underlying integrity. That should allow smaller sections to move with the expansion.

Did you ever figure out what was causing this noise? Our panels went up a couple months ago and we're experiencing the same problem. Our installers are stumped and say they've never heard of this happening before. It's really disruptive to our sleep but we're happy with the panels otherwise!

Did anyone ever figure this out? We have a cathedral ceiling too and constant knocking day and night.
Thanks for any help or hope you can give us.

If you have racks that are bolted together, welding them might help. Or go the other direction and add nylon washers so it can move quietly.