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diy solar

mounting over roof vents and plumbing vents

Subestile

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Joined
May 17, 2022
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I read though some code p3103.1 that now allows for installation over plumbing vents as long as there is enough spacing between the top of the vent and the panel and now the vents can be cut to 2" above the roof line. I will likely reroute these to go out the top of the panels so I dont have that venting onto the back of the panel. I tried looking for any existing posts if anyone has mounted over the attic exhaust vents though? being in az I cant imagine the heat from those will be significantly more than what the panel already gets exposed to. Is there any issues with mounting over the vents? I am running out of useable space on the roof attempting to maximize the production of the system. Thanks for any feedback
 
I had the grid tie system on my roof done by a local company. On the original quote, there were a few panels missing in the drawings. When I questioned this, I was told there were vent pipes there. I requested they cut the vents so They were about half way between the roof and bottom of the panels. Like I sad, zero issues.
 
I had the grid tie system on my roof done by a local company. On the original quote, there were a few panels missing in the drawings. When I questioned this, I was told there were vent pipes there. I requested they cut the vents so They were about half way between the roof and bottom of the panels. Like I sad, zero issues.
Ill be installing my second system, the original system didnt have any issues with vents as it was completely over a living room and bedroom. but adding 19kw (hopefully, im running out of space) to my existing 7.4kw system.
 
anyone knows if termination of vent pipes under panels is allowed in California? Trying to use this method in PGE territory.
 
We were trying to figure out how to work around a vent pipe and the foreman took a piece of chalk-line string and used it as a saw to cut the PVC vent pipe off a couple of inches off the roof. #ProblemSolved.
 
Same here, panels are over the bathroom exhaust - about 3"? - all is OK after 7 yrs.
However, I did put the panels around a plumbing vent that was sticking up at same height as panels - no shadow issues and was able to avoid the furnace exhaust.
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yea, I also suspect the PV panels won't suffer from vent pipes opening under them. I am concerned about how California inspector will react to this arrangement. I am not even sure if they care or even review the installation on such a detailed level to notice or care about vent pipes...
 
Installed solar last year in Placer County and was told roof vents can not be covered with panels. Another option, a grey area in California, is to simply cap the vent pipe in the attic and install a Studar Vent. Cant remember exactly Studar vents requirements. ie need to be accessible, can be in attic or in a cabinet

Hard to say if the inspector would notice panels over vents. The inspector did not get on a ladder but did walk around and take a good look at the panels.

Also, roofs do move, sag, and depending on the age and roof vent jack, their could be a leak between the vent pipe and jack. This happened to me a couple years ago. Accessing the leaky jack under a panel would be a pita.

Given all the above, I relocated the roof vent.
 
My vote goes to @timselectric for the best solution... ;)

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See... https://diysolarforum.com/threads/d...-partial-shading-situations.59840/post-737372
 
anyone knows if termination of vent pipes under panels is allowed in California? Trying to use this method in PGE territory.

In early 2016, Solar City installed 5kW on my roof, and cut off the plumbing vents under the panels.

I'm in Huntington Beach, and it passed inspection.

They did *not* mount panels over my eyebrow vents from the attic.
 
Ack. People do not take the sewer vents seriously.

"Sewer gas" can contain hydrogen sulfide (H2S). Mixed with air (oxygen) and moisture it can become sulfuric acid (H2SO4).

I have seen holes corroded in the bottom pans of A/C rooftop units installed right over the vent (I was called to diagnose the "sewer odor"). Technically a code violation here in PHX., but it happens when lazy A/C installers crane up a new unit that doesn't fit in the footprint of the old.

So, keep this in mind. The backing on solar panels tends to be some kind of plastic, but anyway...
 
My main line has a belly which is a low spot in the sewer line I can see water in the main looking down the cleanouts. Every once in awhile I have to dump some draino down there get rid of the smell. I got a quote wanted 10k to replace the line I can buy 55 gallon drum of draino for that much it's only couple times a year. I wouldn't cut my vents off and put them under something likely house would start to stink. I would reroute them so they are not under anything. I'm going to get the main fixed at some point not high on the priority list rather spend the money on a DIY solar system.
 
good day, a question from an uneducated person hehehe sorry for this question.

does mounting solar panels on plumbing vents has major side effects? hope there's someone out there can answer me..
 
anyone knows if termination of vent pipes under panels is allowed in California? Trying to use this method in PGE territory.

1. I recommend making sure roof condition is good for expected life of panels. if not, re-do roof first... and if I had it to do again, I'd have insisted on consolidating a number of plumbing roof vents when I had the roofing work done (would have been relatively cheap/easy with large open attic space to work in, and lift 'n 'lay involved wood replacement already).
2. not that different jurisdictions can have their own rules/interpretations regarding vent pipes and solar panels. This is NOT a PG&E question, but for your local AHJ (residential building code enforcement jurisdiction authority). And plenty of stories of building inspectors not following the rules... so ymmv.

the CA code for the top of the vent height above the roof recently (last 3 years?) decreased, in part to accommodate solar installs [from what I've read]. I used these as reference these articles from Nov '22
  1. https://solvoltaics.com/plumbing-vent-under-solar-panel/
  2. https://www.thesolarnerd.com/blog/how-to-install-solar-panels-over-plumbing-vents/ Last updated: November 14, 2022
which includes

Installing solar panels on top of plumbing vents​

A plumbing vent is a small pipe that allows air to enter drain pipes or sewer gases to escape. They are small, usually between 1-1/4 to 4 inches in diameter. Local plumbing codes will dictate how high above the roof surface the vent must rise. A common requirement is that the pipe must rise six inches above the roof. For example, California Plumbing Code section 906.1 states that “Each vent pipe or stack shall extend through its flashing and shall terminate vertically not less than 6 inches (152 mm) above the roof”.​
In snowy climates, it’s common for the requirement to be six inches higher - that is, a full foot above the roof. If you happen to live in a municipality without any such code, it may be possible to install solar panels right on top of your plumbing vent. A rack of solar panels sits about 5 inches above the roof surface. Where permitted, the vent pipe can be cut down to just a few inches above the roof surface so that it can sit in the space underneath the panels.​

what gets tricky is your roofing material... is Spanish S-Tile and vents come out in the valley... then distance above top of S-Tile doesn't have to be that much...
 

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