PV Mounting Above Roof Ridge

I have a house with an almost perfect southern exposed front roof, but there will be shading caused by an attached garrage roof line and two dormers. I thought the best option to get the full output of a PV system would be to mount the system on a rack above the roof ridge with a support structure tied in to the north facing (back) roof line. Has anyone done an installation such as this and is it approved by most building codes? Also will there be wind loading issues with this that can't be overcome? If youve done something like this what racking system did you use, and is there a standard rack from Unirac or one of the other manufactures that can be used for this type of installation?

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: PV Mounting Above Roof Ridge

    Pretty much you will have to ask a structural / civil engineer to do the analysis of your home and proposed structure to see if it will be safe.

    By the way--what about remodeling? Can you move the dormers to the "other-side" of the room/roof line? Can you replace them with operating skylights?

    It is interesting--once you start looking at solar panels--your eye for lot, home location, and architecture sure takes a 90 degree turn.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: PV Mounting Above Roof Ridge

    Anything can be done if you are willing to pay for it, (and the permit authority allows it!)
    My guess is that it would be quite expensive depending on how much over the ridge the array is going to be. Part of one panel wouldn't be too bad,,, but 3 tiers high might be a structural/maintenance nightmare. (On my own little system I have one set of panels that extend ~1/3 of their length above the ridge) My guess is that the cost is going to way out weigh the benefit.

    You might consider wiring the panels in a set of series/parallel sub arrays such that the ones that go into shade can be seriesed together such that they don't pull the whole string down. It might take a bit of messing around to get the optimal configuration. You might even consider having a way to change the wiring configuration seasonally to take best advantage.

    T.

    PS Post a picture of your roof/house maybe some smart guys here can come up with a better solution.
  • Ecnerwal
    Ecnerwal Solar Expert Posts: 101 ✭✭
    Re: PV Mounting Above Roof Ridge

    You're basically putting a big sail up there - So the licensed professional Engineer's opinion is required. If it's a big structure it will be a pain to work on, most likely. If it's 1/2 or 1/3 of one panel poking over, it might be fine. If your present roof structure is not overbuilt, it may need a lot of reinforcement, or it may just not be possible. Sometimes you simply need to accept that things are not practical - if putting panels up out of the shade will require a whole new roof structure, you'll be rebuilding half your house...probably not an economically sensible path.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: PV Mounting Above Roof Ridge

    Sounds like you need a carport !
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
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