Racking options extremely steep roof. 55

[wallyllama]

my south facing (180+- 5) roof is about a 14:12 pitch, inclinometer says 55

[foo1bar]

my south facing (180+- 5) roof is about a 14:12 pitch, inclinometer says 55

I believe that the usual racking solutions still work at steeper pitches.
Is it a typical asphalt composite shingle roof? Or something else?
That's probably going to make more of a difference than the slope.
The slope is mostly just going to mean that it'll be a pain to do the work because it's not an easily walkable roof like a 4:12 pitch.

[littleharbor]

And production might be better in the winter than the summer. What latitude are you at?

[wallyllama]

typical asphalt shingles, 2 yrs old. about 42.5 N lat.

I was sort of guessing/hoping that the standard racking would be up for the job, maybe more anchor points, but the documentation all stops at 12:12 slope, so I suspect my local planning dept. will balk. I guess I just need someone that can say the roof can handle the forces and the forces aee within spec of the racking? <-- that is a question disguised as a guess.

I have some west facing roof at about 25

[foo1bar]

I was sort of guessing/hoping that the standard racking would be up for the job, maybe more anchor points, but the documentation all stops at 12:12 slope, so I suspect my local planning dept. will balk.

Are you planning this as a DIY job?

If not - it's your installer's problem.

If you are planning to DIY - I'd contact Ironridge or Unirac and ask them. "Hi. I am putting together a proposal for a solar install on a 14:12 pitch, composite shingle roof in Springfield Montana. I usually would use your online tool to get plans for the racking. But the tool only goes up to 12:12 pitch. Do you have any resources that can help me with this 14:12 pitch roof? It will be 3 rows of 8 LG285S1CG4 modules in portrait orientation. Thanks."

[Ampster]

If you are doing this as a DIY job there are roof jacks that could make working on this a lot easier. This would be an interesting plan to model with that pitch that favors winter at your latitude. If you have a Time of Use rate that favors late in the day generation I would consider also using some of that western facing roof.

[wallyllama]

I mananged to delete 1/2 my first post, I have contacted iron ridge and another company, both said basically Im going to need an engineer. I was hoping for diy, so not easily passed off to an installer. Im not worried about working on the roof myself, the needed safety gear is available dirt cheap these days, and most of the area I would work on the roof goes nearly to the ground.(think a frame)

[Ampster]

Hopefully you find the right engineer. It might only mean a few more attachment points to account for the greater shear load.

[khanh dam]

there was a thread a few days ago about hiring engineering, they are not cheap typically $500 to $1000

[J.P.M.]

Hopefully you find the right engineer. It might only mean a few more attachment points to account for the greater shear load.

Depending on how far along the design might be, if it looked like the difference in loadings might be small, and if/as long as the project will use an engineer, if I was that engineer of record, I'd start by seeing what the difference in applied loads might be for dead and occasional, including wind and seismic loadings and their required loading combinations for a 12:12 pitch vs. a 12:12 pitch. I'd then see if the existing ("standard" ?) design can handle the different loadings as incurred for the 14:12 pitch before I did any changes that might require changes and so more expense.

At he end of the day, my guess is if a P.E. is required, (s)he will wind up doing the loadings for the 14:12 pitch and then, as you suggest, possibly use more supports after checking allowable stresses for all the racking components to see, in the P.E's opinion, what's the best way to use standard racking in what may be a slightly off design way.