East West racking solution? Foam adhesive for racking?

[fraser]

1) Where can I buy East West mounting for residential flat roof

I've run the calculations on PVwatts and a system will only produce maybe 15% less using East West mounting vs optimal tilt but I would lose much more than that in row spacing. For example a 30 deg tilt would require a 34.6" space between landscape tilted 72 cell panels, resulting in a loss of nearly half of my available roof space. 15degree tilt I lose 22% of my roof space. As a result, to maximize solar output from my roof a flat or East West mounting system will produce the most solar. However, I can't seem to find a residential east west mounting system. Can anyone recommend one?

2) Can I use foam adhesive for attaching racking to my flat roof in California?
I've seen 2 solutions, including one approved in Florida whereby the racking is installed with foam adhesives used for roof tiles and is rated for hurricane force winds. Is there anything similar that is allowed in California? The system is called solar stack.

[solarix]

Do not mount your PV panels flat or you will be up there cleaning them a lot. Panels need at least a 15deg tilt or they won't wash themselves in the rain and will get dirty and stay dirty. Yes, panels on flat roofs use up a lot of space and flat roofs usually have lots of obstructions and are cut up into little pieces by the architects. Do the best you can to shoehorn in your array. With most inverters having multiple inputs, at least you can have multiple orientations and still be optimized.
Foam adhesive is probably going to void your PV panel warranty as they will overheat.

[fraser]

Do not mount your PV panels flat or you will be up there cleaning them a lot. Panels need at least a 15deg tilt or they won't wash themselves in the rain and will get dirty and stay dirty. Yes, panels on flat roofs use up a lot of space and flat roofs usually have lots of obstructions and are cut up into little pieces by the architects. Do the best you can to shoehorn in your array. With most inverters having multiple inputs, at least you can have multiple orientations and still be optimized.
Foam adhesive is probably going to void your PV panel warranty as they will overheat.

So, east west mounting comes standard with a 10 or 15deg tilt, east and west, so they will self clean, mostly. The foam adhesive would go on the racking, not the panels directly, so again, that would not be an issue. It seems to me though, that using non-penetrating attachments would be the gold standard.

[littleharbor2]

Look up "Ballasted racking" solutions.

[Calsun]

In California the racks need to be attached with fasteners as the concern is with lateral movement during an earthquake and the lack of a perimeter wall or parapet on a house.

For any adhesive that is used it is best if it is silicone one and not a polyuretahane one as these will half half the service life of the silicone.
Panels lose less output from tilt angle than most people appreciate. They are designed to accept a lower incident angle and still provide power. Optimum tilt depends on whether you want maximum output over a 12 month period or maximum during the summer months. The rule of thumb of having the tilt angle the same as the location's degrees of latitude is a not a bad guideline.

My panels are on a flat roof and I designed the racking to provide a tilt angle for the front row to minimize shading of the second row (to the north) which could be at a greater angle. I had the first row mounted in a horizontal orientation to avoid shading of the rear panels and the second rear row of panels was mounted vertically.

The two rows needed to have sufficient space for a fire fighter to get up on the roof in the event of a house fire. I needed to have my panel installation inspected and approved by the local fire department before it could be signed off by the building department. This is covered in my area in the fire codes (along with the need to have a cut-off switch that can be accessed from the ground).