STAINLESS STEEL solar panel mounting brackets

Xizang

I've bought several sets of these Stainless Steel solar panel mounting brackets and I'm totally impressed with their thickness, quality and prices.   I just thought I would share my good fortune at finding a product and seller I'm completely pleased with.

(And no, I'm not associated with the seller in any way - I'm just a happy customer)

http://www.ebay.com/itm/111776430129?_trksid=p2060353.m1438.l2649&var=410788438599&ssPageName=STRK:MEBIDX:IT

DavidOH

What a great find !   Mr Stainless has a good thing going. They look like high quality, and have to be stronger than the same gauge aluminum.

Photowhit

An inch and a quarter is not tall enough! maybe okay for an RV, but roof mounting should be 4" minimum to prevent heat buildup!

Xizang

I agree that the stainless steel is a lot better choice than aluminum.  Even just where the brackets are attached to the roof - aluminum will stretch and distort, stainless not nearly so much.

Xizang

Photowhit said:

An inch and a quarter is not tall enough! maybe okay for an RV, but roof mounting should be 4" minimum to prevent heat buildup!

That's a good point.   But I'm wondering if anyone's done any real studies on how much airflow is required to keep the panels vented.  And if 4 inches is better than 1.25 inches, then wouldn't it be required to mount all solar panels out on open air frames on poles, etc. and prohibit all rooftop installations?

Photowhit

Yes there have been studies, we've had one posted here in the past. It has to do with the heat buildup and losing production from the lower voltage.

I wouldn't worry about the aluminum, your panels framing is aluminum. If it's thicker than the framing, You would suspect the framing would fail before the aluminum mounts.

mike95490

Does the bracket need to be certified by the panel Mfg or a building standard ?

peakbagger

There is a fine line between height of the panel off the roof from a wind uplift basis versus an air flow viewpoint. I believe that at least a few of the rackless framing systems require side skirts to prevent air flow from the sides of the panels due to wind uplift and remember when sizing my Iron Ridge racked system that I was limited on the roof spacing. If I went over a certain point the selection would be invalid as I would exceed the uplift rating.

Generally roofs in high winds fail by wind uplift. What normally happens is a section of the roof on the upwind side is pulled up free of the structure and then wind enters the interior space and zips off the rest of the roof. With solar panels, the gap is already in place so the vertical lift is the limiting factor. If I were to redo my system, I would probably put an extra set of roof brackets on the upwind side of my panels directly at the edge of the panels to cut down on cantilevered upwards load on the brackets that are spaced evenly along the racking.  The problem is that the racking company has little control over how well the roof brackets are attached to the rafters and how well the underlying roof is secured from wind uplift. Most stick built northern roofs are built to deal with snow load (compression) where nailing is fine but nailed structures are fairly notorious for having poor wind uplift unless strapping or tie plates are used.  

Xizang

Seems to me if a criticism of 1.25 inch clearance above the roof is an airflow concern, then skirting around panels would be unthinkable.  If having 1.25 inch gap isn't enough for a good draft for cooling, then completely blocking all airflow with skirting would be the ultimate worst. 

On the other hand, if you allow too much air flow to get under the panels, the wind has leverage to pick up and peel the panels up off the roof.

Isn't the main reason why we have soffit and facia trim under our roof eves to prevent the wind from getting under the roof to peel it up off the walls?   Too much airflow can pick up a parked airplane at the airport and flip it over.  I've seen that happen.

Photowhit

Xizang said:
Isn't the main reason why we have soffit and facia trim under our roof eves to prevent the wind from getting under the roof to peel it up off the walls?  

I believe, it is to prevent trapping moisture.

Xizang

Photowhit said:

Xizang said:
Isn't the main reason why we have soffit and facia trim under our roof eves to prevent the wind from getting under the roof to peel it up off the walls?  

I believe, it is to prevent trapping moisture.

Yes, I suppose it helps keep driven snow and rain out.   Soffit and facia also works to keep out nesting birds, insects, rodents like squirrels, and down south, frogs and toads.