Attaching Solar to 12" SIP Panels

michael_34

Hi,



Has anyone attached solar racking to a SIPS roof? The roof covering is asphalt shingles. This is for PV not solar thermal. I called the manufacture, searched the web and I have not found out much. Any input welcome.

Thanks,

Michael

Larry Weingarten

Yes

Hello:  I've done exactly this.  The SIPS panels I was working on were four feet wide with truss joists between them.  I used 1" floor flanges and set two lags into the joists.  From there came up with 1" galvanized pipe and put a roof jack around each one.  If you have greater spans or no joists, it becomes a different story.



Yours,  Larry

michael_34

No joists

Hi Larry,



There is no joists in these SIPS. It would of made it a Whole Lot Easier!

Thanks for the response.

Michael

Fortunat

sheathing

I don't love to do it, but if you are installing on an existing SIP roof and there is no opportunity to get blocking inside the panels, it is possible to install a PV system into only sheathing.



Obviously it depends on the wind and snow load in your area as well as that particulars of the install, but in most cases you can achieve adequate fastening to sheathing alone. It isn't my favorite thing to do, but you can do it safely.  I can't remember the exact manufacturer, but in these cases we use a mounting foot which takes about a half dozen fasteners each, rather than a single lag, thus further spreading the load around to more fasteners.



A #12 wood screw with 1/2 inch engagement in C-D grade plywood has a 315 lb ultimate pullout strength. Do the math to figure out the maximum uplift generated by your array (paying particular attention to the array corners) and the specify at least 4-6x that much fastener (to account for the variation in plywood).



If you know the manufacturer of the SIPS, start with them as pullout strength varies for various types and thicknesses of plywood.



~Fortunat

www.revisionenergy.com

hot_rod

Evac tube

some of the evac tube installations are supposedly "adequate" into just sheathing with multiple fasteners. Try the folks at Zillarac they seem to have unique mounting solutions often with engineering data to back them up.



hr

hot_rod

Evac tube

some of the evac tube installations are supposedly "adequate" into just sheathing with multiple fasteners. Try the folks at Zillarac they seem to have unique mounting solutions often with engineering data to back them up.



hr

Zman

4'

If the SIP's are spanning a long distance they are often reinforced with microlam's. The reinforcement would be at 4' centers and sandwiched between the panels running along the long side. Measure 4' from the top or bottom and see if you find one. Even if the micro is not there the plywood should be doubled. Always use a large diameter fastener and find the perfect size predrill to get the best hold on ply and osb.

Carl

michael_34

Screwed

I ended up drilling extra holes in the L-feet so each one had 4 screw per. It felt very strong and was recommended by the builder.



On the West side of the array I attached to the top plate on which the SIPS set. Then I attached to two glue lams with 14'' screws.



It was hard to obtain direct info from the company or reps on this subject. Thanks for the input.

Michael

ABSolar

Another method

I used this method on my own house to attach a pair of 4' x 8' flat plates flush to the roof.  The roof is sips panels w/ osb for the top side, covered by tarpaper and asphalt shingles.  I used the largest diameter butterfly toggle bolt assemblies that I found at the orange box store - I think the bolt diameter was 7/16".  Since the mounting is flush, I thought the sandwiching effect of a toggle bolt was sufficient for wind lateral shear and vertical withdrawal.  I just made sure the hole I drilled to pass the toggle through was the absolute minimum size (I think it was 3/4' or 7/8").  I live on a big hill that sees some big wind in the winter, the setup has held since I installed back in 2008.  My alternative method would be to spread the load out with many screw fasteners to distribute the load over a wide ( 10" x 10" minimum) foot base.

AB