Waterproof mounting solution.

[shaniac]

Greetings, I am about to install two heleodyne hot water panels on my neighbor's roof. The panels are about 48" on center along with his rafters. We were looking at using the http://quickrackpv.com/ lag bolt water tight system for attaching the flush mount kit to his roof, but i wanted to get the groups opinion first.

1. Has anyone used these? Your thoughts?
   
2. What else have you been using that works for decades?
   
   

I have never drilled through a roof before where someone actually was living below. I would love your input.

Thanks so much!

- Shane

[w9kh]

I haven't put any pv systems on a roof (or anywhere else for that matter).  I have mounted a few antenna tripods to roofs.  All we would do to waterproof it was fill the hole with caulk when the bolt was just about all the way through, then caulk over and around it.  Roofing tar would work just as well.  

What is the cost of those mounting brackets?  I don't know how many of those fabricated mounts you would need to use, I would imagine quite a few to disperse the weight.  I have always been a fan of solid mounting.

My .02.

If you use them, I would be interested to know how well they work.

Kevin

[SteveCH]

I haven't used those, but I did mount my first rack of PVs on my roof over 20 yr. ago. I used lag bolts into the joists, silicone sealant around them. It worked fine, but ten yr. later I decided to reroof the house to go to metal after a lot of fires around here [cedar shingles originally]. Removing the pv rack was a royal pain, and I moved them permanently to the hillside behind my house so I'd never be faced with that again. However, that will be your neighbor's problem someday and not yours.... Anyhow, regular good-brand silicone worked for me, at least for the ten yr. or so they were up there. [I had angle iron bolted to the roof, the legs of the pv rack bolted then to the angle iron, silicone in the bolt holes and around them for a couple inches...no leaks.] There is a newer stuff called Through the Roof that I've just begun trying. They claim it sticks to anything roofwise. But I am not recommending it...yet. When I say "they claim," I mean the mftr., and I have no reports from any users.

[ghurd]

I never used them.

Personally, I do not care for the idea of lag bolting through the shingles to the primary trusses.

If a leak develops in the bolt hole it will not show until a substantial amount of strength or structural damage is already done.

I set the assembly so the holes will be between the trusses, drill the holes, add 2x4s or 2x6s between the trusses to match the holes, fill the holes with silicone, place the assembly/bolts/washers/etc with a good amount of silicone between each of them, then through bolt the entire mess, then smooth the silicone somewhat like a roof.

Then I make a pile of silicone in an inverted `V' higher on the shingles to route the rain water around each bolt hole.

My ideas probably don't match up with code.

Never had a leak that I was made aware of.  Knock on wood.

Just my 2 cents.

G-

[DanG]

Where is the install and do you have access to the inside attic areas beneath the panel mounts & what is the roof composition? Spreading out the area is a good thing, as well as using roof slope and gravity to stop water wicking identical to shingle design. That is a neat system and I know one home owner who wishes they'd had it, though it would have required twenty-eight(!) of them in addition to the QD brackets.

I just removed this system from a local house, the roof was asphalt shingles and over twelve years the weight and HEAT on the 3"x5" foot-print of the panels' flush mounting brackets had welded shingle layers down to deform the roof line and created valleys around them that worked to collect water. In hotter climates I see the extra rail system might help keep through-roof mount systems cooler so they'd weather better.

I'd sure go with a slow-cure solvent-based polyurethane sealant instead of silicone, Trempro 636 is very slow, meaning highest ratio of solids to solvent so very little shrink and has very little silica texture in it to better seal metal to any surface. I've seen metal layers interior sealant of that still pliant after 40 years. Good stuff.

The far left set of panels had been installed with Silicone and although the sealant was still there and not shrank or degraded in itself, it HAD lost its bond to both the metal and the shingles, simply held in place by 1/100th its original bond. Those brackets came away with only the top shingles surface granules attached to the caulk. The other panels were all done with a butyl rubber sealant that suffered some cracking and could have used refreshing every five years but otherwise showed nearly perfect sealing - and had to be cut out with both layers of shingles from beneath them.

[TheCasualTraveler]

     That mount looks fine although my guess would be it's pricey. The important part is that you follow the instructions as far as placing and sealing the mount. Do that and you can use anything. I used simple 2" x 2" aluminum angle brackets. I lift a shingle tab, position the bracket with one face under the shingle tab, drill a small hole into the rafter of truss, make a little bed of roof tar and place the bracket into the tar, screw it down with a stainless screw, more tar on top, and lay the shingle tab back down. Whatever you do you want to seal the hole properly and direct water over and around the mount. You can see the idea by reading the directions in that link. Easy to do right but a lot of folks do it wrong also.

[LarryDalooza]

I am surprised not to see any mention of flashing. I would set up some flashing to channel water away from running right over the bolt intrusion.

Lar.

[imsmooth]

My panels were put on a year and a half ago and the roof is perfect.  The installer drilled a small circle out of the shingle over the rafter.  A pylon was inserted and secured with lag bolts.  The base was sealed with roof tar/silicon.  An aluminum boot/flashing was placed around the pylon.  The upper end was inserted under the shingles, and roofing tar was inserted around the base.  No water has gotten in despite several heavy storms.  If you want the manufacturer let me know and I will see if I can find it.

[w9kh]

This is basically how I have mounted a few antenna tripods I have been involved in.  Besides a 2x4 or 2x6 between the trusses, you can build them up and then run one across several trusses to disperse the load.  I wouldn't go into the trusses directly either.

Kevin

[KeepItSimpleStupid]

A mount that has the potential to be very good, is actually the same as used for plumbing fitting.  Use the same type of aluminum/rubber flashing to put a post through the roof.  Thesse have lasted many years without leaks.

A tapped pipe cap could provide the top connection.  A stud might even be better.

The bottom could be just as easy.  Some Unistrut and a pipe clamp.

Reroffing, when required just uses existing techniques for the penetrations.