Solar roofing material

Jack

on a solar system for the house. DHW for sure and looking into a PV system also. While I have instaled many solar system and worked on more roofs, I would not install my system without first doing a re-roof. Mine is a pretty much standard low pitch colonial roof in New England, which I would "over-collector" as necessary to compensate for the pitch. The house is a a two story with a walk out basement, so effectively three stories. This south pitch cannot be seen from the ground as the property slopes also so appearanace of the material is not a consideration.

My question is, What type of roofing material do you like to work on. Cost is certainly a factor, but durability (you do have to clean panels) and ease of drainage are important also.

hot_rod

for flat and low pitch

I've been researching and watching TPO. Here is a link that explains a bit about it

www.buildings.com/articles/detail.aspx?contentID=3498

I have been taking Roofing Contractor magazine for a year now, trying to get a feel for the contractors takes as far as pros and cons of this material.

We did a Habitat home last summer with a white TPO roof. I liked the look, feel, and ease of sealing penetrations.

I have metal rib roof on my shop and office. Too low of a pitch for metal, I'm getting bids to insulate over the metal, with foam sheets that match the metal profile to level it out, then install a TPO over the whole thing.

Seems it takes 20 or 30 years of actual installations before we know for sure how these products hold up.

hr

mark schofield

some thoughts

I built my Cape in 1977 with standard 30 year shingles. Then installed two solar panels in 1980. I had to re roof a few years ago which meant, for me, to remove the panels and frame so I could shingle under where they were. The roof pitch is 45 deg so the panels were basically flat on the roof on a 6" frame. Had I known 30 years ago, I might have tried to roof under the panels with something longer lasting so I wouldn't have had to remove them. The house faces south so the northern side (with a dormer) has a different exposure and thus different weathering characteristics. It could have gone another 6-7 years. For the difference in price over the years, I'd go with something that will at least outlast the panels. Mark S.

hot_rod

Flashed in collector

here is a prototype of a product we showed recently at the HomeBuilders Show.

It's a one piece, heavy gauge aluminum flashing (curb) kit for a collector. The flashing goes on the roof and is shingled in. Then the panel, with rear connection attaches to the "curb". The whole package ends up looking like a skylight.

The panel is removable and replaceable, a new roof could be installed at any time, and all the piping and wiring is hidden. You would need access under the roof, of course, to install this package.

hr

scott markle_2

is that the picture you were meaning to post?

I like this idea of surface or curb mounting a collector. No exposed pipe work is another plus. I believe Velux the skylight company is getting into the solar thermal market. Unfortunately the literature available on there web sight was geared to consumers and did not provide much real information.I also believe the Buderus collectors can be set into the roof, although all the pictures of this showed flashing to european tile roofing.

This sort of set in design is probably only suitable for single collectors, I would not want to depend on a gasket between the collectors.

I like standing seam roofs, there is a nice mechanical connector known as the S5 that clamps to various standing seam profiles and provides penetration free anchorage.

rene_4

Hot Rod, Have you read my response to you I sent yesterday in the question forum titled Solar install and lightning protection? Thanks.

Rene

Rich L.

Velux Solar

I've spoke with a Velux solar rep about their solar panels. I really like the fact that the penetrations are on the bottom, under the unit. Once the unit is flashed in to the roof you don't have to worry about roofing replacement or roof penetrations for your piping. Unfortunately these panels are only going to be available to "factory approved and trained" installers. I understand that they want to protect their reputation but I feel they will severly limit their market share as well. I assume anybody can go to the lumberyard and buy their skylights without qualification.

hot_rod

I'v heard those S5 clips

don't pass code for thermal panel attachments, At least in that is what the California installers tell me. Most fasteners have to pass SRCC or FEC testing for wind loads, etc. Have you heard that?

hr

Metro Man

flashed solar panels

It has been out experience that although flashing solar panels for aesthetics looks great it is not always the best way to go especially if the flashing is an integral part of sealing the roof. Most solar panels are not designed as a 100% sealed and water can (and will) find a way to leak in. Once that happens you now have water in the solar collector frame and if the roof is not sealed or worse stopped by the back side of that flashing you could have water in the house. The flatter the roof the worse you will be off. Consider this when you have a collector array on a 3/12 pitch, 2 feet of snow, and things start melting.

Here in lies the problem with a flush mounted solar system. If the collectors use back legs or stand off then the entire system can be mounted on curbs and roof can be accessed or worked on at any time.

With multiple solar collectors you have the problem with sealing in between the collectors which is not an easy thing to do.

I prefer flush mounted systems because of the way they look. What I would do is get with the roofer and look for ways to prep the underside of collector array so house could be re-roofed without removing solar collectors. Maybe ice/water shield then shingles or a modified roof or ??? Or just put a 40 + year shingle, flash for looks and don't worry. This is what we do.

My 2c

Metro Man