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cutieme 03-08-2010 07:54 AM

Installing solar panels and need new roof
I live in NY and need to get new roof before they install the solar panels. Here are my questions:

1) Is GAF Shinglemate better than a 30 lb felt for underlayment? What's the difference in price?

2) Would you recommend ice and water shield to be put in place of the felt or fiberglass where the solar panels will be laid down which would only be 30% of the roof? If not, why?

3) Would installing standoffs (which would be installed prior to putting the underlayment and shingles and will be screwed onto the rafters) for the solar panel mounting better than the regular mounts which get installed after the roof is done, therefore, making holes on the shingles and the roof itself?

4) Should the roofer install 1 or 2 layers of ice and water shield? What's
the code in NY?

5) How much should a new roof cost, we have a ranch and an up and over roof and no valleys and approx 2200 sq ft. I am looking to get a 50 year either Tamko or GAF Timberline Architectural Shingles. We have one skylight on the roof.

6) How would I know if what they will be placing on my roof is a 50 yr and not the 30 year?

Thank you so much for any information you can provide.

xxPaulCPxx 05-02-2010 12:33 PM

I'm surprised you got no answer!

I'm looking into addding solar PV/Water at a later date, but will be reroofing soon. I had similar questions, and here is what I found:

1. I'm a fan of the Synthetic underlayments, like RoofTopGuard and Titanium UDF (I used the latter a couple years ago on a garage reroof). They have to be installed according to directions though. 1 roll covers 10 squares, and one person can easily handle that roll onto the roof. 1 roll costs about $140.

2. I&WS should be anywhere you think you are going to get a penetration other than a nail. No reason not to do it.

3. In my research, it seems that you really can't preinstall the standoffs without knowing exactly what is needed. Plus, that spacing may change based on the system you choose. Looking at a number of companies, they all seem to use the same product, which is an aluminum sheet that goes under a course of shingle and has the stand off on top of that, underneith is filled with silicone roof patch for the 5/16 lag penetration to your rafter. If you add I&WS preemptively to the area you know will be covered, you've covered all your bases.

4. One layer should be enough for a normal pitched roof (4:12 or more), code is specific to your municipality which I would doubt would cover this.

5. Price is something specific to your area, but I bet there are alot of QUALITY roofers out there needing work at the moment.

6. GAF and other companies have front to back systems, that can be installed by factory trained roofing contractors. That is about the only way you are going to get a real true warranty on your roof. You will know what they are installing by looking at the packages they deliver and break open - they will say 50 year qualifying warranty on them, but make sure your contractor installs them to the warranty specifications AND is willing to back that warranty.

AaronB 05-02-2010 01:10 PM

Have you considered a photo voltaic roofing system instead of a roofing system and additional solar panels?

Luv2Roof 05-10-2010 03:04 PM

Since I am a roofing contractor that also installs solar systems, I'll throw in my 2 cents....
  1. Havent used Shinglemate so I cant comment on its use. In a comp shingle roof I have no problem using 30lb felt. However, I too like the synthetics and we have been using them more and more in our shingle installations. I like Titanium UDL as it does have a limited amount of self sealing ability.
  2. If I was installing both the roofing and solar I would NOT use I&WS overall unless the solar array had the potential to cause a ice damming condition. I would not do so mostly due to increased cost. I would use I&WS at the penetrations. I would use I&WS at the solar array if I wasnt installing the solar due to the risk of the solar guys damaging the roof. If it makes you sleep better at night, I would install the I&WS as its additional cost will be pretty minor compared to the solar system.
  3. If at all possible, install the standoffs concurrently with the roof system (this is one of the reasons we do both). That way the standoffs can be correctly flashed and there is no need to tear up the new roof at a later date to install the standoffs. It also helps to minimize the wear-and-tear damage the solar installation will cause to your roof. Also, standoffs are good for maintaining a larger airspace between the roof and solar system. The larger airspace allows airflow between the roof and solar panels which helps cool the solar panels which in turn improves solar performance. Solar panels DO NOT like the heat.
  4. I dont know what code is in NY as I am in CA. But we install roofs around Lake Tahoe and use only 1 layer of I&WS. I have been told by some I&WS mfg's that they do not want 2 layers of I&WS. (Not sure why this is; maybe water entrapment?)
  5. I dont know what roof prices are going for in NY.
  6. I havent used Tamko, but GAF has the year printed on their packaging. Just look at the shingle bundle wrapper and it will say whether its' 30yr., 40yr., or 50 yr.
As AaronB indicated, there are other solar options available. However, generally speaking the glass panel systems are usually the most cost-effective.

Yoyizit 05-10-2010 03:26 PM


Originally Posted by cutieme (Post 411400)
5) How much should a new roof cost,

What size solar panels?
For non-PV you could get 1kw per sq. meter 5 hrs/day, for PV maybe 15% of this.

xxPaulCPxx 05-10-2010 09:29 PM

Since you do both, is there a standard setup you would space a bracket system? Would he need a standoff every 24", 32", 36", or 48"? What about the vertical axis?

In other words, if you were going to mount the standoffs this year for an unknown system going in next year, how would you do it?

Luv2Roof 05-12-2010 05:46 PM

My comments are limited to PV solar panels and not thermal or other solar things.

The spacing of standoffs correspond to the loads the solar system places on the structure. There are both live (snow)/dead loads and uplift loads that need to be accounted for. The spacing also depends on what racking system you are using. For example, I know that you can go up to a max 72" spacing with UniRac Solarmount systems per UniRac's specs. However, that spacing may not be allowable per code or engineering requirements once the actual loads are calculated. The substrate to which you are attaching the standoffs may also only support so much of a load. You need to have an engineer review the design. They will be able to tell you what the spacing is.

Without knowing any details, I would space the standoffs no more than 48" OC and probably less since you will have more snow load than I am use to.

The vertical spacing is dictated by the layout of the array. You need to run 2 UniRac "beams" under each panel.

Jim F 05-12-2010 09:08 PM

Code in NY is 6 ft up from the edge with ice and water shield, up from 3 feet previously. On a small roof it ends up being about 2/3rds covered with I&WS anyway.

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