- Why rail-less?
It makes good sense to use the frame of the PV module for both structural and electrical bonding. It translates into less resources, less money and less time to install.
- Can RT-[E] Mount besides the rafters also be installed on the roof decking?
Yes, the Stamped PE Reports (Professional Engineering) documentation lists the performed tests (shear, pull-out and compression load testing). It details many configurations according to the site specifics and it has been prepared for a direct install on the roof decking. Testing was performed on 7/16” OSB (24/16 APA), 15/32” Plywood (32/16 APA) and 2”X 4”, 24”o.c. rafters. The reports are available based on the ASCE 7-05 (2006 and 2009 IBC and IRC codes) and the ASCE 7-10 (IBC, IRC 2012 codes). The PE Reports can be downloaded at http://roof-tech.us/support/ All you need is to cross reference it against the requirements from your local AHJ (Authority Having Jurisdiction).
- What is butyl tape?
Butyl is a copolymer of isobutylene with isoprene and it is widely used. One of its main applications are inner tubes, asphalt roofing related products and flexible flashing for the building industry. It offers superior flexibility, it’s impermeable to moisture and it’s resistant to mildew, acids alkalis and salts. RT Butyl (Roof Tech’s own butyl tape) has a temperature range between minus 40 to 248 degrees Fahrenheit and it has been co-developed by Roof Tech’s parent Company Yanegiken in Japan specifically for roofing applications. RT Butyl is compatible with asphalt and metal roofing materials. To date, there are over 400,000 PV Residences in Japan with the very same RT Butyl tape deployed for the past 20 years.
- What is the product warranty?
10 year warranty against manufacturing defects.
- And what about the Butyl tape service life?
The service life is 20 Yr. minimum.
- If we are installing RT-[E] Mount on a 30 year roof, how do we know the mounts won’t need to be re-sealed?
This is a good question for all flashing manufacturers actually. Butyl tape is far superior to any sealants commonly used with solar flashings, you can ask folks involved in the building industry. If you look closely to any flashing method in the market, you will notice that after all, it is the sealant applied to the penetration that ultimately seals it. So, I’ll answer it with a question; how long will that sealant (a.k.a. caulking) perform?
We know that it will not last long and towards its end, it will become brittle with cracks.
Notice that the upper limit service temperature of sealants is under 200F and keep in mind that the PV array can get as hot as up to 60F above the ambient temperature. We have performed 7,500 hr. accelerated aging testing of the RT Butyl and the Sealant. The result? Only RT Butyl remained flexible performing its sealant function to protect the roof underlayment and decking.
- How does the height gets adjusted to compensate for discrepancies on a roof?
We have shims that allow the adjustment of up to ¼” above the bracket.
Sometimes the installer has the ability to move the brackets around prior to fastening them to select the roof surfaces that are in most common height.
- What is the main advantage of using the RT-[E] Mount™ product?
It is all-in-one PV mounting system, the one and only fully waterproof with an integrated flexible flashing that will perform to the test of time. Secondly, it’s fastened to the roof (not lagged), minimizing the impact to the roof penetrations due to the forces of thermal contraction and expansion of the array (roof torsion) since each panel is fastened down with multiple screws providing a perfect balance of the pressures applied through the bases onto the roof surface. A basic design technique to maintain the longer integrity of the array and the roof penetrations sealability. Being that 5 mm (3/16”) stainless wood screws are used to secure the mounts to the rafters, there is a minimum risk to split the rafter and the contractor finds it easier to comply with code based on the NDS (National Design Specification for Wood Construction). A 5/16” Lag bolt for instance, need to have a pilot hole and the correct positioning of the lag bolt on top of the rafter (parallel to the grain) is very narrow, the mid third which is about 9/16” in length. It becomes very difficult for the installer to locate it from the top of the roof. This same area becomes 60% longer with the use of 5mm in diameter screws, making it much easier for the contractor to have a code compliant PV Installation.
- What type of certifications are available? www.roof-tech.us
-ICC (International Code Council) ESR 3575 Evaluation Report for water Resistance and Durability & Compliance with IBC and IRC 2012, 2009 and 2006 Codes.
-Stamped PE reports for 28 States (IBC 2012, 2009 and 2006 and IRC 2012, 2009 and 2006 codes)
- What PV Modules are listed under the UL 2703?
As far as electrical bonding, any PV Modules with C shape or Square shape frames between 31 and 50 mm heights that are either anodized or anodized and coated. The mechanical analysis is provide on the PE Report.
As far as Fire Class Resistance Rating: Class A, any Type 1 PV Module for Steep Slope and Low Slope Roofs.
- How can I install power electronics such as a micro inverter?
The RT-[E] Mount Air offers a 3” clearance which is enough for most micro inverters and optimizers. Please double check it with the specifications of the product you intend to install.
- If we have fewer parts and all included, the pricing should be attractive right?
Correct. Not only it’s less expensive than conventional racking, it also saves the installer on freight costs. Installers have reported labor savings as high as 60% www.roof-tech.us
- Is Roof Tech’s flashing method code compliant?
Yes. It is fully Code Compliant with the IBC (International Building Code) and IRC (International Residential Code) codes. It is the only certified, fully waterproofed method of flashing.
Roof Tech is the First and only, to provide a Proven and Certified Mounting System for the Installation of LEAK PROOF PV Systems on pitched roofs tested under water.
- How about adding a metal flashing to it?
We would never recommend it! RT-[E] Mount is a PROVEN method as is.
Notice that Roofing Manufacturers have a specific warranty language as far as the “Failure to Seal” which can relate to the sliding of a sheet metal piece between the shingles as the original bonding of the shingles is disrupted.
We have conducted Wind Driven Rain Testing to verify the built up of moisture between the roof asphalt surface and the bottom of the flange. Moisture will reach to the penetration through capillarity and condensation.
We can point out to the fact that the removal of nails to accommodate the metal flange could be a code violation because by code, shingles must be installed with a minimum amount of nails depending on the local code. In a retrofit it is almost impossible to find out how the roofer installed the roof.
To top it off, the removal of nails now means the creation of a hole in the roofing paper/felt which is a path for moisture to move to the roof decking. This will be specially detrimental under an ice dam.
The NRCA does not recommend the friction of a metal plate against a membrane roofing (Low Slope) because it can cause fatigue of the membrane and eventually tears and cracks. Roof Tech treat the asphalt shingles (on a steep Slope Roof) just like a membrane roofing. Keep in mind that NRCA’s recommendation of a metal flashing to asphalt shingle roofs is with the intent of being a WATERSHEDDING flashing (Pipe Flashing) and it applies ONLY to NEW roofing installation as their recommendation clearly states and shows the underlayment lapped over the flashing flange or in other words, the upper section of the metal flange must be placed underneath the roofing paper (visit the NRCA guidelines to get the picture). It’s just common knowledge that such method cannot be applied to a PV Installation retrofit on an existing roof.
The roofing paper is considered a second layer of protection, however being that is the first layer applied, it also serves as the ultimate protection layer, for that reason, the installer of a solar PV system must NOT damage the roofing paper.
Roof Tech’s (100%) WATERPROOF mounting system becomes “One with the Roof”. Please also look for the Owens Corning letter of Warranty on the support page.
For additional information, documentation or a webinar request:
www.roof-tech.us - TEL (415) 295-7840 – firstname.lastname@example.org