Tech Shield – Any Trouble with Shingle Warranties or Wifi Reception?
I thought these issues with the foil-faced (for radiant barrier) roof decking were resolved, but I heard a prominent and revered moisture and roofing consultant insist that the major composition shingle manufacturers still will not honor or issue warranties for their products installed on foil-faced roof decking. Is this true? He went on to say that there was also a problem of radio frequency interference or Wifi reception for anyone living under a foil-faced roof deck. I haven’t seen any documentation on this alleged problem. Does anyone have any experience on either or both of these issues? Thanks.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Yes, but the ETs won't be able to read your mind, either.
According to the Florida Solar Energy Center:
Will heat build up in the roof and damage my shingles?
It's extremely unlikely. The Florida Solar Energy Center has measured the temperatures of roof shingles above attic radiant barriers on hot, sunny summer days. Depending on the color of the shingles, their peak temperatures are only 2-5° F higher than the temperature of shingles under the same conditions without a radiant barrier.
Roofing materials are manufactured to withstand the high temperatures to which they are frequently exposed. A 2-5° F increase in peak temperatures that normally reach 160-190° F should have no adverse affect.
What about my shingle warranty?
Shingle warranties should not be subject to cancellation by the manufacturer on the basis of radiant barrier installation. However, it may be wise to review the warranty to be sure that work of this nature will not void it. You may want to inquire directly of the manufacturer. Any changes in warranty should be substantiated in writing.
However, the Insulation Contractors Association of America warns that an unvented roof can reduce your shingle warranty to 10 years.
There is evidence that foil-faced insulation, metal roofs and - especially - chicken wire plaster lath can interfere with or prevent WIFI or cell phone signals. The chicken wire, common in Edwardian San Franciso homes, creates a Faraday Cage which is the perfect spacing to completely block 2.4 gHz WIFI signals.
Thanks, Robert. And yes, I've also heard that issue regarding shingle warranty reduction during a recent EEBA conference. I think a lot of that is due to the ICAA's concern with the urethane foams gaining ground in the insulation biz, but in the meantime, I've read the OwensCorning composition shingle Warranty and Installation instructions this morning with neither document mentioning denial or reduction of warranty due to foil-backed decking or unvented attic installations. George Bice of Pacific Supply was kind enough to send me a quick e-mail reply flatly stating that, "Shingles applied over TechShield will NOT void the warranties," (his emphasis). Thanks for your response, Robert (both of them). In the meantime, I'll keep the tinfoil hat close by and look deeper into that shingle warranty reduction scare over an unvented attic.
You will not experience any damage to your roof. I have had TechShield for a good bit of time now and roof is in great shape. However, you will have to get a cell phone booster due to to the tech shield knocking out all signals. My Wifi still works exceptionally well however, as long as you don't have any techshield in the walls.