Ned Pelger's blog on construction, design and other weirdness. Email him at ned@constructionknowledge.net
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CONSTRUCTION KNOWLEDGE BLOG
April 23, 2011
Aluminum Foil House Wrap Kills Wi-Fi Signals
Radio signals like mobile phone, Wi-Fi and even satellite TV do a fairly good job passing through stud walls and windows to get into buildings. Over the years I’ve noticed that Pre-Engineered Buildings tend to do poorly with radio signals because the metal roof and walls reflect those radio waves rather than let them pass.
This month’s cover story for PC Pro describes how house construction materials can have a huge effect on your radio wave reception inside the walls. A simple choice of construction materials could lead to many annoying moments inside your new home or office.
The article includes this photo showing a house being constructed with a aluminum foil faced house wrap. The product appears to be Protect TF200 Thermo. From a thermal prospective, this product would be superior to Tyvek House Wrap because it would reflect some thermal radiation back into the heated space along with helping control the air leaks of infiltration. I believe that thermal advantage would be minimal, but the radio interference could be a major annoyance. I will use a Tyvek type product, or building paper, when house wrap is needed in the future.
On office buildings, we sometimes use Thermax cavity wall insulation between the concrete block and the brick. Thermax has an aluminum foil backing that would also reflect radio waves. In the future, I’ll be specifying Styrofoam for cavity wall insulation, to improve the Wi-Fi and mobile phone experience of the future users.
Admittedly I haven’t seen the science on this issue, no real test studies that I know of. But my own experience, as well as my understanding of basic physics, leads me to conclude that I want to avoid foil wraps on walls and roofs when I can. Since products exist that do a similar job at the same cost, I’m going to forgo the (what I think to be slight) thermal benefit in hopes of not messing up mobile phone and Wi-Fi reception.
By the way, if you’re in a home or office that has terrible radio wave reception and discover you have foil backed house wrap or roofing, you are probably up the proverbial creek paddle-less. Since there aren’t any simple fixes, it’s worthwhile to try to avoid the situation on future projects.
Thanks to Kneal for yet again finding items of interest. You are truly the geek’s geek. And, of course, I mean that in the best possible way.