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A New Attic Problem with New Construction Homes

By In Attic Bypass On March 27, 2012

For about the last twenty years or so in Minnesota, it’s been standard practice to seal up attic bypassses; little passageways for conditioned household air to leak in to the attic.  Attic bypasses are also known as attic air leaks.  It’s important to seal all of the bypasses in an attic, because air leaking in to an attic has a far greater effect on attic warming and heat loss than just missing insulation.

I’ve been doing a lot of new-construction inspections or one-year warranty inspections on new construction houses, and I’ve started to notice a new attic bypass that seems to be completely ignored by some builders and insulation contractors.  At a recent new construction inspection in Woodbury, I actually had a good suspicion that I would find this defect as soon as I pulled up to the house and looked at the frost covered roof.

That dark spot on the roof shows a warm spot where the frost never accumulated.  Click on the photo for a larger version.

Attic bypass visible on frost covered roof

This localized warm spot on the roof is the result of a tube that was fed in to the attic as a chaseway for future wires, such as satellite cables or antenna cables.  The other end of this tube is located in the basement utility room, near the data cable box – they call this a data tube or a tech tube, and I think it’s a great idea.  What better way to get low voltage wires from the basement to the attic?  The only problem is that some installers seem to forget that this is another attic bypass that will leak warm air in to the attic.

Uncapped tech tube

Just as every little hole and crack that allows air in to the attic needs to be sealed off, so does this relatively large opening.  Thankfully, the fix for this situation is very simple; just cap the end of the pipe.  This can be done pretty much any way you see fit – I’ve seen it done with both electrical tape and duct tape, and it works fine.  If you have a newer home, this is just one more reason to break the seal on your attic access panel.

Data Tube

Tech Tube

Reuben Saltzman, Structure Tech Home Inspections – Email – Minnesota Home Inspector


About the Author


Reuben is a second generation home inspector with a passion for his work. He grew up remodeling homes and learning about carpentry since he was old enough to hold a hammer. Reuben has worked for Structure Tech since it was purchased by Neil in 1997, and is now co-owner of the company. Reuben’s favorite customers are the ones who have a lot of questions; he grew up thinking he was going to be a school teacher because he enjoyed teaching others so much. In a sense, that’s a lot of what home inspections are about, so Reuben truly does what he loves. Reuben has an A.A. degree in liberal arts and has attended most of the Building Inspection Technology classes at North Hennepin Community College. Reuben and his wife are the proud parents of two young childen, Cy Alexander and Lucy Nicole, and have a German Shepherd named Stanley. With two young children Reuben doesn’t have much free time, but he still tries to play disc golf as often as possible during the summer. Reuben lives in Maple Grove, MN. Professional Qualifications / Memberships: *ASHI Certified Inspector *President, ASHI Heartland Chapter *Member, Minnesota Society of Housing Inspectors (MSHI) *Licensed Minneapolis Truth-in-Sale of Housing Evaluator *Licensed Saint Paul Truth-in-Sale of Housing Evaluator *Licensed Maplewood Truth-in-Sale of Housing Evaluator *Licensed Hopkins Truth-in-Housing Evaluator *Licensed Robbinsdale Point of Sale Evaluator *Affiliate Member, Southern Twin Cities Association of Realtors

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  • doors and window repair 3 YEARS AGO

    Thank you for another great post on home inspections. That is an easy fix for that warm spot causing the attic leak. I look forward to more of your informative posts!

  • Austin Home Inspection 3 YEARS AGO

    Thank you for another great post on home inspections. That is an easy fix for that warm spot causing the attic leak. I look forward to more of your informative posts!