Reuben's Home Inspection Blog


Unsealed Tech Tubes: A Common New Construction Attic Defect

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


Comment balloon 10 commentsReuben Saltzman • March 27 2012 02:56AM


Hi Reuben, thanks for sharing and the warm spot where the frost is melted tells it all!

Posted by Bob Miller, The Ocala Dream Team (Keller Williams Cornerstone Realty) almost 7 years ago

Good catch....warm roofs are a sign that some detective work is in order...sounds like housing is moooving right along in Minnesota !

Posted by Sally K. & David L. Hanson, WI Realtors - Luxury - Divorce (EXP Realty 414-525-0563) almost 7 years ago

Your posts are always educational, helpful. You put a lot of time in to them! Thanks! 

Posted by Andrew Mooers | 207.532.6573, Northern Maine Real Estate-Aroostook County Broker (MOOERS REALTY) almost 7 years ago

Bob - we call it 'nature's IR camera' :)

Sally & David - definitely!  I hope things are similar for you guys in Wisconsin.

Andrew - thank you!

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) almost 7 years ago

We see those chases all the time!  And when they are filled with cables and wires they are harder to seal, but not impossible!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 7 years ago

Reuben, this is a good post about this chase pipes---very common out here---usually from crawl space to attic.

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) almost 7 years ago

It is a great way to get future wiring into the house.  But you are right about the air way.  Even a small amount will mess things up.

Posted by Vern Eaton, Realtor 651-674-7449 almost 7 years ago

What a trained eye sees. Frosty roofs do tell stories, don't they.

Posted by James Quarello, Connecticut Home Inspector (JRV Home Inspection Services, LLC) almost 7 years ago

Jay - it just takes a little more take at that point :)

Charles - Every house deserves a data tube.

Vern - and it's such an easy fix.

James - I love 'em :)

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) almost 7 years ago

Reuben, Hey at least they were thinking ahead to put a conduit in. Just missed that one little detail. It really is amazing how much air can pass from one little ol tube.

Posted by Donald Hester, NCW Home Inspections, LLC (NCW Home Inspections, LLC) almost 7 years ago