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New Construction - And A Double-Pane Glass Bull's Eye

New Construction - and a double-pane glass bull's eye. 

I have had double-pane glass bull's eye blogs before, but never one with sliding glass doors.

Seals break on double-pane glass, doors and windows.  Theoretically the seals can break at any time - due to age, or after severe deflection caused by high winds, or during installation when the window or door is mistreated or improperly installed.

When a seal breaks on double-pane glass it is not immediately evident with sweaty condensation or cloudiness. It's invisible to the naked eye.

Whether the interior cavity is filled with gas or air, negative pressure is created when the vacuum-sealed interior leaks and dissipates and the two panes are pulled together.

As they get closer the cooler air outdoors is manifest where the panes are the closest.

At the time of this image the outdoor temperature was about 55F.  The indoor temperature was about 70F.  The resulting bull's eye is quite apparent.  You can see the balcony, it's railing, and the building beyond.

Had it been colder outside the bull's eye pattern would be even more pronounced.  But it is quite clear.  There was no condensation or cloudiness in the glass.  The door is very new.  The left side is fine, the right side had the beginnings of a broken seal.

The only way to detect broken seals in double-pane glass of any age, but particularly with new products, is with a thermal camera.  Eventually this would have demonstrated droplets of condensation and then cloudiness that would get worse with time.   This room is an upper-level room with a large wall with a TV jack and plenty of space to sit or go out onto the balcony and relax outdoors.  A cloudy sliding glass door would be a big spoiler!

My recommendation:  even new construction needs inspections.  And a thermal camera can detect many things from poorly-placed insulation, to unsuspected leaks, to electrical and mechanical issues, to even bull's eyes in glass!  Mighty Mo, my thermal camera is the sharpest arrow in my home inspection tool quiver.  Find an inspector with some thermal imaging skill and a good camera and hit the home inspection bull's eye...



Jay Markanich Real Estate Inspections, LLC  

Based in Bristow, serving all of Northern Virginia.

Office (703) 330-6388   Cell (703) 585-7560


Comment balloon 14 commentsJay Markanich • October 29 2016 03:32AM
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