What I'm Seeing Now


This Much Missing Insulation Can Influence A Whole Room

This much missing insulation can influence a whole room.

It doesn't seem like a lot, but with insulation just a little that is missing goes a long way toward dramatically increasing energy bills.

This subject house was advertised to have had a new roof installed just a few years ago.

It was an older townhouse, and going into the attic space it was obvious that much of the sheathing had to be replaced along with the shingles.

That likely was the result of the roof shingles being very old at the time of replacement.

The previous roof may have leaked substantially, rotting the roof sheathing below.

It may have also had the older, bad Fire Retardant Treated plywood.  I could see evidence of the older roof materials laying about.

But in the corner there was an area where the insulation was missing completely.

Perhaps it had been removed to get it out of the way when the roof was replaced, who knows.

It isn't a large area, but large enough to influence the room on hot and cold days.

The temperature outdoors at the time of this inspection was about 55F, not very cold or  warm.

But the sun was out, and look at how high the temperature was in the bedroom's drywall on that cool day - 86F!

This is what the missing insulation looks like from inside the bedroom as described by a thermal camera.  This would technically be referred to as a "thermal defect."  The room would also be graded by Energy Star and RESNET as "uninsulated" because it represents more than 5% of the ceiling space.

Studies have shown, and I have written before (click here), that only 5% of missing insulation can reduce the R-value, or resistance value, of insulation by 50%!  That is significant! 

RESNET and HERS rating systems define the grading of insulation in these terms:  Grade I is the best, where "insulation is installed according to manufacturer's instructions and completely fills cavities..."; Grade II is not bad, with some areas of missing or poorly-placed insulation and "moderate to frequent insulation gaps..."; Grade III as poorly insulated "with substantial gaps and voids."  And with a 5% void an area "is treated as uninsulated."  You can read the study here.

My recommendation:  have your insulation checked!  I do a thermal image sweep of the house on every home inspection, looking importantly for insulation defects.  There are many things thermal cameras can find, but thermal defects are a big part of any thermal imaging investigation.  Having a look around with a thermal camera can be very revealing.



Jay Markanich Real Estate Inspections, LLC  

Based in Bristow, serving all of Northern Virginia.

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


Comment balloon 8 commentsJay Markanich • March 21 2017 08:45AM


I woder how they could have missed an ara that large.  I  can see where you could have a cold spot in the room.

Posted by William Feela, Realtor, Whispering Pines Realty 651-674-5999 No. (WHISPERING PINES REALTY) over 3 years ago

I recently dealt with a similar issue in two rental properties where insulation was missing in spots and it had poor ventilation. That was not a good mix with our winter weather!

Posted by Nathan Gesner, Broker / Property Manager (American West Realty and Management) over 3 years ago

I see that sort of thing often... too often! Unfortunately, even in new construction homes. Get your potential dream home inspected folks!!

Posted by Fred Hernden, CMI, Albuquerque area Master Inspector (Superior Home Inspections - Greater Albuquerque Area) over 3 years ago

Those are some substantial #'s for a little bit of missing insulation. 

Posted by Lyn Sims, Schaumburg Real Estate (RE/MAX Suburban) over 3 years ago

Had a townhouse back in the 90's with FRT plywood.  Had to replace the entire roof even though it was only 12 years old.  Tried to form a regional group called Families Against Retardant Treatment.  Not sure why that name never caught on?

Posted by Stephen Weakley (Nationwide Mortgage Services) over 3 years ago

William - that area will influence the room summer and winter.

Nathan - that is the worst mix!  But hopefully an easy repair.

Fred - builders hate it when I point out missing insulation on a new construction inspection!  One said that home inspectors should not be allowed to use thermal cameras.

It really is Lyn.  The studies are getting better and better and conducted by universities like South Dakota State and Montana State.  They know cold.

I cannot believe that did not catch on, Stephen!  But it's all lost to distant memory by now...

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) over 3 years ago

Make sure that the insulation is checked by a relible contractor...here that can be as big a scam as foundation work that is "over done'"with excavation.

Posted by Sally K. & David L. Hanson, WI Real Estate Agents - Luxury - Divorce (EXP Realty 414-525-0563) over 3 years ago

S&D - there are scams everywhere!  It is amazing.  Insulation can be permanently good or permanently bad.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) over 3 years ago

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