Reuben's Home Inspection Blog


My Beef With Fiberglass Batts

Reuben's BeefFiberglass batts are a poor choice of insulation for most applications, yet this still seems to be the insulation of choice for most handy homeowners.  I'm been complaining about fiberglass batts for a while now, and for good reason.

Fiberglass batts are more expensive.  I stopped by the Maple Grove Home Depot and compared the prices of unfaced fiberglass batts, loose fill fiberglass, and cellulose.  Here's what I found:

$0.93 / square foot for R38 Fiberglass Batts

$0.56 / square foot for R38 Loose Fill Fiberglass

$0.30 / square foot for R38 Cellulose

Price Tag at Home DepotSide note:   Comparing prices at Home Depot was a pain in the butt.  Are they doing this on purpose?  The sign on the fiberglass batts said "That's only $0.93 sq. ft."   Yes, for R38... perfect.  But then the sign on a bag of loose fill fiberglass says "That's only $0.51 sq. ft."  FOR WHAT?  You have to get out a calculator and do a little math to figure out this is for R30.  What really drove me nuts was the sign for a bag of cellulose insulation, which said "That's only $0.15 sq. ft."  Again, FOR WHAT?  I got out my calculator, and determined that they're quoting the price for R19.  How are consumers supposed to make any reasonable comparisons when the three different prices per square foot are for three different depths?  These signs are worse than useless, they're misleading.

Fiberglass batts take more time to install. To be installed properly, fiberglass batts need to be painstakingly cut to fit the exact size of the space that they're supposed to fill.  Here are a few examples:

  • A 2x6 wall that has electrical wire running perpendicular to the studs;  should you push the insulation in front of or behind the wire, leaving a void in the insulation?  No.  You would need to cut the batt so it gets installed above and below the wire.
  • A 2x6 wall with electrical outlet boxes; should you stuff the insulation around it, leaving nasty gaps around the box?  No.  You would need to cut out a rectangle in the batt so it fits around the outlet box without being compressed, and you would need to install a thin piece of fiberglass behind the outlet box.
  • An attic with a bazillion electrical boxes, wires, pipes, truss chords, etc...; should you stuff the insulation around all of these obstructions, significantly reducing the insulation value?  No.  You would need to make a bazillion cuts and fits in the fiberglass batts to fill all of the gaps and voids.

The alternative to making all of these cuts and fits is to use something that fills in every little gap and void, such as loose fill fiberglass or cellulose in the attic, dense pack cellulose in walls, and spray foam at rim joists.  These methods take far less time.

Fiberglass batts are extremely difficult to install properly. As you read through the examples above, you were probably wondering who would ever take the time to actually do all of these things.  My experience has told me no one.I can't say fiberglass batts are impossible to install properly... but I have yet to find fiberglass batts installed properly in an attic.  All of the little voids that are left in fiberglass insulation equate to an exponential level of heat loss.  The photos below came from a five-year-old custom built home in Edina that I did a home inspection at.

Poorly installed fiberglass batts Poorly installed fiberglass batts 2

Poorly installed fiberglass batts 3 Poorly installed fiberglass batts 4

Fiberglass batts are itchy. I can touch the stuff with my hands and I'm fine, but once that stuff gets on my forearms, it's bad news.  My skin gets red, bumpy, and itchy.  Even if you're just walking on it, the fibers gets released in to the air and they float for a long time.  You're skin doesn't even need to make direct contact with it to be affected.  This makes fiberglass nasty stuff to work with or be around.

So why are fiberglass batts still used today? For small jobs, such as re-insulating a wall or two, it might not make sense to hire an insulation contractor to fill the walls with dense pack cellulose, and it's not cheap to have spray foam installed.  As for attics, again, there is no special equipment needed to install fiberglass batts.  To blow loose fill fiberglass or cellulose, a huge insulation blower and hoses are needed, so it turns in to a fairly big project.  It's far easier to buy a few rolls of insulation at the store, drive 'em home in your car, and roll them out in the attic.

If you have an upcoming insulation project, I suggest using something other than fiberglass batts.  In the near future, I'll write a blog discussing all of the alternatives to fiberglass batts.

Reuben Saltzman, Structure Tech Home Inspections


Comment balloon 66 commentsReuben Saltzman • March 22 2011 06:27AM


Hi Rueben, I had a post similar to this one last year. And we are both right. Cellulose is the way to go.

Have a great day, Clint McKie

Posted by Clint Mckie, Desert Sun Home, Comm. Inspection 1-575-706-5586 (Desert Sun Home, commercial Inspections) about 8 years ago

"It's far easier to buy a few rolls of insulation at the store, drive 'em home in your car, and roll them out in the attic."

Asked and answered.

Posted by Lenn Harley, Real Estate Broker - Virginia & Maryland (Lenn Harley,, MD & VA Homes and Real Estate) about 8 years ago

Great post, Reuben.  I recently had my house insulated and they used dense pack cellulose.  But when I "do it myself" in a rental property, I use batts.  Why?  because I didn't know loose pack fiberglas was available at the HD, and because I wouldn't have been able to figure out how to make it stay in an open wall installation.

I'll look forward to a future discussion.

Posted by Ann Bellamy (Hard money lending for investors in NH and MA) about 8 years ago

I like blown in insulation much better than batts.

Posted by Steve Traylor, ASHI Certified Home Inspector (A+ Home Inspections dba A+ Services, LLC) about 8 years ago

Clint - hey, could send me the link to that post?   I'd love to read it.  I agree, cellulose gets the most bang for your buck.  Foam is best... but man, that stuff is expensive.

Lenn - I can understand the small projects.  What shocks me is when entire attics get insulated with fiberglass batts.

Ann - Home Depot will actually let you use their insulation blower for free if you buy enough loose-fill fiberglass or cellulose insulation.  At least they used to, I haven't checked recently.  

Steve - me too.  

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

Good Morning Reuben, excellent input on batts.  (They are very itchy!)

Posted by Dan Edward Phillips, Humboldt and Del Norte Counties, CA (Dan Edward Phillips, Humboldt and Del Norte Counties, CA) about 8 years ago

Hi Reuben - Really good explanation of why fiberglass batts are a poor choice - but an easy one. This is a well-deserved Featured post!

Posted by Judy Klem, Home Staging, Senior Move Management, Fairfield/New Haven counties (Transition Stage LLC) about 8 years ago

Dan - Thanks.  To add insult to injury, they're not just itchy, but they're also a lung irritant.  I can't be around fiberglass without a mask.

Judy - thanks.  I'll have a good upcoming discussion of the alternatives, hopefully within the next month.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago


Many DIY projects fall far short of required standards. Thanks for educating us on fiberglass batts.

Posted by Irene Kennedy Realtor® in Northwestern NJ (Weichert) about 8 years ago

Hey Reubs.  Good stuff, and agreed from my end.

When I finished a part of my basement to turn it into a TV/billiard room, I put the plastic-wrapped, "itch free," fiberglass (R-13) in the ceiling as a sound block.  While it's worked really well, and was fairly easy to install (I did it by myself), it was NOT itch free!

That is one of the few good uses of fiberglass!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 8 years ago

There is a good article in Fine Home Building March 2011 about insulation in walls. They state the new found best way is to spray foam and then put fiberglass over it. You save some money using the fiberglass but solve it's inadequacies with the spray foam.

Posted by Rob Ernst, Reno, NV-775-410-4286 Inspector & Energy Auditor (Certified Structure Inspector) about 8 years ago

Sometimes the easy choice is not the correct is EASY.

Posted by Dennis Duvernay Broker/Owner (Hillview Realty) about 8 years ago

Reuben, the fiberglass batts are the easy way out. I used them when I finished off my lower lever and itched for a week. Thanks for the info.

Posted by Michael Setunsky, Your Commercial Real Estate Link to Northern VA about 8 years ago

Fiberglass is such an interesting element. I've had the same allergic reactions that you mention above. It's not pleasant.

Posted by Aaron Seekford, Ranked Top 1% Nationwide 703-836-6116 (Arlington Realty, Inc.) about 8 years ago

brings back nightmares of my low man on the totem pole construction job...a.k.a. fiberglass boy.  thanks for the post.

Posted by Kevin Kueneke, San Diego Mortgage Banker (Caliber Home Loans) about 8 years ago

Good points, interesting to compare spray foam as an oprion as well.u

Posted by Derrick Buckspan about 8 years ago

You are so right about the voids where the insulation is no up snug to a floor joist, wall stuff. All those little cracks add up to a large hole in your home costing more money and your wallet to open wide, say ahhhhhh!

Posted by Andrew Mooers | 207.532.6573, Northern Maine Real Estate-Aroostook County Broker (MOOERS REALTY) about 8 years ago


Never really gave much thought to it, but that was an excellent summary.


Posted by Brian Madigan, LL.B., Broker (RE/MAX West Realty Inc., Brokerage (Toronto)) about 8 years ago

i echo Kevin, I'm itching just thinking about those days! Thanks for the info!

Posted by Chris and Berna Sloan, Tooele UT (Group 1 Real Estate) about 8 years ago

Reuben, thanks for the clarification between the batts and the rolls. Rolls sounds much better.

Posted by Gary Woltal, Assoc. Broker Realtor SFR Dallas Ft. Worth (Keller Williams Realty) about 8 years ago

Reuben I couldn't agree more.  For dozens of reasons fiberglass insulation in batt form should be the LAST choice as an insulation material---I don't even like calling it "insulation."

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 8 years ago

Well, consumers are always ready for a trade-off. In order for fiberglass batts to perform exactly as they should they need to be cut precisely. If consumers just want to get 80-90% performance out of their insulation, they will just jam 'em in there. Perfection is not always the goal, just a littlle lower bill for a little effort.

Posted by Robert Slick, NRBA, RDCPro, Trident/CCAR MLS (Beach and River Homes) about 8 years ago

Fiberglass is one component of a vapour barrier and insulation system that should be professionally installed.

It is widely used here as it is effective both from costing and function points of view.

It is glass. The 'itching' is from a thousand micro cuts, thats all. No allergies are involved, period. That is a medical fact. The human body will break down and eliminate any ingested or inhaled glass with no ill effects other than irritating short term discomfort.

The micro cuts heal within a few days, but you this does not mean no protection is required. Especially a face mask.

So hire a pro to do it right and all the 'Issues' will disappear.

The home centres are in business to sell to you. That doesn't mean you should buy.

Posted by Robert Butler, Montreal Home Inspector | Aspect Inspection (Aspect Inspection) about 8 years ago

Irene - I agree, a lot of DIY projects fall short.  In the case of fiberglass batts, I think it's even more than just the DIYers.  Pros seem to screw this stuff up left and right as well.

Jay - the plastic wrapped stuff wasn't even itch free?  Bad news.  What are you paying for then?

Robert - I'm a huge fan of spray foam.  Love that stuff.

Dennis - and if the path of least resistance is your goal, go for it.  Many homeowners seem to thing that fiberglass batts are the superior to any other type of insulation.

Michael - my dad recently had fiberglass batts removed from his own attic, and the guy who did the work said he itched for a week!  Nasty, nasty stuff.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

Aaron - I didn't mention it in my blog, but I spent a lot of time working around fiberglass insulation and other construction debris growing up, and I developed an allergy to it.  If I'm around fiberglass insulation that becomes airborne, my eyes will start watering, my nose starts running like a faucet, and I start sneezing non-stop.  This will go on for several hours.  Bad times.  Any time I go in to an attic, I wear the full respirator.

Kevin - I used to be that person too.  I would also be the person who did all the demo.

Derrick - I'm sure I'll have much more to say about foam in the near future.

Andrew - Those voids have an exponential effect.  

Brian - thanks!


Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

Chris - I started feeling itchy just looking at the photos.

Gary - you mean 'blow-in' sounds much better, right?

Charles - what's really crazy is finding it installed in an attic by a 'professional'.  WHY?

Robert S - I would so much rather blow the insulation in...

Robert B - even when fiberglass is 'professionally' installed, I find it's usually done wrong.  I'm quite certain that my body has developed an allergy to fiberglass; I get so ridiculously sneezy after being exposed to airborne fiberglass that I'm basically useless.  This only lasts a few hours, but it's no fun.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

Thanks for your words of wisdom and experience!

Posted by Sharon Parisi, Dallas Homes (United Real Estate Dallas ) about 8 years ago

I saw some green fiberglass on Holmes Homes...I don't see that our here in San Diego...maybe it's seen more on the east coast.

Posted by Cory Barbee, Broker (760) 563-4022 about 8 years ago

Not a fan of open faced fiberglass or single faced fiberglass insulation.  I push for the bio-base foam insulation when at all possible as it is healthier and more energy efficient.

Posted by Barb Van Stensel about 8 years ago

Hi Reuben, that pink panther has done a great marketing job.  Good post, thanks.

Posted by Dale Ganfield about 8 years ago

The 'dirt' on fibreglass, medically speaking, is founded on solid medical research here in Montreal (Magil University Medicine). So it is scientifically established fact.

But of course it will still feel like allergy symptoms and we can all agree it's no fun. If I skip wearing a mask in attics with fiberglass I know it for hours after.

Posted by Robert Butler, Montreal Home Inspector | Aspect Inspection (Aspect Inspection) about 8 years ago

Hi! Reuben,

Foam insulation might be more expensive, however in the long run you will save money using the foam. I let a contractor convince me to use fiberglass batts in a new construction home in lieu of foam. I built another almost identical hoem with the foam. They both sat vacant for a while before they sold. A/C units were identical and set on the same temperature. My electrical bill for the home with batts was more than forty dollars per month more than the home with foam.

Properly installed foam and cellouse along with other energy efficient construction methods could easily reduce energy use by 70% or more. How about an 1800 square foot home with energy bills less than $100 per month.

Posted by Bobby Dean about 8 years ago

I do thermal infrared evaluations of missing and missinstalled insulation.  Most would be amazed at how badly it is installed in most cases.  "Out of sight, out of mind" I guess. 

If the batts or any other insulation are not in direct contact with the back side of the wall board, it is not installed properly. It should in many cases have a vapor barrier facing the room side. If not, the moisture from the interior will work its way into the cooler spaces and condense, saturating the insulation and creating a potential a mold problem.

Insulating properly is best left to the pros and the quality of their work should be verified by a thermal performance scan.

Dana Bostick

Posted by Dana Bostick (True Professionals, Inc.) about 8 years ago

"because, that's the way my dad did it" LOL

Reality is spray foam is probably the best choice, expands and seals the house tight... But it is harder to do, and probably costs more up front...

Posted by Robert Rauf (HomeBridge Financial Services (NJ)) about 8 years ago

Spray foam insulation is the best and has been independently scientifically proven in building models to be the most energy efficent insulation for residential construction for insulation purposes. A high R value, no off gases, easy to apply and fills all gaps.

Dave Brice CHI

Posted by Dave Brice CHI about 8 years ago

we just installed fiberglass batts in our garage and you are SO right! What a pain

Posted by Sandy McAlpine, Search Lake Norman Homes For Sale - Lake Norman NC (RE/MAX EXECUTIVE) about 8 years ago

So the foam is most effective for insulating and avoiding any leakage of air into and out of the insulated strucuture. Is there any support to the rumor that a structure that is very tightly insulated so that it is lacking in air flow in/out (windows and doors closed of course) contributes to poor health because the oxygen gets depleted by human occupancy and flame-based heating systems? The rumor continues making the point that the stagnant air leads to trapping of pollutants (radon, CO2, chemical gases from furnishings, etc.) which contributes to health issues.

Any comments or input appreciated. Thank you.

Posted by George Walsh about 8 years ago

Hi Reuben

I agree totally with your take on fiberglass batts.

As you mentioned foam is expensive but is the only insulation that effectively stops air infiltration, which is the major cause of comfort issues (i.e. cold drafty floors) in the home. Cellulose will not stop air movement but fills the stud cavities far better than batts.

Owens Corning has a new product that is marketed as being a lower cost option to foam but a better insulator than cellulose. It is called Energy Complete which is a two part insulation system comprising of spraying a liquid latex based sealant along the joints, cracks, and penetrations from plumbing and electrical installations and then blowing in fiberglass wool to fill the cavities. For complete information look here:

Posted by David Ward (Sweet Home Chicago Inspector LLC) about 8 years ago

If air movement is not controlled before insulation is installed it does little good. I'm not a big fan of batts for an attic either. Blown cellulose is heavier and has some air sealing qualities. I have rated many insulation jobs that when the voids and missing spots are tallied, the R-38 goes to about R-20. Cellulose has to be done right too. It has to be consistent in depth and not tapered back from the eaves. The pull down attic stairs is another bad spot. A batt glued to the back disappears when you point an infared camera at it! Seal first...then insulate!

Posted by Andrew Herren (Craig Massee Real Estate) about 8 years ago


You need a blower door test don on your home to determine how many air changes per hour that you have before sealing. The new building code call for 7 ACH50 wich translates to about .35 natural air changes per hour. I still firmy believe that you should continue to seal and add air back to your home either through a dampered port on your HVAC or an ERV. If you stop sealing because you are too tight this means that your air is still potentially comes from musty or over/under heated parts of your home. Sorry for some of the bad spelling in this post, it wont let me go back and edit!

Posted by Andrew Herren (Craig Massee Real Estate) about 8 years ago

Very informative and useful information, thanks for sharing.

Posted by Kimo Jarrett, Pro Lifestyle Solutions (WikiWiki Realty) about 8 years ago

Thanks Reuben for the information ! I agree with a lot of what you say about Fiberglass . However , all types of insulation have their good points & bad .

I've been using Johns Mansville Formaldehyde Free F/G insulation for years with good results , when installed properly . Our average Energy Star Home with Fiberglass Batt has a HERS Rating of 56 which is 44% better than a code built home . We also install a 2nd layer of F/G in the attic perpendicular to the first layer which overlaps the ceiling joists or truss chords or spray loose fill F/G over the Attic Batt ! If not installed properly , F/G can be just a filter to the exterior ! How do you recommend insulating a home in the winter , so you can provide temporary heat so you can install the drywall without at least a nominal amount of F/G Batt in the ceiling ?

Dense Pack Cellulose is good , if there is not too much moisture trapped in the wall cavity after insulation & prior to drywall , which can lead to mold & mildew . The density is critical to avoid settling which can leave voids & a good installer is critical . It is usually installed in attics after the drywall , so it creates some logistical headaches in colder climates in winter time .

Johns Mansville Spider Spray-in F/G is a great choice for wall cavities as it completely fills the cavity leaving no voids , but is more expensive than most other alternatives.

Loose fill F/G in the attic , works good down to about 20 degrees Fahrenheit , then a convection loop can potentially form , so it can loose some of its effectiveness .

Open Cell foam work great , as long as it doesn't absorb moisture , which can turn it into a sponge . Closed cell foam is much better & acts as a true barrier , but it is also much more expensive than the aforementioned alternatives . Foam is a nasty thing for the applicators to install .. just ask one . There can also be a fire danger , if it is installed in too thick a layer in one shot , so the application is again critical . There is also some market perception concerns about off gasing left over from the Urea Formaldehyde days . I've only used foam , in limited applications , as our past clients chose not to spend the additional $ on foaming the whole house .

Thanks for bringing properly installed F/G & other alternatives to everyone's attention . Keepin' it Green !


Posted by Edward D. Nikles (Ed Nikles Custom Builder , Inc. / Nikles Realty , Inc.) about 8 years ago

Great post  and a well chosen subject.  I love foam myself but it is so expensive it's ridiculous. I think it's a case of. "Let's charge a lot because we can."

Posted by Marshall Brown, BSEE, CHI (Mid America Inspection Services, LLC) about 8 years ago
Hi Reuben I would not have known this, but thanks to your post I would not now make this mistake thanks for sharing. I will say this about the spray in foam 30 years of Welding taught me this stuff is extremely flammable and gives off very toxic fumes I would be reluctant to put it in were I was going to live. ...........Brad
Posted by Brad Hornshaw, Realtor, Listing Agent, Buyers Agent, Investments (Brad Hornshaw Realtor Lynnwood, Bothell, Everett) about 8 years ago

Hi Reuben,  I am a fan of "blown in bats" where a taught netting is stapled to the wall before a high density cellulose is blown in.  A 2" x 6" wall can have a prescriptive R value of 21.   The wall is completly packed with insulation, avoiding the voids often found with a fiberglass instillation.    Jim O   former contractor. 

Jim Olney Realtor since 1991 
DIRECT 206.234.5641 FAX 206.666.3373 

Rockwell Realty
Connected to Community

Posted by Jim Olney, Seattle Broker since 1991 (Rockwell Realty LLC) about 8 years ago

I like the rigid insulation. Works well for temp but also seems to work better than fiberglass for noise too. I don't know how it would compare with cellulose so I await your next blog with baited breath!

Posted by Pete Buckley (Independent Broker/Realtor, North San Diego County CA.) about 8 years ago

I'm looking forward to your follow up. I've seen many poor installations of fiberglass bats.

Posted by Dennis & Terri Neal, Your Home Sold in 45 Days or We Se (RE/MAX, Big Bear) about 8 years ago

Rueben - Great information! I'll be tweeting/facebooking your blog out today.

Posted by SentriLock Blogger (SentriLock, LLC) about 8 years ago

Thanks for the post!  I hate fiberglass, but don't want to spend for the other .....  Maybe it would pay for itself if I did, though...

Posted by Dagny Eason, Fairfield County CT, CDPE Homes For Sale and Condo (Dagny's Real Estate) about 8 years ago

Great post.  These are the kinds of articles I like to see at Active Rain.  A lot of retails are playing games wiht pricing - I am finding it harder to compare prices at the supermarket.

Posted by Gene Riemenschneider, Turning Houses into Homes (Home Point Real Estate) about 8 years ago

Cellulose not installed correctly settles and leaves voids at the top.  Have used cellulose.  After it had been installie we had an electrical issue.  When we pulled the paneling there was about a 14 inch void at the ceiling.

Posted by Robert Courtney, Century 21 All Islands, RA, CDPE, MCRE, CIAS about 8 years ago

congrats on the feature, great job!

Its a dirty job....

Posted by Jayson Hoffer, Mesa AZ 480-948-6115 Home, Auto, Life Insurance (Jayson Hoffer Insurance Agency Inc.) about 8 years ago

I love that Daily Drop :)   Thank you for reading, everyone!  

Dale - I think the pink panther is a good part of the reason that homeowners are so sure that fiberglass batts are the gold standard for attics.

Robert - can't your body develop allergies to anything?

Bobby - I totally agree with you about foam.

Dana - I started doing infrared scans this year, and I've found the same thing.  Batts are never installed properly.

George - you ask if a tight house can cause health problems?   Absolutely.  We now need to depend on mechanical ventilation to control air exchanges in the home.  This is where HRVs enter the picture.

David - Energy Complete looks like an option in-between air sealing with canned foam and full foam jobs; maybe we should call this the 'silver standard'.  This looks like a nice option.

Andrew - I'm huge on sealing attic air leaks (aka - attic bypasses).  I've seen so many attics with so much air leakage in the past few months that I've recommend complete removal of the existing insulation in many cases.  

In your note to George you mention an ERV; for anyone else not familiar with the terms, an ERV (Energy Recovery Ventilator) is similar to an HRV (Heat Recovery Ventilator), but it will also help to control moisture during the summer.  HRVs don't do this.


Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

Ed - you wrote "How do you recommend insulating a home in the winter , so you can provide temporary heat so you can install the drywall without at least a nominal amount of F/G Batt in the ceiling ?"  I must be missing something here... because you can't.  The drywall needs to be installed before the insulation is installed.  How else could you seal up all of your attic bypasses?

That was a good discussion of the different types of insulation for different spaces.  I'd like to comment on all of them, but I'm also in the middle of writing a long blog discussing these different types of insulation.

For the record, the study conducted in 1991 showing that loose fill fiberglass is only good down to 20 degrees doesn't apply today.  Stay tuned, I'll have some good info on that.

I guess things might be different in your area, but here in Minnesota, I've found that the prices of closed cell and open cell foam insulation are pretty much identical. 

Thanks for reading, and thanks for the comments :)

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

Marshall - Interesting thought on foam, "let's charge a lot because we can."  I'll be sure to research that theory and get back to you on it.

Brad - I'll try to address the flame spread requirements of foam insulation when I write about it.

Jim O - I'm a fan of those blown-in batts too.  Good stuff.

Pete - I like the rigid stuff too.

Dagny - I'll have a follow up or two with alternatives to fibeglass.

Robert - A 14" void is bad news and shouldn't have happened.  I'd call that a bad installation (not a bad product).

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

The comments are just as interesting as the post. I of course agree with 125%. One other poor quality of fiberglass batts no one brought up was their thickness.

2 x 6 walls are actually 5.5 inches in depth. When a R-19 fiberglass batt, which is 6.25 inches thick, is putt into that wall cavity it is compressed by 3/4 of an inch. Which reduces the R value! That's a little detail that seems to escape discussion.

Another thing I would mention to all the spray foam advocates is that the stuff is highly flammable. I am mystified how it passes the fire rating.

Posted by James Quarello, Connecticut Home Inspector (JRV Home Inspection Services, LLC) about 8 years ago

James - I've gotta think the manufacturers of fiberglass batts make the batts just a little thicker on purpose and take that compression in to consideration when calculating the R-value, don't you?  I don't know that for a fact though.

As for the flammability thing... what I think you're saying is "Reuben, will you please take a blowtorch to a chunk of foam insulation and post a video in your next blog?"  No prob, James. 

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

Reuben, The thickness has been an issue for years. They don't make it thicker to compensate for compression. In fact compressing fiberglass most certainly degrades the R value.

As for the foam insulation, there was a horrific fire in a night club out this way in 2003. Over 100 people killed. The fire spread very quickly and was in part blamed on foam insulation. This raw video is very disturbing, but you can see what happens when this stuff catches fire.

Posted by James Quarello, Connecticut Home Inspector (JRV Home Inspection Services, LLC) about 8 years ago

James - so why the heck don't they make the stuff 5 1/2" thick?

Also, we watched that video during a college course on commercial building plans inspections.  The focus was on not taking shortcuts and not permitting any changes to emergency egress.  You're right, that was a very disturbing video.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

Btw, I don't think the stuff that caught fire in that video is the same stuff that gets used in houses for insulation.  

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

Reuben, I've seen a video of an independent testing lab conducting fire testing on insulation. Foam insulation burns fast and with lots of thick black smoke just like in that video. as good as everyone says that stuff is, I would never put it in my house.

Posted by James Quarello, Connecticut Home Inspector (JRV Home Inspection Services, LLC) about 8 years ago

How old was the video?  I know it burns fast and gives off thick black smoke (which contains cyanide)... but maybe the newer generation of foams are formulated differently?  I don't know, just postulating.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

I really don't know, but I can't believe anything has changed, except maybe the price.

Posted by James Quarello, Connecticut Home Inspector (JRV Home Inspection Services, LLC) about 8 years ago

Go Cellulose!!!!

Posted by David Evans, HUD NLB Cumming GA (RE/MAX TOWN AND COUNTRY) about 8 years ago

I sprayed two attics last fall with the blow in fiberglass stuff from Home Depot and it's not itchy at all. It's a different product that the fiberglass batts.

Posted by Wayne B. Pruner, Tigard Oregon Homes for Sale, Realtor, GRI (Oregon First) about 8 years ago

Tigard - I've heard the newer stuff isn't as bad.  No itch at all?  Nice.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago