The Best Way To Insulate An Attic

Unfortunately, the easiest way to add insulation to just about any place in your home is to install fiberglass batts.  Fiberglass batts are typically the worst insulation for any job, as I complained about in a recent blog.  I mentioned at that time that I would follow up with a blog about the other choices of insulation.  Today I’m going to discuss several different types of attic insulation.

The best way to insulate an attic or pretty much anything else in a home is to use spray foam insulation. There are two types of spray foam insulation; open cell and closed cell. I’ve also heard people call them ‘half pound’ and ‘two pound’ foams, respectively.  Open cell foam has an insulation value of up to R-3.9 / inch, while closed cell has an insulation value of up to R-6.9 / inch.  Closed cell foam will act as a vapor barrier when installed to a depth of at least 2″, while open cell foam won’t act like a vapor barrier at any depth.  For an in-depth discussion of the differences between closed cell and open cell foam, click here open cell vs closed cell foam.

When properly installed, either type of spray foam insulation will act as a perfect air barrier, sealing off all attic bypasses.  Spray foam insulation will also completely eliminate convection; air cannot move through foam insulation.   The downside to using foam insulation is the expense; foam costs way more money than anything else, and it’s definitely not a do-it-yourself product.

I’ve heard some people complain about the flammability of foam insulation; yes, it’s flammable, but it will typically be completely covered in the attic.  The fact that it’s flammable wouldn’t stop me from installing it.  If you’re curious, here’s a quick “don’t try this at home” video.

I’m such a firm believer in spray foam insulation that I had this done at my previous home, which was a one-and-one-half-story house.  For this style of house, foam is definitely the way to go; the insulation gets applied directly to the roof decking, and it’s called a hot roof.  The foam gets completely covered with drywall after that.  For traditional roofs, I’ve made up my own set of standards.

The Gold Standard

For a traditional attic, there is no need to use foam throughout the entire space, as you’ll get the most value out of the first couple inches.  A cost effective way to use foam insulation is to foam the lid of the house, then use loose fill insulation on top.  This means installing spray foam to a depth of at least 2″ on the entire attic floor to completely seal everything up.  After the foam is cured, loose fill fiberglass or cellulose insulation gets installed on top of the foam.  Because fiberglass costs more, has a lower insulation value per inch and makes my skin itch, my preference would be cellulose.

If it’s an older home with only a few inches of space between the tops of the outer walls and the roof, you won’t have much room for insulation here; extra spray foam needs to be installed here to help compensate for this.

Here in Minnesota, the minimum allowable insulation value for a new construction home is R-38 for an attic, but federal standards suggest R-50 for our climate.

Oh, and one other cool thing about spraying closed cell foam on the attic floor is that once the foam cures, you’ll be able to walk on the entire attic floor; not just the truss or floor joists.  I’ve done it.  It’s crazy.  That closed cell foam is strong stuff.

The Silver Standard

Prep the attic before insulation.  Have every attic bypass completely sealed.  Foam in a can is great stuff for most smaller attic bypasses (didja see what I did there?), but watch out for gas vents; they require a 1″ clearance.  Have insulated boxes constructed for any recessed lights – they contribute a ton of heat to the attic.  If it’s an older home where the rafters or trusses only leave a few inches for insulation at the outer walls, you won’t have enough room for proper insulation at the edges; hire someone to spray foam these areas with closed cell foam to get the highest insulation value possible.  Of course, don’t forget to install baffles at the eaves to prevent your soffit vents from getting blocked.

After everything has been prepped, it’s time to insulate.  My preference is cellulose insulation.  If you do it yourself, you can buy the insulation in bags from your local home improvement store, and they’ll probably let you rent an insulation blower for free.  The DIY cellulose insulation method is very dusty, but it’ll get the job done.  If you hire a pro, they’ll use wet-spray cellulose, which adds a small amount of water to the cellulose to help control the dust and to slightly increase the insulation value per inch.

If you choose to use loose fill fiberglass instead, don’t worry; it’s not bad stuff.  There was a widely publicized study conducted by Oak Ridge Laboratories in 1991 that said that loose fill fiberglass insulation lost a lot of its insulation value once temperatures dropped below 20 degrees, making loose fill fiberglass an inferior product when compared to cellulose.  I contacted Andre Omer Desjarlais at Oak Ridge Laboratories about this issue, and he said “This was true 20 years ago but all fiberglass manufacturers have changed their products appreciably since then and this is simply no longer an issue.”  I also contacted several insulation manufacturers about this, and they said the same thing and sent me some great information, which I posted on my web site; click any of these links to read the documents from Certainteed, Johns Manville, or Owens Corning.  Loose fill insulation will still experience convection, but not nearly as much as old fiberglass used to.

The Bronze Standard

Just use cellulose insulation in the attic.  Cellulose does a good job of controlling condensation in the attic and it’s a fairly dense product, so it will cut down on air movement from attic bypasses, but won’t completely eliminate them.

The Brown Standard

Roll out a bunch of fiberglass batts, proudly proclaim “done and done”, and have yourself a cold one.

Oh, and as for the attic access panels or pulldown attic steps?  I’ll cover those in another blog.

Reuben Saltzman, Structure Tech Home Inspections - Email - Edina Home Inspections

    

My Beef With Fiberglass Batts

Fiberglass 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

Side 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.
 
 


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 - Email - Edina Home Inspections
    

The Dirt On Expensive Furnace Filters

Are super expensive furnace filters really worth the extra money?

The main job of a furnace filter is to keep big stuff from getting in to the furnace’s heat exchanger or the air conditioner’s air coil and clogging things up with dust, pet hair, and other big stuff.  They’re not intended to purify the air you breathe.  Furnace filters protect equipment; not people.

Manufacturers of furnace filters would have you believe otherwise (big surprise).  The most expensive disposable filters that I commonly see are the Best 1″ Air Filters made by 3M. These filters are marketed as being able to

“help attract and capture allergens from the air passing through the filter including mold spores, pollen, pet dander, dust, smoke, smog particles and particles that carry bacteria and viruses.”

Sure.  I’ll buy that.  I’m sure these filters do a great job of preventing all those things from passing through the filter. There is no claim made, even by 3M, to improve indoor air quality.  Up until recently, these filters were sold as “Ultra Allergen” filters, but they’ve recently changed their wording.  I don’t know when this change happened, but I’m sure it was quite recent – you can still purchase “Ultra Allergen” filters on Amazon.

If you want to improve indoor air quality, try something else.Expensive furnace filters have been proven to have a very small effect on indoor air quality.  There is plenty of anecdotalevidence out there that says expensive filters will solve all of your indoor air quality problems, but I haven’t been able to find a single study backing these claims.

The problem with expensive furnace filters is the amount of air flow that gets restricted when they get dirty.  As I mentioned in my blog about the importance of changing your furnace filter, reduced air flow can actually lead to premature failure of your furnace, besides costing you more in heating bills.  This can also lead to service calls on your furnace.  Furnaces come equipped with heat sensors that will shut the furnace down if the heat exchanger gets too hot, and the main cause of this is insufficient air flow.

At my own house, I use a cheap pleated filter.  It’s reinforced with steel wire on one side and will last for up to 90 days.  I have a German Shepherd (Stanley) who sheds like crazy, so I change my filter a little more often – about once every 60 days.  I don’t like the super-cheap fiberglass filters because they seem to let too much stuff through, and I’m concerned that the air coil would get gunked up with all that dust that would still come through.

My recommendation is to skip those super-expensive furnace filters.  I think they’re a waste of money.

Reuben Saltzman, Structure Tech Home Inspections - Email - Maple Grove Home Inspections

    

The Whipped Up Home Inspector

When I used to work in retail, I remember dealing with rude, crabby, demanding, and downright ridiculous customers.  It got frustrating at times, and it would usually happen on a daily basis, but it was pretty easy to just leave that stuff at work.  Once I'd punch out, whatever happened at work would quickly become a fading memory.  My work didn't define me; it was just work.

As a home inspector, it's completely different.  I never punch out.  My occupation and my sense of self have become tightly intertwined.  When I write an inspection report, I make an effort to word everything just right; I know it sounds tacky, but my report becomes a little extension of myself.

When someone questions my report or says I'm wrong, I can't help but take it personally.

As the home inspector, I typically don't ever hear about what happens after my inspections.  The negotiations after the home inspection are really none of my business, but I do like getting feedback.

<cue happy music>  
 The seller is going to replace the 40-year-old boiler?  Awesome!  
The seller is going to replace the leaking roof?  That's fantastic. 
The seller is taking $3000 off the price of the house so you can get a new furnace?  Sweet.   Spend a little extra and get a high efficiency model.  
The seller won't fix the furnace venting.   That's too bad.   
The seller won't fix the furnace venting because they said it's not a problem. 
<Insert sound effect of a record needle scratching, music stops>

Ok, that last one gets my attention.  While I realize that the seller is just defending their own home, I take this personally.  I can't help but hearing "the seller said you're wrong."  The most common version of this that I hear is that the installation was already inspected by the city, the installation passed the city inspection, the installation meets the city code, or some version of that.

If a seller won't fix something, great.  It's none of my business.   When a seller tells a buyer they won't fix something because it meets code, I take it personally.  While a home inspection is not a code inspection, if I say something was installed wrong, I'm also saying that the installation doesn't meet code.  When a seller says the installation meets code, they're saying I'm wrong, and the integrity of my report comes in to question.

I received a call from a home buyer the other day with just such a situation, where the seller said they wouldn't fix the furnace venting because it met the city's code.  Sorry, wrong, no.  If the city approved the installation, it means they didn't catch any problems with the installation.  It doesn't mean the installation was done right, or even that it meets code.
 
For most requests about information, I tell people I'll send 'em an email as soon as I get home or as soon as I get in front of a computer.  I was driving to an inspection when I received this particular phone call.  I pulled in to a parking lot, got on my laptop, and quickly sent the buyer and the buyer's agent an email defending my stance - it included a link to my blog titled "...But The City Approved It!".  I knew I wouldn't be able to concentrate on much else until I did.

If you want to get a home inspector whipped up, just tell 'em the seller won't fix something because it passed the city inspection.

Reuben Saltzman, Structure Tech Home Inspections - Email - Minnesota Home Inspections
                    

Invasive Moisture Testing on Stucco, Revisited

I recently wrote a blog about invasive testing vs infrared scanning on stucco homes, and concluded that invasive moisture testing is the only reliable test method for stucco homes.  I received quite a bit of feedback on ActiveRain, and even had another home inspector in San Diego, Russel Ray, write a follow-up post titled Invasive “testing”?  Are you kidding?, wherein he opines that invasive moisture testing is outdated.

Today I’m going to explain why invasive moisture testing is not outdated, as it’s the only reliable option in Minnesota, and I’m also going to discuss the differences between interior and exterior moisture testing.  But not in that order.

To gather information about this blog, I spoke with moisture testing experts from four of the larger stucco testing firms in the Twin Cities: Barry Eliason of Private Eye Home Inspections & Moisture Testing, Wayne Shellabarger of Acuity Engineers, Inc., Alan Powell of Certified Moisture Testing, and one other expert who wished to remain anonymous.  I asked them about their preferred testing methods, and asked them to explain why.  All four can provide both interior and exterior testing.

Interior vs. Exterior – The Basics

Exterior testing of stucco is done by drilling holes in the stucco at suspect locations, sticking a moisture probe in to the wall, and measuring the moisture content of the wood or wall sheathing with a special moisture testing device, such as a Delmhorst Moisture Meter.  Interior testing is done by drilling holes in the interior walls, and then sticking a long moisture probe through the wall to the exterior wall sheathing to take a moisture reading.  These are both reliable testing methods.

Interior vs. Exterior – Cosmetic Issues

Whether holes are drilled in walls from the exterior or interior, the walls won’t look exactly the same when the work is done.  I’ve inspected many stucco homes that have had invasive moisture testing done, and in every case the holes were quite inconspicuous.  The person drilling holes in stucco will come equipped with a wide range of sealants to fill the holes when they’re done, and the resulting 1/4″ holes are barely noticeable once filled with with matching caulk.  For interior testing, the holes aren’t as easy to hide or patch.  If holes are drilled in drywall, they’ll obviously need to be patched and painted over again.

Cosmetically, exterior testing is certainly preferred, as you really need to walk around the exterior of the house and carefully look for the test locations; they’re not obvious.

Interior vs. Exterior – Holes In The Stucco

One concern with drilling holes in stucco is that this will compromise the drainage plane behind the wall, and the caulking used to fill the holes won’t get far enough in to the wall to seal the drainage plane again.

Wayne Shellabarger, who is opposed to exterior testing, said that he has found holes in the drainage planes that were never properly sealed up after invasive testing was performed.  I asked him if there was water damage caused by the breaks in these drainage planes; the answer was no, but he was also quick to mention that in the cases he has seen, the holes were only a year or two old.

Alan Powell said that while the holes they drill in stucco are 1/4″ holes, they don’t drill through the drainage plane behind the stucco.  The only thing that penetrates the drainage plane behind the stucco are the pin probes on the moisture testing device, which leaves 1/8″ holes.  When you think about all of the holes that get created in the drainage plane with staples and whatever else, the holes made by the pin probes will be quite insignificant.

After over a decade of invasive testing and having tested thousands of homes, none of the companies that perform exterior testing have had a single reported problem with this testing method.

Interior vs. Exterior – Accessibility

The biggest problem that Barry Eliason expressed about interior testing is that there are oftentimes interior wall surfaces that make testing impossible in some locations.  There are several places where holes can’t be drilled, such as through bath tubs, shower walls, tiled walls, and cabinets just to name a few.  Alan Powell also expressed concerns about being able to test in the proper places on interior walls; windows usually leak in the corners, and to properly test the right areas, the wall sheathing directly behind the walls studs is the most critical area to test.  This area can’t be accessed from the interior walls.

On the other hand, Wayne Shellabarger said that if a home has moisture problems, there will still be enough accessible areas for him to find problems, even if he can’t find every one.

Infrared, revisited

Some home inspectors say they’ve had good luck using infrared cameras to find moisture behind stucco walls, but I say they don’t know what they’re missing.  I think everyone can agree that invasive moisture testing is accurate; if a tester drills holes and sticks moisture probes in the wall, they’ll be able to locate moisture if it’s there.  To know if an infrared camera can reliably detect moisture in walls, one would need to scan a house with an infrared camera and then compare those results to an invasive moisture test.  If an infrared camera could reliably find wet areas behind stucco, it would be useful.

I have yet to hear from a single home inspector, anywhere in the country, who has performed infrared scans on houses, compared those results to an invasive moisture test performed at the same time, and can still claim that infrared scans on stucco houses are reliable.

All four testing companies that I interviewed said the same thing about infrared inspections on stucco homes: they’re unreliable.  Each company shared the exact same experience with me.  They were excited when infrared cameras came on to the market, they purchased infrared cameras, they went through extensive training on the use of IR cameras, and then they began using IR cameras on houses before performing invasive testing.  They all say that IR cameras are a completely unreliable way of finding moisture behind stucco.  Wayne Shellabarger’s web site says they use infrared cameras as a starting point before performing invasive testing, but he told me they no longer even offer that service because it has proven to be a waste of time.

Non-Invasive Moisture Meters (aka – surface scanners)

Russell Ray mentioned in his blog that he has had a 100% success rate testing for moisture on stucco homes in California using a surface scanner, such as a Tramex Moisture Encounter Plus.  This device is a fairly inexpensive non-invasive moisture detection device that, according to the manufacturer, can be used on “drywall, wood, plaster, brick, ceramic, porcelain tiles, resilient flooring, laminates, asphalt composition shingles and most building materials.”  Stucco isn’t listed.

I called the manufacturer to ask about using this device on stucco (I spoke with Penny).  She said that if the stucco has metal lath, it won’t work.  This is the same with all non-invasive surface scanners.  If the scanner is used from the interior, it also won’t work, because it won’t read nearly deep enough in to the wall to reach the exterior wall sheathing, which is the part that needs to be tested.

When Russell or anyone else has a 100% success rate using a surface scanner on stucco, that means they’re not using it on the same type of stucco that we have Minnesota.   Stucco homes in Minnesota have metal lath.  Surface scanners will have a 0% success rate on this material.  To echo Russell’s point, regional differences are huge.

Conclusion

Here in Minnesota, performing an invasive test on stucco is the only way to know what’s happening behind the stucco on a newer stucco home.  Problems can’t be positively identified using visual inspections, surface scanners, or infrared cameras.  Visual inspections will often provide clues that a problem exists, and so will infrared scans, but that’s all they can do.  Many times, stucco homes will have serious problems without any visual or infrared evidence.

As for the interior vs. exterior testing debate, they both have their pros and cons.  If you’re buying a newer stucco home in Minnesota, have an invasive moisture test performed.  You’ll need to hire a company that specializes in this, such as one of the companies that I listed at the beginning of this blog.

Oh, and of course, you’ll need to get special permission from the seller to do this.  Drilling holes in walls is invasive; home inspections aren’t.

Reuben Saltzman, Structure Tech Home Inspections - Email - Infrared Home Inspections