Monthly Archives: November 2011

Insulation: Properly Installing Fiberglass Batts

The last two posts have concerned issues of properly installing Fiberglass Batt type insulation.  That discussion revolved around newly installed insulation.  Inspections were done after the insulation was there and before the drywall was installed.

In this post, I would like to address some of the problems I see after the home has been in use.  The Batts in these cases were installed anywhere from 10 years ago to 40 years ago.  We all have experienced the issues of time. What changes does time bring to a Fiberglass batt?  This leads to ‘Why proper installation is so important.”

I have audited home that were built more than 100 years ago.  My friend Bud, has discussed auditing homes that are much older, 150 – 250 years. A home lasts a long time.  Every month the home gets Energy Bills.  Are the Energy Efficient Features of the home keeping those bills at the level they were planned?  If a feature was improperly installed, probably not.

Best Practices for installing Fiberglass Batt type insulation include:

The insulation must be in contact with the Air Barrier.  In our Climate Zone the Inside wall is the Air Barrier.

This means the batts must be stapled to the face of the framing material; not to the side.  If you have the batts stapled that way, then they are not in contact with the air barrier.  This is illustrated in the Infared picture. Note the cooler colors near the top that are rounded and follow the framing down the wall, and the dark hole in the top of one wall cavity.


Batts showing air movement, not in contact

Batts not incontact with Air Barrier

A Fiberglass Batt must be covered on each of the 6 sides.

This one seems simple, in an exterior wall, the top plate, the bottom plate, the drywall, the exterior sheathing, and the framing constitute all 6 sides of the batt.  Now think about the wall that is formed between the end of the vaulted ceiling and the attic?  OK;  Drywall, Yes!; Bottom Plate, Yes; Top Plate, not usually; Framing, sort of; exterior sheathing, usually nothing.  So, we have 2.5 on these types of walls. Below is a picture of the end of two knee walls with no framing on a corner of a vaulted ceiling.

Knee wall from Attic Side

Solutions on Knee Walls:  Cover the top, back and the sides of the batts at the corners with an encapsulating material.  House wrap installed according to manufacturers directions is a good choice for an existing home.  Easy to get into the area and then apply.

A Batt should not be compressed.

OK!  Think about all the things running in walls.  Electric wires, pipes, CAT 5 cable; phone lines, cable TV, security system cables.

Poorly installed Batt Insulation

Poorly installed Batt Insulation

First, you have the installs that are done before the insulation is installed; typically the electric and plumbing.  The insulator can deal with these easily. The batt can be sliced, partly through, to allow the obstruction to pass through the middle, instead of stuffing the batt behind or pushing the batt into place on top the wire or pipe. It can be carefully cut to allow an electrical box.

Good Installation of Fiberglass Batts

Good Installation of Fiberglass Batts

For those tradesmen that follow the insulator, everyone else on the list above, it is not quite so easy. If they come before the drywall is up, then you may find holes in the kraft paper, and wires compressing the batt as it runs from 2x to 2x; or you may find something else. If they come after the drywall, your guess is as good as mine as to what the wall will actually be.

The infrared image below shows air infiltrating around improperly installed fiberglass batts on the other side.

Infrared Image Infiltration in Knee Wall


If you are renovating a wall in your house, and you choose to insulate; fantastic!  It will save you money.  Lots of insulation choices available, if you choose Fiberglass Batts, follow these concepts and you will maximize the effectiveness of your insulation.


The only other item you should do, when renovating and insulating is to air seal and stop those cold drafts. That is a subject of another post!

Insulation: How To Do Business with Customer Service in Mind Part II

Last Sunday I wrote a post about the Lawyers being sent to my friend and fellow Building Science Blogger Allison Bailes regarding a post on his blog.…ervice-in-mind/ ?

I received a copy of the letter from the President of Guardian Insulation to Allison late yesterday.  Allison provides the letter and his comments in his post today.

I am happy to see that Guardian Insulation can look at a situation and resolve it in terms of Good Customer Service.  Mr. Ziessler strongly indicated that Guardian would like to “engage the broader discussion with Allison and his readers about how to improve energy efficiency in homes and  the quality of installation across the spectrum of building products.”

I look forward to this join effort to improve the state of quality installs on any type of insulation.

Insulation: How To Do Business with Customer Service in Mind!

I do Home Energy Audits. When I am collecting the data from the home, I look at many things that effect energy usage. Equipment, Solar Orientation, Infiltration and the building shell (includes doors and windows), and Insulation are the major components.

I like insulation. A home with lots of insulation is like waking on a cold morning and feeling the warmth of the bed with the covers pulled up tight. Stick you pinky out or have the covers pulled and BRRR! Same with your home.

I like lots of insulation. The more the better. The only limit seems to be how many years will the current utility rates provide a payback. I try to keep my recommendations in the 10 – 20 year range. Beyond that, you can better spend your money for other improvements.

What insulation is best? All of them! I have yet to meet a bad type of insulation. All forms have their advantages and disadvantages. Some work better in one place, others in another place. Some work well in several places.

What differentiates the different types of insulation?
The color of the insulation?
The Manufacturer!
Probably not!
The installer hired to put your insulation in place!
Yes!!!! You’ve got it.

A good installer will install the insulation correctly! That means according to the specifications of the manufacturer and Industry Best Practices. Manufacturers specifications can be found on the Manufacturers website. Industry Best Practice can be found at Energy Star; Dept of Energy; and the Building Science Corporation.

When looking at different types of installed insulation – which is the one I see most often installed incorrectly? Fiberglass Batts!

Poorly installed Batt Insulation

Poorly installed Batt Insulation

This image shows an example. Compressed, miscut, uneven, stapled to the side of the 2x not the face.

Why are these problems not either following the Manufacturer’s Recommendations or Industry Best Practices? To maximize its effectiveness, Fiberglass batts need to be installed with no compression. The insulating value is their air pockets between the strands of fiberglass. Anything that results in compression degrades the performance of the installed insulation. In many cases badly installed insulation is no better than no insulation.

Good Installation of Fiberglass Batts

This image shows fiberglass batts installed correctly. The batt is cut around the electrical box, the wires do not compress the insulation, it is stapled to the face of the 2x and it is cut to the correct length.

So, what are the white spots in the photos? I took the brand name out. Why? My friend and fellow HERs Rater, Allison Bailes of Energy Vanguard recently received a letter from the lawyers for Guardian Insulation complaining that his blog post, similar to this one, defamed their product and their company! Why, because he left the name of the company on the picture of the batt that was installed in error of the manufacturer’s specifications.

    Why is the first reaction of some people to ‘call the lawyer’?
    Is that good business?
    Is that good for business?

I don’t know! No! No!

What could Guardian have done differently?

They could have supported their own manufacturers recommendations and worked to educate the installer to do a better job next time.

They could have a responsive technical assistance department to assist those installers and others who ‘want to get it right the first time’! Other manufacturers of Fiberglass Batts have these people – and they work well with those who ‘want to get it right the first time’!

Will Guardian continue with the lawyer track or move to a customer service track? Only time will tell.

For more information on the letter from Guardian and the story of batt insulation installed incorrectly you can go to Allison’s Energy Vanguard Blog at

or Martin Holiday’s Blog at