Intro to Insulation
An Introduction to Cellulose Insulation
Would it surprise you to learn that cellulose is the most common building material in the world? It shouldn’t, because wood is cellulose, and you’ll find more wood used in construction than any other material. You might be tempted to think of cellulose insulation as paper, or even ground-up paper, but in fact it’s not. While clean, recycled paper and cardboards form the basis of cellulose insulation, National Fiber processes it back to a fibrous state, bearing no resemblance to the original paper. (The same can’t be said for all makers of cellulose insulation, however.)
A Little History
Cellulose insulation has been around a long time. Thomas Jefferson used a form of cellulose to insulate his estate, Monticello – where construction began in 1769! What we think of today as cellulose insulation has been in wide use since the 1920’s, growing dramatically after WWII. The energy crisis of the 1970’s and 1980’s led to even greater use of cellulose – and the reputation of cellulose as an insulation that would settle in your walls. That’s no longer the case, and it hasn’t been for a long time, thanks to dramatic improvements in manufacturing and installation techniques.
Cellulose Insulation Fire Safe
National Fiber’s Cel-Pak is, like most things, a much better product than you could buy in the 1970’s. First, it’s completely fiberized, which allows for interlocking of the cellulose fibers. Then there’s the equipment and techniques used to install it – both radically improved from the ‘good old days’.
Today, Cel-Pak is ‘dense-packed’ in walls at a density of 3.2 – 3.5 lbs of material per cubic foot of space, or more than twice its settled density. This does a couple of things. First, the installation process ensures that cavities are completely filled – no gaps, no voids, no pockets or spaces.
Second, using 3.5 lbs. of material per cubic foot ensures that the material is under slight pressure in the wall cavity. It simply can’t settle, because there is no room for it to settle. (Those displays you see at trade shows showing cellulose blowing around in a box? They’re designed to trick you, using far less material than is installed in the field, so don’t be fooled.)
Big Burn, National Fiber Blown-In Cellulose vs Fiberglass Insulation
The Bottom Line
Cellulose has improved in quality and sophistication over time, and it now provides exceptional resistance to fire, moisture, mold, and vermin. No other insulation can claim these benefits and also provide the superior thermal and sound insulation that comes naturally to cellulose.
Facts About R-Value
Some quick facts about R-value are:
- One type of insulation maybe thicker or thinner, but if the R-value is the same they should insulate equally.
- R value performance testing is done in a 70 F environment with no air movement. Ironically enough, when you need insulation the most you’re generally not in these ideal temperatures or conditions. This can result in the rated house insulation R-value being higher than the actual effective R-value.
- The average recommended R-value of insulating material for basement insulation in North America is R-12.
- The R-value in house insulation is substantially lowered when there’s any air or water/moisture leaks.
- The standard R-value for house insulation varies based on climate and temperature
- 1 inch of insulation is = to 30 inches of concrete.
There are different types of house insulation materials, each having a different R-value.
Some of the best insulation materials are:
- House Insulation R-value of Blown-In Cellulose Insulation is 3.70 per inch
- House Insulation R-value of Fiberglass Insulation is 3.14 per inch
Insulation Removal
Blown-In Cellulose vs Fiberglass Insulation in Performance
The R-value between blown-in cellulose insulation and fiberglass insulation are the same but the thickness varies. On average, blown-in cellulose insulation is 2-3 inches thinner than fiberglass insulation when both have the sameR-value. Both blown-in cellulose insulation and fiberglass insulation perform well to insulate your home. However, regardless of which insulation you choose, the performance of the insulation varies greatly on the quality of workmanship. This is generally true more so for cellulose insulation than fiberglass insulation. in addition cellulose insulation could cause some corrosion on metal that it touches but can also insulate the entire cavity of the wall and flow around wall studs while fiberglass insulation may not cause corrosion but it cannot flow around wall stubs as it has to be placed there. However, this is generally not done.
Blown-In Cellulose Home Insulation and Fires
Blown-in cellulose insulation is treated for fire retardancy. If a fire occurs, the blown in cellulose insulation, combined with its fire retardants, can slow the fire from spreading and can create a “2-hour firewall”. Scientists at the National Research Council of Canada Reported that blown-in cellulose insulation increases fire resistance by 22%-55%. When blown-in cellulose insulation does burn, it generally doesn’t emit toxic chemicals.
Fiberglass Home Insulation and Fires
Fiberglass insulation is inert, ages well and is extremely difficult to ignite. However, once fiberglass insulation has been ignited, it may burn fast, hot and could emit toxic gases. Also, fiberglass insulation should be kept away from, light fixtures, chimneys or exhaust flu’s to reduce heat build-up and potential fire hazards.
Blown-In Cellulose Insulation Installation
When installing cellulose insulation you will need special cellulose insulation equipment such as a cellulose insulation blower. Blown-in cellulose insulation easily flows around obstructions and penetrates odd shaped cavities and it easily conforms around wires, electrical boxes and pipes. However, cellulose insulation is mixed with water and can take anywhere from 72 hours to over 1 year to completely dry. The drying time depends on the installation mix, moisture retarder, temperature and climate when the drywall is installed.
Fiberglass Insulation
Some fiberglass insulation facts on installation are: it has to be installed carefully, small fibers can cut your skin meaning you must wear protective equipment. Having to cut the fiberglass insulation to fit around wires, electrical boxes and pipes can be difficult and time consuming. Fiberglass batts are currently the standard insulation attributed to savings in residential and commercial buildings throughout the U.S.
Blown-In Cellulose vs. Fiberglass Insulation Air Infiltration
Blown-in cellulose insulation is 2-3 times denser than fiberglass insulation. Studies comparing blown-in cellulose insulation vs fiberglass insulation show that cellulose insulation was 38% tighter and required 26% less energy. A Princeton University study shows, a group of homes with blown-in cellulose insulation in the walls had an average of 24.5% reduction of air infiltration compared to fiberglass insulation, with only the walls insulated. A similar study, the Leominster MA Housing Project for the Elderly found that, a building with blown-in cellulose insulation compared to a building with R-13 fiberglass batt insulation in the walls and R-38 fiberglass batt insulation in the ceiling, had 40% lower leakage. However, when it comes to air infiltration, sheathing and drywall are better air barriers than any cavity insulation. Air infiltration barriers such as high-density polyethylene membranes are installed for this specific purpose.
Blown-In Cellulose Insulation and Moisture
A blown-in cellulose insulation vapor barrier is a must. Due to its chemical content, cellulose insulation may be more moisture resistant than fiberglass insulation. However, blown-in cellulose insulation is mixed with water and if it is not given a proper drying time before the wall cavity is sealed up, studies show that it could retain the moisture in the insulation for over a year. There are currently no clear and reliable drying guidelines for cellulose insulation.
Fiberglass Insulation and Moisture
Fiberglass insulation construction, allows water vapor to pass though its fibers. However, when water leaks through your wall with no drainage, fiberglass insulation may absorb the moisture and cause sags and gaps in the wall. These sags and gaps can allow heat in your house to escape. The end result would be, your R-value is lower and your heating costs are higher.
Click here to read more on fiberglass Insulation
Blown-In Fiberglass Insulation – Use With Caution
There is a family in Florida that was exposed to friable fiberglass that has caused a serious health problem for the family. The wife recently had a baby and was concerned about an itching on the skin feeling that she and the other members of the family were having. The family of five experienced a variety of eye, ear, skin, and respiratory problems. She was also complaining about a lot of white dust particles all over her furniture and personal possessions
Six months prior to this time, the family had a licensed Insulation Contractor blow in additional insulation on top of their existing Builder installed Batting Insulation. They wanted to save money on their electric bill and thought this was the right way to go. Even the Power Company got into the act by giving them an incentive award to increase the R-value of the insulation of the home. Sounds great doesn’t it. Well this is only the beginning of a nightmare for this family.
We were called in to do an Indoor Air Quality Investigation and discovered that they had the old style recessed lighting in the ceilings. There were approximately 20 of these fixtures. The problem with the old style lighting was: there were four slits on the attic side which allowed the heat of the lights to dissipate. These slits were 3/8″ X 2″ long. This equates to approximately a 2″+ hole in the ceiling at each location. Multiply this by 20 lights and you get a 40″ hole in the ceiling total. Wow, that’s a big hole in the ceiling. These holes prevented the lights from overheating and causing a fire. This is a great concept for a fire hazard, but a bad concept for Indoor Air Quality and Blown-In Insulation. The one requirement with these old style lights was you could not cover them with Insulation Batting. We found multiple recessed lights with Blown-In Insulation covering them and inside the lights also.
After doing several air and tape samples, sending them to a lab, the results came back positive for fiberglass in the air and surfaces of areas tested. The first thing we requested the client do was to remove and install the new sealed recessed lighting in the house. They hired a licensed Electrical Contractor, removed all the fixtures and solved the air intrusion problem from the attic. That was only the beginning of the fix, then they had to HEPA Vacuum and clean everything in the home to remove the friable fiberglass particles on the surfaces.
How would you like to live this nightmare for over one year due to the incompetence of one contractor who did not think the job through?
This is only one example of what is going on in our building industry because of poor planning on the part of the contractor. Remember, you get what you pay for; the low bid isn’t always the right person for the job.
If you decide to add insulation to your attic, check with the Insulation Manufacturer and see what their requirements are before hiring anyone to do the job. Have your attic checked out first to see if there are any holes leading into the attic that can allow air intrusion into your home. If you do this, you will not be faced with this type of problem.
Next on the list, have the duct work checked for any type of leakage and sealed. Check all your electrical fixtures in the ceiling and seal them. Make sure the person who does the repairs is competent and knows what they are doing or it will affect you in the long term.
Myths & Misconceptions
Cellulose settles in your walls
Dense-packed cellulose doesn’t settle, because it can’t. It’s installed at twice its settled density, which means that it’s under slight pressure in the wall or ceiling cavity. Those home show displays that show cellulose settling, or worse, blowing around in a box? They’re tricks. They’re purposely under-filled to promote the myth that cellulose settles and help them sell you some other product. Don’t be fooled.
Cellulose insulation is made from newspapers, so it will burn
Cel-Pak and Nu-Wool have an 83% recycled content, primarily over-issue newsprint and other ground wood paper sources. The paper is fully fiberized (reduced to cellulose fiber) and infused with borate, a naturally occurring mineral. Borate gives cellulose a Class A fire rating. In fact, a cellulose insulated structure is arguably safer than one insulated with another insulation, because borate treated cellulose helps limit the spread of a fire and produces no smoke.
Cellulose is expensive
As a rule, cellulose insulation costs more to install than fiberglass and less to install than sprayed foams. Because it saves so much more energy than fiberglass, the extra expense is quickly recovered, and the savings just go on and on. Because cellulose offers better or comparable savings to typical sprayed foam installations, you save money on installation, and the savings just go on and on. So the right answer is that cellulose represents the best value, dollar for dollar, among common competing insulations.
Cellulose produces funny smells
National Fiber’s Cel-Pak and Nu-Wool cellulose insulations are all borate formulations (for fire, pest and mold resistance). Borate is on odorless mineral that doesn’t outgas, which is a fancy way to say National Fiber’s cellulose products don’t produce funny smells. Some cellulose manufacturers use an ammonium sulfate/borate mix. That can produce objectionable odors, under the right conditions. If you insist on our all borate formulations, you’ll never have this problem.
Houses need vapor barriers
Cellulose insulation requires no vapor barrier in the overwhelming majority of installations. It does an excellent job of limiting air movement, and because it is hygroscopic, it manages moisture as well. Some insulations require vapor barriers because they do such a poor job of preventing air movement, air that can carry moisture with it. The problem is that, where we live, moisture and air don’t always move in the same direction through a building, depending on the time of year. So what about those products that need a vapor barrier? Effectively, half the year it’s on the wrong side of the wall! Cellulose doesn’t have that problem.
Sprayed foam insulations can be green, too
Sorry, no way. The only thing green about sprayed foams is the money you pay for them. Sprayed foam insulations are made with petroleum and petroleum byproducts, and that just isn’t green.
What about soy based foams?
Sorry, not green. First, they’re not soy ‘based’ – they contain a small amount of soy additive. While soy added to foam does save a little bit of oil or chemicals, the soy had to be grown, watered, fertilized, harvested, trucked, processed – well, you get the idea. Foams with soy additive are heavily marketed for their soy content, which is something called ‘greenwashing’.
Unlike cellulose, foam insulations air seal and insulate at the same time
They can, certainly. But we have a lot of experience inspecting structures in the field that says that foams, especially the more rigid foams, don’t have the flexibility to move as the structure does. That means there can be separations between the foam and the framing members as the lumber dries, shrinks and moves, which can allow air infiltration. In addition, there are areas that aren’t routinely foamed, like the junction of a wall’s bottom plate with the floor, or top plate with upper story framing and flooring. The bottom line is that proper installation of any insulation should include air sealing.
R-Value is R-Value, so if the numbers are the same, the products perform the same
R-values are determined in labs, and they only measure one of the (4) ways that heat moves through a wall. For instance, there’s no wind in a lab. So if we compare an R-19 fiberglass wall to an R-20 cellulose wall, say, in February, on a 20-degree day with a 20-mile an hour wind, that fiberglass wall is delivering actual performance around R-11. The cellulose wall? Still R-20.
I just want my insulation to do a good job insulating
Of course you want your insulation choice to do a good job insulating. But to do that, it has to do a lot of things – effectively prevent air infiltration, manage moisture, etc. And you don’t want it to create problems – make a good home for pests, outgas, etc. And then there are things you want it to do that you might not associate with an insulation product, like make your home safer in the event of a fire, do the best job of reducing noise, and have the least impact possible on the environment.
National Fiber’s Cel-Pak do a great job at all the things a great insulation should do, with none of the potential downsides.
Cellulose is made from paper, so if it gets wet, that’s a problem
First, no insulation will handle a failed structure or assembly that is allowing liquid water to enter in any meaningful quantity. None.
With that out of the way, the other moisture that you find in walls is airborne humidity. Among commonly used insulations, cellulose is the only one that can manage this moisture by dispersing it and transporting it through the cavity. In other words, cellulose manages the natural moisture drives that occur in every structure. No other commonly used insulation product can make that claim.
Sprayed cellulose is applied wet – and that’s a problem
Nope. Spray applied cellulose, which is most often used in new construction, is damp-sprayed, not wet – an important distinction. In the old days, it was a wet applied product, and you could squeeze liquid moisture out of it. For quite some time now, only a very small amount of moisture is added to damp-sprayed cellulose, definitely not enough to be able to squeeze water out of it. Under normal conditions, the cellulose is ready to be covered by drywall in 24 hours, far less time than is routinely scheduled between the insulation and the drywall jobs. In addition, cellulose manages moisture. (see ‘Houses need vapor barriers’, above)
I just need to insulate my attic, so can I do it myself?
Well, you can – but that doesn’t mean you should. There is a proper way to install cellulose, and lots of ways that aren’t. A proper loose-blown attic job will be inspected for problems, may have old insulation removed, have the soffits blocked off, have air-sealing done – you get the picture. There’s more to it than just renting the machine and blowing the cellulose. (And lots of those big box cellulose products aren’t as clean as National Fiber’s, and many have ammonium sulfate in them – see ‘Cellulose produces funny smells’, above) Besides, don’t you have better things to do with your weekend?
Whether your home was built a century ago or just completed, it’s probably not too late for you and your family to enjoy the benefits of cellulose insulation! A simple, quick inspection by a CTHandiman, Inc insulation professional is all that is needed.
