cellulose insulation

Tom_35

This is good stuff! Far, far better than fiberglass. It fills the crevices around electrical and plumbing outlets, and does an excellent job.

A lot of the guys that post here have experience with a foam product called Icyclene (spelling may be wrong). I've gone to the website and it certainly has excellent numbers. I don't know how it compares in price with cellulose, but would guess that it would be more.

By the way, the insulation won't burn. I've seen demonstrations where a person can have a handful of cellulose in their hand with a penny on top of the insulation, then take a small torch and heat the penny. Doesn't burn the hand and the cellulose doesn't burn.

The wall blown-in cellulose is mixed with water and then a trowel in run down the studs to bring the insulation flush with the wall (this is on new construction or remodel). The insulation has to cure before sheet rock is installed.
If it is blown into an existing wall, I would imagine that it would b blown in dry so mold and mildew would not be a potential problem.

Tom A

eburke_31

cellulose

I'm considering having cellulose insulation blown into my walls. Has anyone had this done? House is 60 years old and is drafty. I had a new boiler installed two years ago, and would like to increase house efficiency. Wood shingles on the outside. Concerns about cellulose are dust, allergies, fire, and mold. I have insulated attic areas, but the pros seem to have machines that will pack the walls well.
Any advice on this type of insuation would be much appreciated. ed

John Conway

cellulose

The December 2004 Old House Journal has a (too short) article on insulation of old houses (also a Dan Holohan radiator vent article). They like blown-in borate-treated (not ammonium or aluminum sulfate treated) cellulose. Better products exist, but how easily can they be installed? Then you must consider old wiring methods (my house is tube & post or whatever it's called) which can overheat if insulated. I'd love to hear professional, authoritative advice on this subject.

www.oldhousejournal.com

Mise, le meas

jeff_51

certainly been used for many years

you won't get every cavity filled 100%, with this or any blow in type, but cellulose has certainly been continualy upgraded in both installation techniques and product. You will see dramatic improvements in comfort and conservation. Insulation is the number one most cost effective use of dollars for reducing heating costs, with I think windows being number two ( unless the exisiting ones are pretty good). Just a note. Unless you strip interior or exterior sheeting, you can never guarantee full cavitys at 100%, but the installers have gotten very good so don't sweat that

Mike T., Swampeast MO

Old knob-and-tube wiring was meant to be air cooled, is of light gauge and is frequently overloaded. The cellulose may not burn, but it can lead to the wire overheating and only accelerates the decomposition of the old wire coverings. I'd be quite cautious if you suspect K&T wiring in the walls to be insulated.

Thad English

blown in

I had it done last summer. It makes all the difference. My stone home is 97 years old and had not a lick of insulation in the exterior walls. The attic had fiberglass in between the joists to a whopping r-11. We blew the attic to about a 2 foot depth (they apporoximate an r-30 value). We had the cellulose blown in between the stud bays into every exterior wall on every floor of the house. We even filled the steam chases with the stuff. We also installed storm windows where there were none, and improved the insulation on our steam mains in the basement. All 3 things done add up to a 30% savings in gas usage.

Matt_28

Air sealing

I am having my house insulated/air sealed this week. Air sealing with a blower door test is the other important part of insulating your home. Air movement through plumbing/electrical chases and openings account for a large amount of a homes heat loss. Don't forget this step when improving your homes efficiency.
Matt

Bob Vennerbeck

cellulose blowing tricks

My wife and I blew about 70 bales (22 pounds each - who decided on 10 kilo bales, anyway?) into a 2-1/2 story house early this winter - it was balloon framed in the late 1800's - we knocked out the kneewall plaster in the attic (was in rough shape anyway) - I duct-taped about 2 feet of 1-1/2 iron pipe to the end of 20' of corrugated bilge pump hose (that's what Home Depot called it anyway) and connected THAT to the blower hose - the weighted hose dropped down the stud cavity to the sill easily, and was pulled up slowly while blowing - we got excellent coverage/density in the stud walls, and managed to get good density under the attic floorboards. We could feel the building getting warmer as we worked around the perimeter. I would do it again in a minute, but would strongly advocate being more invasive than you really want in order to get the material into the walls.

Vbob

Mark Hunt

100% correct about knob and tube


DO NOT cover knob and tube wiring.

As Mike said, it needs to be exposed to the air.

Mark H

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Mark Hunt

The most commonly used


cellulose has fire retardents and mold inhibitors in it.

When the cellulose is blown in under pressure or "wet packed", you couldn't squeeze a drop of water out of it. VERY little water is used, so there is really no drying time.

It stops air infiltration and has a better r-value than fiberglass.

Mark H

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jerry scharf_2

This may not be the case

Mark,

I too am a big fan of dense pack cellulose for retrofits. Unfortunately, I have been tracking some recent research that has shown mold development in these installations. I have asked for more details, but have not heard back from the researcher yet. The detailed research in the cases seem to strongly indicate that the moisture supporting the mold growth did come from the installation process. It would be a real drag if it were true.

jerry

Mark Hunt

Geeze Jerry


Keep me up to date on that please.

I can't understand how the cellulose could bring that about since it has mold killers in it.

I was at a mold seminar a few years back and the speaker was an amazing man from Canada. He told us of a study performed in Canada where a sample of sheetrock was taken from the assembly line and placed in a plastic bag. It never left the factory. Within two weks it bagan to grow mold. It was later determined that the mold source was the factory!!

I would be quite suprised if the cellulose was found to be the source of the mold.

Mark H

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PS

Tricks

Bob,
I too have a balloon framed house and am looking to do a DIY blown in cellulose job. How did you manage to NOT fill your 1st floor ceiling joists? With this type framing - the floor/ceiling joist cavities are open to the exterior framing.

BTW - Nice trick with the weighted hose!

Norbert

choosing an insulation installer

Can anyone give tips on choosing a contractor for this type of work? Is there a trade/pro or certifying group?

I also suspect that I should do any wiring upgrades before any insul install, especially blown in, can't imagine trying to snake down a wall with this stuff in it.

PS

Norbert,

I am doing this on my own but most insulation companies provide this service. Be sure to get a few quotes and check references - blowing in existing walls, especially older houses, carries the risk of damaging interior walls.

As far as updating your wiring - I (have) would do this before insulating. Good luck.

jerry scharf_2

It's not the source of the mold

Mark,

Mold spores are everywhere. Mold food is everywhere. The key is the moisture. So even of the inhibitor prevented mold growth in the material, it could still provide the moisture needed to support mold growth on the sheetrock paper or wood studs.

The example you gave me doesn't surprise me one bit. The bag trapped the moisture from the manufacturing process, and that's the magic third piece to get the mold bloom. Thanks, I'll be using that as an example when I talk to people in the future.

There have been documented cases of borate treated dense pack cellulose retrofit and mold. The forensics seem to indicate that the moisture source was the insulation. It really is going to take many more cases before there is a clear pattern and a causal relationship is determined. It's a long step from corrolation (they happen together) and cause (the insulation caused the mold problem.) I'm guessing it will be a few more years before this is sorted out. Really sucks, doesn't it!

Yes, I'm truely sad if this is true. Partly because I have recommended this to many people. Partly because I know of no other good, easy solution. I've talked to foam people about the Icynene retrofit work, and it's really hard to do right. The problem is how do you find voids that form during the fill and foam process. One group who does alot of this uses an IR camera to watch the fill for cold places where the chemical reaction isn't happening...

jerry

mac

Dense blow is...

.. the way to go. Doing a balloon framed house from the attic with the weigthed hose described earlier is the way to go.. I did my first house and when slowly lifting up the hose, you could hear the blower bog down slightly when it was packed in well. Time to back it up a notch anf fill the next section.

regading old "Knob & Tube" wiring: Don't do it, as Mark said it needs to "breath". Something to be said for the peace of mind knowing you've got decent wiring before sinking in a LOT MORE MONEY!

PS

So does "dense pack" always mean water added? I have read it referenced "dry" as well. Can you not simply increase the quantity of dry cellulose per unit volume and get the same R value, or like fiberglas depends on non-compaction? Seems to me introducing any moist substance into a sealed cavity is asking for trouble, even with inhibitors. As the word infers - it is an inhibitor, not an absolute preventative.

billygoat22

I've seen the Icyrene go in before. I'd be surprised if that stuff did have a void. It found every single chink in the blocl walls they were filling.
You could stand there and see little blobs on the wall where there was the slighest gap in the mortar- wouldn't notice if not for the white stuff oozing out. Glad I'm not the electrician, about 1/2 a wheelbarrow came out all the elec boxes in the walls!

jerry scharf_2

it's glue

The wetness is actually a glue that goes in with the cellulose as it is installed. The glue is water based and dries. The glue is the key, it prevents settling and makes the air barrier. Settling it the critical problem with blown in insulation. If the insulation settles to produce a 5% void at the top of a stud bay over 10 years, as a rough number you have to derate the wall insulation by 50% in the difference between an uninsulated wall and the insulation value. The glue keeps the cellulose in place, and you don't need to age derate it.

jerry

Bob Vennerbeck

Much to my suprise, using my homemade weighted hose, I could actually look down inside the stud bay while it was blowing - if I kept the weighted end of the hose 'submerged' in the cellulose already in place there wasn't much dust. I just kept bobbing the hose up and down a bit - kind of like vibrating concrete - and I could hear and feel when the flow was slowing down. When I got to the halfway point, where the open 1st floor ceiling joist bays intersect the stud bays, I pulled up the hose a bit more quickly, and the material already placed seemed to keep it from flowing too freely to the interfloor space - certainly some went sideways, but it didn't seem to be much, and I couldn't really think of a good reason why I cared if it did. At the top of the wall, I could push the hose sideways under the attic floorboards, and I made a concious effort to fill that space - the attic is now cold storage, but it was before anyway. If we ever decide to refinish the attic space, the cellulose under the floor will keep the noise down.

Larry Weingarten

Another consideration...

...is whether there is a vapor retarder, like poly, used on either side of the cellulose. If water is prevented from leaving the insulation, mold is likely. I'd be slow to blame the insulation unless the rest of the wall's construction is known to be right for the climate. http://www.buildingscience.com/ is a good source of info.

Yours, Larry

PS

I have old, heavy plastered ceilings and I'm not too keen on adding any more weight, not to mention I don't want to waste insulation. Thanks for the help.