Hi,

I'm wondering if anybody knows about this stuff called blow-in cellulose insulation?

The insulation in our 3 attics is not the best (even the inspector mentioned this when we made an offer on the house), but we haven't had a chance to look into upgrading it yet.

Anyway, someone was telling me about cellulose insulation which seems to be made of ground up newspaper with a fire retardant added. Apparently it's blown into the attics via a large gauge hose, creating almost 2 feet of depth on the flooring of the attics.

This is supposed to act as a great insulation, possibly better than fiberglass and/or anything that you would put on the actual ceiling of the attics.

Anybody know of this or have any experience with this?

Thanks.

---

My music blog: [www.auditorymusings.net]


The Garden of the Gods in Colorado Springs, Colorado

It has been in my attic for 36 years. It's a great insulation. Don't worry about it being made of old newspapers. What's the difference?

So this stuff just coats the flooring of your attic, correct?

We have all of our horizontal plumbing pipes basically snaked all over the floor of the attic, so this stuff would essentially bury all of that?

What if we need to get to some of this piping at some point in the future?

I had it blown in between the walls of my 112 year-old victorian house. The contractor drilled a 2" hole in my interior walls between the studs, blew in the cellulose and then patched the hole back up.

The work wasn't cheap....IIRC, it was $1000 for 2 rooms.

I noticed a slight savings in my insanely expensive heating bill, but what I noticed the most was that I no longer heard noise from the busy street outside my bedroom or living room.

pinkoos, any insulation you put in and around the piping will make access difficult. If you need to repair, you'll have to vacuum/dig it out.

And... what KIND of pipes do you have in your attic ? They are quite probably vent stacks. Right ? No actual water running in your attic (where it can freeze, etc..) ?

That stuff is very convenient to use in attics that are difficult to access. it also fills voids quite nicely, which helps too.

Be absolutely sure that you don't compromise your attic ventilation... it's necessary to install baffles to protect the airflow from soffit vents and so forth before you blow. And if an insulation contractor tells you 'you don't need to worry about that', run away.

It's our PEX plumbing pipes, running all through the attics and then snaking down the walls to the fixtures.

Any reason you can't look into insulating the attic roof and walls? My house is probably closer to Poochies' house and although the attic is unfinished, I would like to finish it one day so I'm probably going to insulate the attic. But, I'm going to have it done via expanding the thickness of the roof rafters from the exterior. I can then come into the house and do an additional layer of insulation in the existing rafters.

---

Hurts like a bastid...

Pinkoos... you must live where it doesn't get below freezing ?
mrbig....

Finishing an attic requires VERY careful work to ensure that the roof ventilation is kept intact. Otherwise you end up with roof damage, condensation in the attic rooms, etc... The attic is the 'hat' of the house. Just like a properly ventilated hat in the summer keeps you cool, so does your attic.

What Cbelt said about ventilation.

About cellulose - what happens if it gets wet?

If cellulose gets wet you end up with a papier mache insulation. It's messy.

if fiberglass gets wet it gets messy too.

Water in an attic === Badness !

Any wet insulation has to be removed as part of a roof repair process.

when renovating a roof, it's a fairly straightforward process to leave a gap between the rafters and the sheathing, with an air pass from the eaves. not saying I"m going to do the work personally, but I've discussed it with contractors.

---

Hurts like a bastid...

Blown in cellulose is excellent insulation. Before it goes in, have them attach sticks adjacent to the pipes that will stick up above the insulation and show you where the pipes are. Also take photographs of the pipes before the insulation job.

As mentioned above, it is critical to make sure all attic vents are protected before installation. Also, it is critical to have the contractor seal all plumbing and electrical lines that pass through the attic floor using impermeable material (i.e. aerosol foam, NOT stuffed in insulation). This will make the insulation job much more effective. Make them pull up your old insulation to check all the lines. Lazy contractors won't do these things because they will be hidden after the insulation is installed.

One more thing...since you live in Texas, you probably have the issue of too much heat in the summer, right? Insulation will be only marginally effective against that. Have them install radiant barrier between the rafters above the insulation. That will keep a lot of the heat out. Also, have them check to be sure your attic is adequately vented. Poor venting makes all of that insulation virtually useless during the summer.

---

"In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion." (1987) -- Carl Sagan



Edited 1 time(s). Last edit at 11/14/2012 10:19AM by davester.

Ah.. Texas ! Whew... Hmm.... pinkoos... ever think about just putting a nice big 'ol loop of steel pipe up there to act as a hot water reservoir in the summer ? Betcha you won't need to use your hot water heater much ! Of course you'd need to bypass that sucker in the winter...

I did this for my son's house. "Rented" a blower at Lowe's for the day (which I think was actually free if you bought the insulation there). As I recall, it was maybe $500 total (DIY) to add ~8" of insulation depth in a ~24x60 ft attic.

Will second (or third, or fourth) the comments re ventilation; I put formed styrofoam baffles between the rafters of the roof down low toward the eaves to leave a path for air to rise up through the eaves and over the insulation, and out through end or roof vents (assuming you have eave vents- if you don't, put them in). Make sure you have a vapor barrier below the insulation. Good idea to mark the pipes. I also nailed down two 2x12's laid on end across the ceiling rafters, next to the ceiling access panel, to serve as a support for a 4x8 foot plywood sheet that went _over_ the insulation when it was all done, to make for a small attic storage spot. And you may need to build a box out of 1x12's around your access panel to hold back the insulation.

Then blast away, for a few messy, dusty hours. Start at the farthest end from the access panel, working your way back toward said panel. Then, wash off in a long hot shower, and start to enjoy a quieter, warmer home with lower heating bills.

My house had it blown in in the late sixties , early seventies.
Attic and walls.


Diminishing returns with increased depths, but cellulose is a rather old and time proven product.

It can be topped over whatever you have now as long as what you have now is not defective.

Absolutely air-seal first.

Maybe your state has an energy program in place where your house can be tested for leaks and the leaks identified ?

---

The Phorum Wall keeps us safe from illegal characters and words
The doorstep to the temple of wisdom is the knowledge of one's own ignorance. -Benjamin Franklin
BOYCOTT YOPLAIT [www.noyoplait.com]
[soundcloud.com]

Thanks for the great and informative replies. Looks like its not as straightforward as I initially thought.