[Greenbuilding] Cellulose blowing tools/techniques

[Robert Waldrop]

Two years ago we insulated our 1929 Craftsman 
bungalow with Cocoon insulation.  We did it 
ourselves, and none of us had ever blown 
insulation before.  It was very easy to learn. 
The main problem we had was the machine we 
originally got for free from Home Despot was not 
strong enough to fill the wall cavities.  We went 
to a rental store and got another machine and it 
did fine.  For the wall cavities, we would keep 
the hose in the hole and the blower going until 
the machine started to choke from being unable to 
push more material in, then we would stop and go 
to the next hole.  There would always be a little 
puff of insulation when we took the hose out.

After we filled our original walls, we put sheet 
rock over the new frame that we had constructed 
5.5 inches inside of the original exterior walls, 
and filled those holes.  So now we have 9 inches 
of cellulose insulation in our walls, and we like 
it a lot.

A year later, consumed with curiosity, I drilled a 
half dozen holes in the walls to see if the 
insulation had settled or turned into green goo or 
oozing mold or any of the other numerous horror 
stories that people tell about cellulose 
insulation.  Each wall we checked remained tight 
packed.  There had been no settling.  I think some 
of those stories originate in the marketing 
departments of fiberglass insulation corporations.

We also did our attic.  That was easy, but it is 
very dirty for the person in the attic.  An 
excellent respirator and goggles are mandatory.  A 
coverall also helps as the cellulose gets all over 
the clothing.

It is a 2 person job -- one to wield the hose, one 
to run the machine outside.  We rigged a rope that 
the person inside would pull when he wanted the 
machine turned off, as the one we rented didn't 
have a control that could be used inside by the 
worker with the hose.

Your third method won't work, with a blower, 
unless you installed a 2 x 4 or something to hold 
the insulation in the bottom half. Otherwise, it 
will just blow up out of the cavity into the room. 
The Cocoon insulation bales are tightly 
compressed, and they need to be broken up before 
being blown into the wall (the machine does that). 
I guess you could break it up and then pack the 
walls by hand, but I think the blower would be 
easier.

I also can't imagine the poly sheeting working 
with dry cellulose.  It seems to me that it would 
bow out under the pressure of the material.

I suggest simply following the manufacturer's 
instructions.  I am not a professional builder, 
but as an amateur I found cellulose insulation to 
be easy to install according to the manufacturer's 
instructions. Just keep that hose blowing into the 
wall until  it won't take any more.

If your hose clogs a lot (like every 20 minutes or 
so), go get another blower.  We wasted a whole day 
futzing with the Home Despot machine, trying to 
make it work, when the plain fact was that it was 
under-powered for the job.  About every 20 minutes 
it would clog.  The machine from the rental store, 
however, worked like a dream and only clogged a 
couple of times during the rest of the work.  The 
Home Despot machine would have been fine probably 
for the attic, which is probably what most people 
used it for, but it was underpowered for walls.

The winter after we did that insulating, we hardly 
needed any backup heat (we also tore off the south 
wall of our utility room and added windows to 
collect solar heat).  Last winter we needed more 
backup heat, but we also had an unusual (for us) 
amount of cloud cover.  We don't regret the work 
at all and are glad we did not yield to the 
numerous "nay-sayers" who constantly went on about 
how we were installing too much insulation, and it 
would never work and the cellulose would settle 
and turn into green ooze and kill us with nasty 
diseases. Yadda, yadda, yadda.  Me, I look at my 
$50/month electric bill and consider the work and 
money to be an investment that is paying me 
tax-free interest (in the form of energy I no 
longer have to buy to stay comfortable in my 
house) for the rest of my life.

Bob Waldrop, Oklahoma City

----- Original Message ----- 
From: "Jefro" <jefro at jefro.net>
To: <greenbuilding at listserv.repp.org>
Sent: Friday, June 01, 2007 5:23 PM
Subject: Re: [Greenbuilding] Cellulose blowing 
tools/techniques


>I have been following this thread with grave 
>interest, as I am in the
> same position---about 3 or 4 weeks away from 
> installing cellulose into
> my 2x10 wall cavities.
>
> As I see it, I have three options if I want to 
> do the job myself---and
> given the financial realities of house building, 
> I will be doing it
> myself.  I'll be using Cocoon cellulose, which 
> is manufactured about 150
> miles from home, and installing with a rented 
> blower.  This will be a
> dry install.  Options are:
>
> - sheetrock first, drill holes and install as a 
> retrofit per manuf.
> instructions
> - install poly netting and blow through it, and 
> hope for the best
> - sheetrock the lower half of the wall, fill 
> with cellulose, then do the
> same with the upper half
>
> I can see advantages and disadvantages to each 
> method.  Will probably do
> a test run using each method on a couple of 
> different wall sections
> first, to see which goes fastest and which seems 
> to fit most densely and
> thoroughly.  I'll also do a "settle test" by 
> drilling holes at the
> ceiling in a couple of months and topping off 
> where necessary.
>
> For the third method, I wonder if it would be 
> advantageous to forego the
> blower, just sheetrock up 4 feet and dump the 
> stuff into the well, and
> then compress or tamp down by hand before adding 
> the top layer.  Any
> thoughts?
>
> BTW, I estimated about 105 "bags" of insulation 
> per the manufacturer's
> recommended coverage.  (They list for horizontal 
> blowing, mine is inside
> vertical walls so I added 10%.)  The hardware 
> store rents the blower for
> free if you buy enough insulation.  That means 
> that ALL of the wall
> insulation to fill 2x10 walls in a 1600sf 
> two-story house for approx.
> R29 walls, will cost about $1100.  That beats 
> fiberglass by a long, long
> margin, though of course doesn't count the roof.
>
>