How to Make and Install Your Own Insulation

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Learn how to make and install your own insulation on the cheap.
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Chart: R rating of common insulation materials.

Learn how to make and install your own insulation using newspapers and a farm-type hammermill.

How to Make and Install Your Own Insulation

Sometimes it’s going to happen for the “right” reason
(genuine dwindling reserves of the easily tapped fossil
fuels on which our society has become so desperately
hooked). Sometimes it’s going to happen for the “wrong”
reasons (Carter’s fiasco of massive new government meddling
and crushing taxes masquerading as an energy “plan”, say,
or profiteering by the utilities, multinational
corporations, and others who supply the oil, gas, coal,
electricity, etc., that we all use). And sometimes it’s
going to happen for both the right and the wrong reasons at
the same time.

But for whatever reason or combination of reasons it takes
place, there’s no question about what’s going to happen:
The price of all the “traditional” (fossil fuel and fossil
fuelderived) energy you use from now on is going to go in
just one direction . . . UP!

Oh, there’ll be welcome little short-term reversals of that
basic trend from time to time. (Right now, for
instance — thanks to new production from Britain’s North Sea
fields, Mexico’s sudden exports of oil, the opening of the
North Slope in Alaska, increased pumping in Saudi Arabia
last summer, and some other factors — the world is mildly
awash in petroleum, and there’s some rather frantic oil and
gasoline price cutting going on behind the scenes.)

For all practical purposes, though, these fleeting
discombobulations can be ignored (after, of course, you’ve
taken maximum advantage of them whenever they present
themselves). Keep your eye on the basic trend. And that
very basic and very, very strong trend — now, and for
as far into the future as you can possibly care to
peer — is for the price of all “traditional” forms of
energy to rise and rise and to keep on rising.

Then again, there’s nothing engraved on — a stone
tablet anywhere that says you have to remain a big-time
captive customer of the fossil fuel industry in the first

You might, for example, build and move into an Andy
Davis-type underground house (see The Plowboy Interview in
MOTHER NO. 46) . . . and then sail completely through the
coldest winter in over 100 years (the winter of 1976-77) on
only $1.29 worth of heating fuel the way Andy just did.

Or you might have David Wright, who now lives in a 93%
heating and cooling self-sufficient home of his own design
(see The Plowboy Interview in MOTHER NO. 47) draw up a set
of plans for your family.

You could even have Jesse J. Savell (See “Here’s a
Passively Heated and Cooled House That You Can Afford …
and Will Want”) put up one of his energy-miser dwellings for

But What if You Can’t Afford to Move Into One of
Those New Energy-Efficient Homes?

“Well, that’s all very nice,” a number of you have recently
told us, “and we certainly thank MOTHER for bringing these
new breakthroughs in energy-efficient housing to our
attention. But we can’t afford a place like that just now.
We’re going to have to stay where we are for a while. And
we aren’t even sure we can afford that! What can we do
right now to cut the amount of energy we’ll have to use to
keep our current home warm this winter? And don’t tell us
to have insulation installed . . . because we can’t afford a
bill for $300 or $400 or more for that either and, besides,
most of the contractors who install insulation have a
backlog of orders as it is.”

You Can Make and Install Your Own Insulation!

But who says you have to pay today’s outrageous prices for
insulation? (One contractor we know hiked his prices three
times in the month of August alone!) And who says you have
to put your name in the pot and then patiently wait days or
even weeks until an insulating firm can get to you?

Nobody, that’s who! Not when you can quickly, safely, and
easily manufacture one of the best insulations ever
devised. Not when you can make that insulation to equal or
far exceed the specifications (fireproofing, vermin-
proofing, etc.) of any manufacturer in the field. And not
when you can do it all by yourself in your spare time and
for just one-fifth or less of the out-of-pocket cost of
what a probably inferior insulation would set you back if
you hired a contractor to install it for you.

Yeah, sure. This all sounds too good to be true. But that’s
only because you’ve spent your whole life being brainwashed
into The Perfect Little Consumer. And that’s not your
fault. Nowadays, even the mechanics and shop magazines
(which, 30 years ago, would have given you exactly the sort
of information that MOTHER is now gonna lay on you)
maintain the polite — and, for you, expensive! — fiction
that insulation somehow isn’t actually insulation unless it
comes in a trademarked bag and a “real” contractor installs
it for you.

Homemade Insulation Works

Well, folks, that particular myth just ain’t true. There
may well be a bewildering selection of insulations on the
current market. And some of them definitely are more
fireproof . . . or more vermin-proof . . . or more water
resistant . . . or easier to install in new construction …
or easier to blow into old walls . . . or more this or less
that than any of the others. But when it comes to downright
cost effectiveness (even at contractor’s prices), all-around
availability, ease of installation under almost any
conditions, minimum toxicity, and absolute minimum use of
the planet’s resources in a highly “natural” way . . . the
all-time winner and champion always has, still is, and
probably always will be . . . plain ole cellulose fiber.

Yep. Cellulose fiber. Which is nothing but old newspapers,
cardboard boxes, and other kinds of waste paper . . . ground
up fine . . . and treated with some readily available and
inexpensive chemicals to make it self-extinguishing and

It’s hard to think of a more readily available, a simpler,
or a less costly insulation . . . yet the “R” factor (the
higher the “R”, the better) of each inch of
cellulose fiber is a very respectable 4. Even when you buy
it ready-made, then, this is an extremely cost-effective
insulation. And when you make it yourself your savings can
really skyrocket!

That “makin'” is not in the least complicated either. as
MOTHER’s researchers recently proved to themselves. It
mainly consists of [1] gathering together enough bone-dry
scrap cardboard or old newspapers, [2] running them through
a farm-type hammermill set for its finest possible grind,
[3] mixing in — either before or after the cellulose is
groundenough fireproofing and vermin repellent to protect
it, and [4] putting the finished insulation where you want

Use a Farm-Type Hammermill

The only “complication” we’ve found about this whole
do-it-yourself project is that nothing less than a real,
live, genuine hammermill will handle the grinding of the
cellulose the way it should be handled. Little garden
mulcher-type “shredder grinders” simply won’t chew either
paper or cardboard into the fluffy, fuzzy mass of fibers
that makes the best insulation. (Rule of thumb: If you can
still read whole words on your ground newsprint, it wasn’t
ground finely enough.)

What you want to do then (if you don’t already have one) is
rent or borrow or barter some time on one of the
feed-grinding hammermills that many farmers own (the units
are very much like the leaf grinders and limb shredders
that you frequently see utility line crews using alongside
the road).

Take care, too, to see that all the paper and cardboard you
feed through the grinder is bone dry and stays that way
(moisture can cause the shredded cellulose to “compost”).
And always wear a respirator mask to protect your lungs
from both paper dust and fine chemical particles as you

That last caution, by the way, is by no means meant to
suggest that the chemicals used to treat the cellulose are
in any way highly dangerous. Boric acid, the fire retardant
used by most manufacturers of this insulation, is — as
you probably know — so mild that doctors have
frequently prescribed it as an eyewash. This particular
fireproofer is now in such short supply, however (because
of the current tremendous demand for insulation), that
MOTHER’s research crew has tested and presently recommends
fireproofing cellulose insulation with borax. And borax, as
you’re surely aware, is so safe that it’s the major
ingredient in some laundry soaps.

The aluminum sulfate listed here as a rodent and insect
repellent can best be put into perspective when you realize
that it’s one of the chemicals generally called “alum”
(even though the term is more accurately descriptive of a
double sulfate of ammonium or a univalent metal-such as
sodium or potassium-and of a trivalent metal, such as
aluminum, iron, or chromium). The chemical, in short, is an
astringent and, as such, may be safely handled without
gloves (although we do recommend keeping its dust out of
your lungs and away from your mucous membranes). Do bear in
mind, however, that aluminum sulfate is highly corrosive to
most metals . . . and, for this reason, an equal weight of
ordinary lime (which neutralizes the alum) should be
substituted for half the aluminum sulfate when your treated
insulation will be used in metal buildings or mobile homes.

Homemade Insulation: The Price is Right

As the first chart reproduced in the Image Gallery indicates, MOTHER’s
researchers ground up and tested six batches of cellulose
fiber . . . each of which contained a different percentage of
vermin repellent and fireproofing. After trying to ignite
all the test mixes with a propane torch and observing the
results (see the chart in the Image Gallery), we recommend that a minimum of 25
pounds of aluminum sulfate (or half aluminum sulfate and
half lime) and 12 pounds of borax be mixed into every 100
pounds of ground newsprint or cardboard.

This figures out to a total chemical cost (at $8.50/100
pounds for aluminum sulfate and $15.00/100 pounds for
borax) of less than $4.00 per 100 pounds of paper that is
treated . . . or 5¢ a square foot when an attic is
filled with a 6 inch-deep layer of the cellulose fiber (which
produces a total “R” factor of 24, and that’s very good).
This compares quite favorably to the 24 1/2¢ a square
foot that a local contractor charges to fill an attic space
with only 5 inches of a commercially manufactured cellulose
fiber. On a 1,300-square-foot house, that’s an immediate
saving of $253.50 right there . . . and you’re getting
one-fifth more insulation to boot!

The chemicals were mixed into our first six test batches by
shaking them onto the paper as it was fed into our
hammermill. This is exactly the method used by the
commercial manufacturers of cellulose fiber insulation that
we’ve visited . . . but it does have a minor drawback: The
chemicals do tend to settle out of the mix as it’s handled
and, if some care isn’t taken, more of the fire retardant
than we like to see will wind up at the bottom of any space
filled with this insulation.

For this reason we tried grinding some cellulose all by
itself, putting it in a pile, and then sprinkling
controlled amounts of borax and aluminum sulfate across the
surfaces of the fiber. We were figuring, of course,
that — since flames burn up — it would take less of the
chemicals to fireproof the pulverized insulation if those
chemicals were put on top of the cellulose, instead of
being allowed to sift to its bottom.

The idea seems to have merit and our propane torch tests
indicate that approximately another one cent in chemical
costs can be shaved off every square foot of 6 inch-thick attic
insulation with no reduction in fireproofing value when
this method of distributing the borax and aluminum sulfate
is used. That increases the saving on the cellulose fiber’s
installation cost for 1,300-square-foot house from $253.50
to $266.50. Not a great additional saving, to be sure, but
one that you should know about.

Homemade Insulation Installation

MOTHER’s homemade cellulose proved just as easy — no
more and no less — to install as its commercially available
counterpart. It’s extremely easy to pour and spread around
between the joists and other structures of an attic. And
it’s just as easy to add even more later, anytime you wish.

Putting the insulation into walls and other closed spaces
is somewhat more difficult. This usually requires that a
series of holes be drilled through a house’s exterior
siding (or that some of the siding actually be removed) so
the material can be forced into the cavities with an
insulation blower. Building supply stores sometimes have
these blowers for rent . . . and some clever
do-it-yourselfers have actually forced their cellulose into
walls with a hose attached to the exhaust end of a
heavy-duty vacuum cleaner.

One final point: Any cellulose insulation — whether of
the store-bought or I-made-it-myself variety — will absorb
moisture when exposed to dampness of any kind. This, of
course, reduces the material’s “R” value . . . and cellulose
fibers should be used to insulate only those attics, walls,
crawl spaces, etc., that you know will remain dry.