Friday, July 11, 2008

[papercreters] Re: new project help

Hello Dad8,

Welcome to the group.

Your project sounds interesting. I look forward to reading more
posts from you as your project progresses. I have several thoughts
for you.

Boric Acid:

Borax is a lot easier to work with in papercrete slurry than Boric
Acid. Several members have had good success using good old laundry
borax. I cannot find one documented success story of someone using
Boric Acid in Papercrete and liking the results. (I encourage
someone to post a Boric Acid/Papercrete success story if they have or
know of one. Heck, feel free to post an unsuccessful Boric Acid
story. I'd like to learn about either story.)

My opinion about Boric Acid is that maybe past attempts have used it
incorrectly. Past attempts that I'm aware of have involved adding
the acid in the wet papercrete mix. I theorize that a significant
amount of the Boric Acid drains out of the papercrete and therefore
doesn't stay inside the material where it can do any good.

If someone is determined to use Boric Acid, I wonder if a better way
to use it would be to create a dilute solution and spray it over the
surface of DRY papercrete and allow it to soak in. To my knowledge,
THIS IDEA IS COMPLETELY UNTESTED WITH PAPERCRETE. Logically, it
should be effective, but I offer no guarantees. I also think that it
might be a reasonable way to treat existing papercrete already inside
a structure that may be having mold or insect problems. (Keep in
mind that the first actions for mold in papercrete is to KEEP IT
DRY. No amount of Borax or Boric Acid is a substitute for proper
building practices and keeping the papercrete DRY!.)

I don't have any hard data, but I suspect that Boric Acid is
significantly less effective as a fire suppressant than Borax is.

I encourage you to mix up a bucket or two of papercrete and
experiment with no borate additives, Borax, and Boric Acid using
various techniques and see what performs best under the conditions
you expect to have.

Of course, please post to the group about what you do and what you
learn.

Natural?

You commented that you wanted to use latex on the interior and leave
the outside, "natural."

Are you saying that you want to leave the exterior papercrete exposed
to the weather? If so, this is NOT a good idea. Papercrete is a
wood product, made from wood fibers. It needs to be protected.

Your specific questions:

1) Will chicken wire fastened in the center of the 6" beams be
enough reinforcement since the walls bare no weight? Or should I add
vertical rebar every 2 ft??

No. I do not recommend trying to reinforce papercrete by attempting
to embed metal inside it.

A far better use of the chicken wire would be to embed it into a
surface ferro-cement layer or stucco finish. Have you considered
using something like chicken wire as part of a permeable formwork
that can be left in place? It could take the place of your plywood.
You could easily plaster or stucco over it. Your 6" thick walls are
rather thin for papercrete. Papercrete has a low tensile strength,
so a reinforcement strategy will probably be very imporant to keep
the papercrete from wanting to bow in or out. My suggestion is to
try various ideas on a test on a small area and see for yourself what
makes sense.

Using rebar reinforcement in a surface layer of chicken wire may be
helpful. Don't try to embed rebar inside wet papercrete and expect
it to stiffen the wall. This has been attempted previously. As the
papercrete dries it tends to shrink, and it will shrink away from
objects embeded inside it, like rebar. The rebar won't be of much
value if it is rattling around loose in a papercrete cavity.

3) How many days should I leave the plywood forms on to minimize
shrinking until walls cure?
and
4) Would making the forms watertight prevent shrinking until
cured 5 days and then remove the forms?


Papercrete shrinks. Get used to it. Playing games with keeping
papercrete wet is going down the wrong path. It's asking for
problems. Shift your thinking to be able to adapt and work
around/with the shrink once it happens. The length of time the
formwork is left in place will not have any significant impact upon
the amount the papercrete shrinks when it is finally dry. (and you
must get papercrete completely dry)

The best method I've found to minimize shrinkage is to wear insulated
underwear in cold weather. (hehehehe. Sorry, I've been entirely too
serious through most of this post. I had to toss a joke in there
somewhere. Okay everyone, keep it clean. This group is rated "G".)

There are several factors that determine how much papercrete
shrinks. Higher paper content recipes tend to shrink more. If the
drained, but still damp slurry is compressed, this will significantly
reduce shrinkage. The better it is compressed, the less it will
shrink. There is a point of diminishing returns.

If your experiments demonstrate an unacceptable amount of shrink
incorporating the above tactics, the next step is to alter your
forming system. You can adjust your forms to be larger than what you
want the final papercrete size to be and allow the papercrete to
shrink down to the desired final size.

Another possibility is to add more papercrete to fill in the gaps
after the first round of papercrete dries and shrinks down.

How long you leave any temporary formwork in place will be determined
by how long it takes for your papercrete to be self supporting. Once
the formwork is no longer needed for support, it can be removed to
speed the drying process along. (don't let papercrete sit around wet
longer than necessary.)

5) What R factor would this wall recipe probably have?

There's not enough data available yet to predict accurately. The
amount the damp slurry is compressed can vary this number to a large
degree. Assuming minimal compression, I would guess that recipe
looks like about an R3 per inch mix. YMMV. Compressing the damp
slurry will IMPROVE the R factor. (paper is NOT fiberglass) With a
few hundred lbs/sqin damp slurry compression this might climb close
to the R4 per inch range. This does not factor in the posts or other
materials that will be included in your wall structure.

6) Could I attach 6mil plastic liner to inside all around the
walls down to he ground and then use this same PC recipe as a
subfloor and then cover with ½ plywood?

This depends. Are you planning on pouring wet papercrete on top of
this plastic? If that is your intent, I offer my strongest words of
warning available. I do not recommend this procedure. Wet
papercrete needs to drain away its excess water. The plastic will
trap it in place. The papercrete would take a very long time to dry
and this is always asking for trouble. Mold would probably grow on
the bottom of the papercrete next to the plastic. The mold might not
be visible there, and you wouldn't know about it. I know I wouldn't
want to expose my family to that.

On the other hand, if you plan on placing DRY papercrete blocks or
portable slabs on top of the plastic, this may be an excellent idea.
If the area under the plastic is a moisture rich environment, the
vapor barrier makes a lot of sense.

Yes, plywood can be placed on top of papercrete if you choose. Glue
will be a better fastener for the plywood than nails.

Have you considered a papercrete floor?


7) Would a 6" thick PC 2/12 pitch roof need to be waterproofed
or left natural? Or water proofed with marine grade polyurethane
varnish?

In a Missouri forest?? You bet it needs to be waterproofed.
Papercrete will act like a sponge and soak up water. It can absorb
many tons of weight in just one rain. An untreated papercrete roof
is dangerous. KEEP PAPERCRETE DRY

ALWAYS KEEP IT DRY.

I can't say it enough. KEEP IT DRY!

I do not recommend using a varnished papercrete roof. Shingles or
metal roofing make a LOT more sense. Shingles are inherintly
redundant. Don't be afraid to get creative and find an inexpensive
shingle material.

8???) thanks for this group,

dad8... the absolute best way you can offer thanks is to contribute.

Ask lots of questions.

Post frequently about your very interesting project.

Pictures? Where's your pictures man? You can at least post a
picture of the empty site where the building is going to go up.

Do you have the ability to post video clips on YouTube? We have a
group area on YouTube for our papercrete stuff.

The greatest thank-you anyone can give for this group is to give
back. Help someone else! What areas do you have experience with?
Look for someone asking a question that you can answer or provide
insight.

I'm not speaking only to Dad8 here. I'm speaking to everyone. If
you appreciate the group. Show that appreciation by trying to help
someone. You just might be surprised at how much you help yourself
in the process.

I wish you success with your project, Dad8.

Have Fun...

--- In papercreters@yahoogroups.com, "dad8now"
<mark_bal_christian@...> wrote:
>
> I am new to PC and have been reading until my eyes hurt.
>
> I have a 17 acre all forest in Missouri, with little or no building
> codes.
>
> The floor will be just above ground with skirting around the
> perimeter.
>
> I want to build a small pole barn for seasonal use using Six inch
> beams and 8 FT tall walls
>
> So my PC wall will be 6" thick and 8" tall. And 10 FT wide between
> beams
>
> There will be no load on the walls.
>
> I will latex paint the inside walls and leave the outside natural.
>
> Here is the PC recipe I'm considering using.
>
> 1 part news print (DRY) by weight
>
> 1 part Portland (DRY) by weight
>
> 1/9 of a part hydrated lime (DRY) by weight
>
> ????? boric acid for bug/ rot / fire retarding ???
>
>
> I want to pour the wall up right between the beams with removable
> forms on both sides.
>
> We will heat with wood.
>
> My wife and three small boys will be using this new get away.
>
> Here are my questions so far:
>
> 1) Will chicken wire fastened in the center of the 6" beams be
> enough reinforcement since the walls bare no weight? Or should I
add
> vertical rebar every 2 ft??
>
> 2) Do I need the boric acid? And if so how much to be effective
> but not be hazardous to my little boys?
>
> 3) How many days should I leave the plywood forms on to minimize
> shrinking until walls cure?
>
> 4) Would making the forms watertight prevent shrinking until
> cured 5 days and then remove the forms?
>
> 5) What R factor would this wall recipe probably have?
>
> 6) Could I attach 6mil plastic liner to inside all around the
> walls down to he ground and then use this same PC recipe as a
> subfloor and then cover with ½ plywood?
>
> 7) Would a 6" thick PC 2/12 pitch roof need to be waterproofed
> or left natural? Or water proofed with marine grade polyurethane
> varnish?
>
> thanks for this group,
>
> Dad8now
>

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