Friday, July 11, 2008

Re: [papercreters] Re: new project help

My battery dome was 1' thick pour with 6x6x10 and diamond lath on both sides to hold the paper in. It worked well for me. I mixed and pumped for about two weeks for my little 10' diameter dome. I think the effort I put into getting a tight framework to pump papercrete into helped me avoid the enormous cracking that others have seen. Lath is your friend!

Lots of people on the list have done slip form based pours. You won't have to spend nearly as much on steel as I did. The drawbacks I see to slip forming are:

1. long delays for drying
2. two person effort for pulling bolts and raising form height
3. sloppy looking finished wall (this can be cleaned up with stucco's or plaster)
4. large amount of material for forms (might be able to rent from concrete shops)

I do think there is a lot of promise for someone to work out a great slip forming technique for papercrete. It sure beats all the steps required to do block work. If you can afford the steel (rebar, remesh, lath) I recommend going that way. Reduce your risk of cracking and structural problems to get the exact shape and strength you want.

On Jul 11, 2008, at 2:15 PM, dad8now wrote:

Dad8 may be looking to pour everything in one large pour. At least a
large pour between each set of posts. Mikey Sklar has proven with
his Battery Room that large monolithic pours can be accomplished

yes a monolithic pour between poles is what I wanted to do.

however slip form might be more practical ?????

Would love to hear more about Mikey Sklar success with this..

--- In, "slurryguy" <slurryguy@...> wrote:

Symantics, shmantics.

I thought Dad8's use of the term "Pole Barn" was perfectly 
acceptable.  I never got the impression that he was describing the 
function of the structure with that term, but using it to create a 
mental image of the style of contstuction that was being used to hold 
up the roof.  Also, many people have converted Barn structures into a 
home.  Common practice is still to call those structures barns, even 
though the only animals inside are human (and maybe a canine or 
feline or two.)

There are significant differences in the manner of construction of a 
Pole Barn and a Timber Frame.  

While the exact technical definition of Timber Frame construction 
only indicates the use of strutural wood posts and beams, it commonly 
implies an extensive use of impressive mortice and tenon joinery, 
those really awesome scarf joints, and wooden pegs holding a lot 
things together.  When done well, the structural timbers can be more 
than engineering support, but a wonderful work of art in themselves 
at the same time.  When I think of timberframe, I think of the 
carpentry, not just some poles and a simple roof.

A pole barn is simply a bunch of posts (of whatever material) holding 
up a roof.  It implies none of the fancy old school carpentry.  I 
think this is what Dad8 intended to convey.

I thought Dad8's first post to this group was an excellent effort, 
and he should not be concerned about getting into a semantic argument 
about the exact technical meaning of words.  He conveyed his meaning 
very well.

"Slipforming" is by definition done in stages as Neal describes.  
Pour a layer.  Wait for the layer to set.  "Slip" the forms up.  Pour 
another layer. Repeat as needed.

Dad8 may be looking to pour everything in one large pour.  At least a 
large pour between each set of posts.  Mikey Sklar has proven with 
his Battery Room that large monolithic pours can be accomplished 

Tim Pye's experience with large pours had lots of problems (huge 

Both slipforming and large monolithic pours are viable techniques to 
use, but only when done properly.  Compressing the papercrete within 
an hour after the pour helps drastically with either method.  The 
forms must be built strong enough to withstand the compression 
process without blowing out.

--- In, sire@ wrote:

In the spirit of Slurryguy's admonition to help others, I'll add a 
few comments to his excellent commentary on dad's questions.    I 
admire someone who is able to itemize his questions and logically 
address the various aspects of the project.   However, coming from 
someone who has read about papercrete till his eyes hurt, it seems to 
indicate that the general public has quite a few misconceptions about 
what papercrete is and how to use it in construction.   There are 
others in this group more qualified to comment on this project than I 
am, but hopefully I will reinforce the points that SG made and add a 
few thoughts from my own understanding.

Dad, when you say you are building a "pole barn", I thought this 
would literally be a barn, but it turns out that it will be a 
dwelling, more like a getaway cabin for your wife and kids (without 
you?).   Getaway places are usually for the summer, but the mention 
of wood heat implies winter use also, so perhaps this will be a year-
round second home?   The structure seems to be basically a 
timberframe with papercrete infill.   

Latex on the inside is optional but not necessary.   Latex on the 
outside would be far more beneficial almost required a part of the 
waterproofing.   As SG writes, borax or boric acid would best be 
applied in a way that it would not drain away with the excess water, 
perhaps a spray coat on the outside after the walls have dried.   
Borax is commonly used in laundry and boric acid in the garden, so 
this will not be a danger to the boys unless they are eating the 
papercrete for dinner.  :)

Slipforming the walls and pouring them up to 8' would be fine, but 
it must be done in stages, as slipforming implies, probably 2' at a 
time.   You will have to wait at least a few days between courses for 
drying.   Like adobe, stawbale, cob, etc., papercrete walls should be 
thick.   I would say they should probably be at least 1' thick in 
order to provide insulation and stability.   Thick walls will also 
make unnecessary any reinforcement in the walls, which SG has already 
mentioned would be problematic anyway with papercrete shrinking away 
from metal.   Do not make the plywood forms waterproof and remove 
them as quickly as feasible to allow the walls to dry out as quickly 
as possible.

We have recently discussed again the advantages of papercrete as a 
floor, but if it is necessary to have this structure "just above the 
ground", this may not be practical.   In any case I do not see the 
reason you are thinking of using a plastic liner when pouring the 
papercrete floor, nor can I imagine why you would want to cover the 
floor with plywood because that seems unnecessary.

There are very many reasons not to attempt a papercrete roof.   
Perhaps now you can intuit some of them, but if not they could be 
detailed in a separate post if desired.


-------------- Original message -------------- 
From: "dad8now" <mark_bal_christian@> 
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 

The floor will be just above ground with skirting around the 

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 

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 
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 

thanks for this group,



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