While papercrete is not too heavy, that weight varies with the amount of mineral content. With no sand or any other minerals other than portland cement, you can expect 20# per cubic foot, more or less. That would give you a roof load of 40# per square foot at 2' thick, so you want your framing to be strong enough for that and your snow load, plus a safety factor. If you add heavy minerals then you would need to allow for the additional weight.
You also want to get such a thick roof sealed quickly, after keeping it covered while it dries. I had a mostly flat roof 24" thick and we got an unusual rain before I could seal it. My framing was not designed to hold both the papercrete and the absorbed water, and it came down with a crash after a few hours of heavy rain. Since pc absorbs water like a sponge, even a sloped roof would have probably done the same thing. I'm grateful that nobody was under that roof when it collapsed.
From: spaceman <Spaceman@starship-enterprises.net>
Subject: Re: [papercreters] Re: just wondering
To: papercreters@yahoogroups.com
Date: Sunday, February 17, 2013, 9:01 PM
With papercrete generally running in the range of R2.5-R3 per inch of thickness, just take your desired R factor and divide by 2.5. Wall thickness would be different in Mississippi vs Montana. Of course you can always go for super insulation. I'm in an area where R18 is recommended but I make walls 12" thick for about R36.
spaceman
On 2/16/2013 9:11 PM, seniorfinancialplanningins wrote:
I live in the northern MS area, just wondering...how thick do the walls need to be?
From: eo greensticks <eogreensticks@gmail.com>
To: papercreters@yahoogroups.com
Sent: Tuesday, February 12, 2013 3:50 AM
Subject: Re: [papercreters] Re: just wondering
i am applying papercrete to a chicken wire structure. MgO on its own could possibly be blown from
a shop vac altho i wouldn't have a clue how one would go about this- but once you add the phosphate,
IF the right proportions of teh right materials are used, the chances of it setting up and ruining the shop vac are
large. those Argonne guys had a mix 'flash set'- what made it do this wasn;t clear though- it is a quick window
of opportunity- even with borax at 16% by weight the working time is only about a half an hour from memory.
Paint roller i have not tried-i think it still would only get the surface and not the under layers of wire (minimum 3 layers) same as the
brush.. I like the idea that leaving the wire out to oxidize but i am not sure how i will know when it has done this?
I started today on a new sculpture, using standard ferrocement, 3 to 1 sand to white portland with bondcrete in-
i will put paper pulp in the mix when i get above the ' splash line'- papercrete is SO much nicer to work with and easier to sculpt-.less like making 'sand castles' !On Tue, Feb 12, 2013 at 12:16 AM, JayH <slurryguy@yahoo.com> wrote:If I were wanting to paint or coat chicken wire with a liquid coating, I would think it would be pretty difficult to beat the simple technology of a paint roller.
Sometimes keeping it simple is the best most efficient solution.--- In mailto:papercreters%40yahoogroups.com, eo greensticks wrote: > > Hi, > > i have tried using spray paint to coat the armature prior to concreting but > not hugely successful- >No virus found in this message.
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