[Ferro List] FC-Lightweight-FC sandwich

[Walter Jeffries]

On Apr 9, 2008, at 3:29 PM, janoahsh at alaska.net wrote:
> Hi Doug and all,
> I am finally at a point to build a composit shell.  The problem is  
> which composit
> to use for the core.  Papercrete core,sawment, aireated, foamed, etc.
> I'm beginning to think foamed may be the easiest.  What I'm mostly  
> looking for is
> insulation, durability, and low cost sprayable, fire resistance.
> I'd like to know what your ,.. my best bet is.
> Last minute jitters etc.
> I,m operating away from home and not fully following this exchange  
> but will try and
> catch up today.
> Janosh

This is somewhat like we did. Last year we did a test structure, a  
dog house which you can see at the link below, and this is the same  
technique we'll use on our cottage roof which currently just has the  
inner shell of the barrel vault done. Basically two FC layers with a  
lightweight concrete layer between them. We used vermiculite/perlite  
to get our light weight concrete.

Between the beaminess of the sandwich, the FC tensile layers and the  
barrel vault it is very strong as well as offering a degree of  
insulation.

We will bury our cottage roof eventually but I was just calculating  
the other day that even exposed it would be fine because every N  
years you could just do a thin neat over coat. Our 1.5" thick FC  
cottage roof (PVA concrete + diamond lath) has now been through two  
winters with no leaking, no cracking and no spauling. I was a bit  
worried about the latter given our extreme range of temperatures.  
Perhaps the deep winter snow cover helps.

Cheers,

Walter Jeffries
Sugar Mountain Farm LLC
Orange, Vermont
Pastured Pigs & Sheep
http://SugarMtnFarm.com/blog
http://HollyGraphicArt.com
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