[Greenbuilding] Charring wood (was Nansulate Insulation)

[natural building]

Charring wood to preserve it - or other materials that come into  
contact with it - is a very old tradition. It can be seen -  
accidentally - in old timber framed buildings which survive fires  
because the beams and posts form a protective layer of carbon which  
retards incineration during a fire. A definite advantage of larger  
timbers over current 2x systems.

It was also used by coach-builders when working with Oak and other  
caustic woods. Surfaces that would come into contact with ferrous  
metals were deliberated scorched in order to create an inert layer and  
protect iron from the corrosive effects of tannic acid in the wood.

Regards,
Steve Satow

www.naturalbuildingsite.net
naturalbuilding at shaw.ca

On 23-Jan-11, at 8:27 AM, Benjamin Pratt wrote:

> the floor joists of my 1929 house have a charred appearance. at first
> i thought this may be evidence from a house fire, but I've since
> decided that they have always been that way. Was it a technique to
> preserve them?
> Ben
>
> On Sun, Jan 23, 2011 at 10:16 AM, JOHN SALMEN <terrain at shaw.ca> wrote:
>> When I was a kid I made money dismantling barns for the barnboard. I
>> remember it as old and tough - but relatively 'woodlike' beyond the  
>> scoured
>> surface.
>>
>> Wood on average loses about a 1/4" a century - depends on density  
>> less for
>> hardwoods, more for softwoods. Initial weathering robs the surface of
>> various lignins leaving a relatively pure cellulose covering that  
>> is highly
>> uv resistant.
>>
>> There are historical techniques of accelerating that process and  
>> creating an
>> even colouring for wood. Shou-sugi-ban is a Japanese technique of  
>> burning
>> (charring) the surface of the wood and polishing it. It is quite  
>> beautiful.
>> There are contemporary finishes that simply oxidize the surface to  
>> an even
>> grey (lifetime?).
>>
>> The problem with shakes and shingles is that they typically require  
>> 1st
>> growth softwood material with fine grain structure. These are the  
>> forests we
>> are trying to preserve locally. They are also hard to reuse (other  
>> than as
>> kindling). I don't mind 2nd growth siding untreated(used as part of  
>> a 100
>> mile diet)as it does have a long life. I prefer board and batten  
>> but current
>> rainscreen code requirements make this difficult to do.
>>
>> Best
>> John
>>
>>
>>
>> JOHN SALMEN ENVIRONMENTAL DESIGN
>> 4465 UPHILL RD,. DUNCAN, B.C.  CANADA, V9L 6M7
>> PH 250 748 7672 FAX 250 748 7612 CELL 250 246 8541
>> terrain at shaw.ca
>>
>>
>> -----Original Message-----
>> From: greenbuilding-bounces at lists.bioenergylists.org
>> [mailto:greenbuilding-bounces at lists.bioenergylists.org] On Behalf Of
>> bill.allen at verizon.net
>> Sent: January 23, 2011 5:07 AM
>> To: Green Building
>> Subject: Re: [Greenbuilding] Nansulate Insulation
>>
>> John,
>>
>> I applaud your efforts.
>>
>> My uneducated question is: Why use paint at all? Don't well  
>> installed, bare
>> wood shingles last a pretty long time (as siding) if you use the  
>> right
>> species?
>>
>> I am making these choices now for my own house and keep gravitating  
>> toward
>> natural wood (shingles or siding). With the correct roof overhang  
>> (eves and
>> gables), don't they last a while?  I just dismantled a 150+ year  
>> old barn in
>> climate zone 6 with the original, naked hemlock siding (vertical).  
>> It's got
>> plenty of life left.
>>
>> Would love any comments...
>>
>> Bill
>> -----Original Message-----
>> From: "JOHN SALMEN" <terrain at shaw.ca>
>> Sender: greenbuilding-bounces at lists.bioenergylists.org
>> Date: Sat, 22 Jan 2011 12:36:32
>> To: 'Green Building'<greenbuilding at lists.bioenergylists.org>
>> Reply-to: Green Building <greenbuilding at lists.bioenergylists.org>
>> Subject: Re: [Greenbuilding] Nansulate Insulation
>>
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>
>
>
> -- 
>
>
> b e n j a m i n p r a t t
>
> professor art+design
> the university of wisconsin stout
>
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