[Greenbuilding] Charring wood (was Nansulate Insulation)

[JOHN SALMEN]

Basically it does - as I mentioned wood deterioration (weathering) is a
surface phenomenon. UV and moisture degrade the lignin on the surface of the
wood leaving cellulose which is resistant to subsequent UV degradation.
Removing that layer (which is pretty thin .1-.25 mm) then exposes a fresh
layer which then degrades to cellulose again as it is exposed. If you clean
the cellulose layer off the surface then you really need to put a UV
resistant finish on - if you leave it grey then really all you have to
contend with is the roughness of the wood and the comfort of the furniture.

 

Weathering though is also progressive as when the surface degrades it
becomes friable, splinters, loses fibres etc. This traps moisture and dirt
which then swells the wood - opening up more area for weathering. Since
cellulose is a food for fungi - wood surfaces can become mildewed or moldy
if there is sufficient moisture (if the wood is continually wetted without
decent periods for drying). We are locally experiencing more intense rains
with periods of sun that is keeping exterior wood wetted for longer periods
(sun driving the moisture in).

 

 

 

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

 

  _____  

From: greenbuilding-bounces at lists.bioenergylists.org
[mailto:greenbuilding-bounces at lists.bioenergylists.org] On Behalf Of Sacie
Lambertson
Sent: January 23, 2011 10:25 AM
To: Green Building
Subject: Re: [Greenbuilding] Charring wood (was Nansulate Insulation)

 

Speaking of charring, I've often wondered as I occasionally scrub off the
accumulated gray on deck furniture if the process that results in the
graying is in an way also protective of the wood?  Any thoughts on this?
Sacie

 

Charring wood is done a lot in traditional Japanese building with a lot of
success.

 

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