[Strawbale] Oak

[Rob Tom]

On Thu, 03 May 2007 15:12:28 -0400, Lawrence Lile <LLile at projsolco.com>  
wrote:

> A guy was asking me offlist about using oak for beams cut onsite in
> houses.  I seem to remember something on the list about problems with
> beetles eating up the wood.  What about those oak log homes that
> Gastineau and others make? Is this a real problem, and how is it dealt
> with?  Is it a regional problem? Or just a wrongheaded code official
> causing trouble?

LL-man;

I'd say that how much the oak will get gobbled-up depends upon the species.

I've seen green Red Oak get turned into a mess of tunnels by plain old  
carpenter ants and I've seen the sapwood of dry White Oak turned into a  
piles of sawdust by borers.

So if "the guy" is using Red Oak, it'd probably be a good idea to  
implement measures to keep carpenter ants away from the timbers until they  
dry out and if "the guy" is using White Oak, to remove the sapwood from  
the timbers. Can't tell you anything about other types of oak or bugs.

Aside from the issue of bugs, there is the problem of the potential for  
major distortion and horrendous checks and splits if the green timbers are  
subjected to the drying conditions that are typically found in heated  
interiors in winter.

The distortions can be minimised by using joinery/framing techniques that  
adequately restrain the timbers while drying (ie a few toenails aren't  
going to do it) and by sealing all six faces (to control the rate of  
moisture loss) before the timbers are installed.

For flexural members, it's a good idea to install temporary shoring at  
midspan until the timbers have dried because when green, they are likely  
still flexible enough to sag under their own weight.

Splitting/checking can be minimised in part by the sealing mentioned  
previously (typically I choose a sunny day with good breezes and set the  
finished (ie joinery done, surfaces planed/sanded, corners beaded) timbers  
on sawhorses outside and keep slathering on successive coats linseed oil  
and then allowing them to fully dry before moving them inside. If you  
don't allow them to fully dry, the linseed oil will remain tacky forever  
and become a magnet for dust and may support mould growth )... but it also  
helps to mill in stress-relieving grooves.  When well-planned, the grooves  
can be used as wiring chases.

I would suggest that if there is any wrong-headedness involved, it's not  
on the part of building officials but rather, by wood butchers who don't  
understand the nature of the material that they're butchering.


-- 
=== * ===
Rob Tom
Kanata, Ontario, Canada
< A r c h i L o g i c  at   C h a f f Y a h o o  dot  C a  >
(winnow the chaff from my edress in your reply)