Species of Preservative Treated Lumber 3

[BSVBD]

I sent an inquiry to awc.org, but, I have no idea when they will reply.

What species of wood is used for preservative treated lumber?

I understand that not all, if MANY at all, can receive the preservative treatment.

I've been told many years ago that only SYP can receive preservative treatment. Therefore, that is what I have been specifying for over a decade. I just want to make a follow-up after many years to see fi anything has changed.

Any thoughts?

Thank you!

 

[XR250]

Around me (central NC) it is mixed SYP last time I checked.

 

[txeng91]

Not sure if there is a limit to what can be treated but I believe SYP, which is what I usually spec for everything, is treated without incising so no strength reduction is required.

 

[SlideRuleEra]

Treatability of Major North American Softwoods

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[JAE]

Southern Pine in my area.

Check out Eng-Tips Forum's Policies here:
faq731-376

 

[OldBldgGuy]

In Ontario (& I think Canada generally) SPF is the grade group used and permitted for PT wood. That's a structural grading group (Google it if you don't know what that is) that includes species that perform comparably for structure and are virtually indistinguishable once cut into lumber. The primary component of that group in actual commercial production is white spruce, but jack pine, lodgepole pine, and balsam fir are important. The problem is that spruces don't treat well and have low retention rates, whereas pines treat very well. You guys in the states getting SYP are spoiled: great structural qualities and takes treatment like it was invented for it. Here, unless you specify that you want ground contact which requires a higher standard, if you say pressure treated it is really a crap shoot what you will get. It's not really the producer's fault, the problem really originates in the bush: once the log is cut & limbed, it's anonymous for species & they are cutting for species group. That's what they get paid for.

 

[txeng91]

I feel your pain oldbldgguy, I've had builders request SPF after I've already designed everything and it sucks. The strength and stiffness is garbage and you really take s hit on the connections with the reduced specific gravity. But from what I hear they come out a lot straighter than SYP boards.

 

[dik]

OBG:

SRE's posted a link from the Canadian Wood Council that outlines the products that should be used.

Dik