You probably are referring to IBC/CBC section 2304.9.5, which does not
discriminate between the many different kinds of chemicals used for
preservative or fire-retardant treating.
Don'tcha love the building code? Some treating chemicals (borates) are
almost completely benign, and some others (ACQ, ACZA) will eat through
foundation bolts in a matter of months, according to observations by
contractors. Yet the code lumps them all into the same category. Remind me
not to buy a house built after 2004, when the new, higher-copper-content
treatments came into widespread use. More info at
www.shearwalls.com/treated_wood.html
My recommendation: Use borate-treated wood for mudsills and anything else
that will be protected from water or rain-splash. Borates do not corrode
fasteners and they don't harm mammals (in case you want to use mammals to
hold your structure together ;-)
There's also the exception to Section 2304.9.5 that allows anything BESIDES
nails, timber rivets, screws and lags to be mechanically galvanized. I
assume that this permits bolts, all-thread, and apparantly
hangers/clips/straps/tie-downs etc. to be mechanically galvanized instead of
HDG (note that electroplated is NOT the same as mechanically galvanized).
But from the reports I hear from contractors in the field, I would only
recommend HDG unless using borate-treated wood, and Stainless Steel for the
more aggressive chemicals. Simpson's website and catalog also have some
good information and recommendations.
Good luck--
Thor Matteson, SE
www.shearwalls.com
> From: PFFEI@aol.com
> Subject: galvanized vs electroplate
>
> the building code specifically requires hot dip galvanized wherever metal
> is in contact with pressure treated framing. city of LA plan includes
> this
> in plan check correction sheets and requires it to be written onto plans.
> in practical application, suppliers do not seem to be changing stock to
> hot dip galvanized for rods and hangers (hot dip galvanized nails seem to
> be
> readily available). we have contacted a couple of suppliers and they do
> not stocking hot dip galvanized rods and Simpson hangers in hot dip
> galvanized are a special order.
>
> i am curious how others are handling this issue. is electroplated steel
> (readily available) sufficient for rods and is the standard Simpson
> coating
> (galvanized G90) adequate for hangers?
>
> thank you for your comments.
>
> sincerely,
>
> paul franceschi, s.e.
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