On Fri, 04 Jan 2013 22:06:13 -0600, wrote:

On Fri, 4 Jan 2013 02:14:04 -0800 (PST), harry
wrote:

On Jan 3, 5:21*pm, wrote:
While searching the web for truss related things, I found this article
(PDF). *I was not aware of this problem, but it makes sense. *These
trusses are used in most large barns these days. *What is happening is
the moisture from animals, and ammonia from the manure is building up on
the truss plate connectors and causing them to corrode. *This could
cause the building to collapse. *I thought I'd share the article.

http://www.omafra.gov.on.ca/english/...cts/10-071.pdf

Well if you have a problem, get up there and give a dose of WD40 once
a year or so.

WD40 only lasts a few days at most. If I was going to use anything, I'd
probably coat them with tar. Melted parafin wax would probably work
well too, and not be as ugly as tar. What also comes to mind would be a
spray paint that would protect the metal as well as the wood, but it
would have to be a paint that adheres to galvanized metal. Ideally, the
truss plates should be painted on *both* sides BEFORE they are
installed.

Ideally the truss plates would be hot dip galvanized, and the wood
treated with a non-metallic preservative - like blue-wood, or an oil
preservative, such as linseed.