What happens to steel studs in the rain?

[Hazen]

Silly question, but all my steel framing construction was in an extremely dry climate. I certainly replaced some rusted ones. Would the corrosion due to rain here actually make steel framing pointless here?
How long and how much rain does it take to rust a steel stud? (assuming you're not right on the ocean)

[Rob Tucker]

Steel framing is galvanized to protect against rust. I have galanized steel which has been outside in the rain for years without rusting. There are basically two types of galvanization. Hot dip process and electro-plating. The hot dip process is the more durable galvanization of the two.

When the steel is cut an ungalvanized edge is exposed to the atmosphere and this cut edge should be sprayed with a cold zinc coating.

I have seen galvanized steel damaged by acid rain from the volcano (VOG) and acid could be a problem depending on the location and an acid rain event.

[Carey]

Hazen, no great background, but I have noticed places that are building with the galv. steel studs (by you, Church on a Sure Foundation is adding a large steel stud addition, might want to check with them). The one thing I have noticed is the amount of corrosionon the steel I-beam outdoor structures (good example is HPM's outbuildings in Hilo) get. Don't know the care they have gotten, but do see the damage. We are in the same boat, trying to figure out what to support a lanai add on. Termites have made me go against any wood, there are aluminum structures, but that is really alloy dependant, seen some of that corrode here, steel...We have really started to look at the fiberglass columns at Lowes, 10,000# load bearing, a little too classic in design, but OK, and 8' lengths on island. Still contemplating, the cost is more, but I look at replacement &/or shipping anything else....
Oh, our only experience with steel studs is that Mother in law had a condo with steel studs, unit bath above hers had a leak (probably long term) that eventually corroded her walls, they literally crumbled. BUT this was long term & probably constant moisture & high humidity in the wall section, most likely would have done in most materials.
Aloha, Carey





Edited by - Carey on 09/05/2006 15:26:30

[Rob Tucker]

Most of those big metal kit buildings like you saw at HPM were not made with hot dipped galvanized steel. They are what is referred to in the trade as "red iron". They arrive on site with only a sprayed red primer on them.

If the customer adds other paint coatings that helps but many, many of them were done as cheaply as possible and the primer doesn't protect well or forever. So they rust.

I use a lot of hot dipped galvanized steel and have found that it performs nicely . The hot dip source I use on the west coast does a lot of work for the off shore oil industry and they have process' that are as good as it gets.

[Carey]

Rob, do you have a source for hot dipped galvanized I-beams? we tried at Hilo Sheet Metal & were told the red iron was about it, even tried to find out about structural Aluminum I-beams, with no response (not even what alloys were available...)
Aloha, Carey