I know that steel studs have several advantages over wood for residential construction. So what’s the downside?
Which is better environmentally?
Peace,
mangeorge
Teach your kids to bungee jump.
One them might have to cross a bridge someday.
The main disadvantage seems to be unfamiliarity. A lot of skillful carpenters have an attachment to using wood (or what passes for lumber these days anyway). The contractors that do most of the light-gauge steel work have become familiar with it in the context of commercial buildings that don’t present many challenges to the framer’s skill. Of course, there are a growing number of glaring exceptions, I’m sure.
Light-gauge steel members also have the disadvantage of being less versatile when a framer does need to adapt to unusual conditions. The fabricator’s system is ever-changing to accommodate odd connections, but for things like radiused rafters and stair stringers, you can’t just cut up a steel joist.
Typically, light-gauge steel framed buildings I’ve seen feel flimsier. This is probably a function of using the minimum pieces to carry the design loads without considering the less tangible reassurances that buildings give. In comparison to a wood stud wall, the wallboard typically spans a greater spacing with fewer anchor points. There are means of increasing rigidity that can be used, but, again because it’s considered a cost-efficient system, extras are rarely included.
So, there aren’t a whole lot of uncorrectable problems with the system now, and most of the remainder is well within the scope of what can be easily addressed as more framers become attuned to the better materials and methods.
That said, I find it to be a fundamentally bastardized system. It irrationally casts steel into a vocabulary of wood with the idea that it’s easier to re-engineer the material than to retrain the building industry. (Which is an unavoidable reality)
A more elegant alternative to ‘traditional’ light wood framing would be to use steel in a way that plays up it’s strengths as a material. The problem is that then you are dealing with an entirely different set of erectors who are completely unfamiliar with the residential and small commercial market. (Except for the most artless prefab buildings) so this idea is still reserved for projects with a great deal of design and coordination supervision.
As to your second question, I’d believe that the building lumber industry and the light-guage steel industry are roughly equal in net environmental damage per square foot of new construction once you consider the many factors from extraction to production to transport to installation to service life to recycling to decomposition.
In the big picture, steel has many benefits as a structural material which are only somewhat mitigated by the untoward system that allows it to be a contender for house framing.
If you want to watch the real debate, tune into the North American Steel Framing Alliance at http://www.steelframingalliance.com and
the American Wood Council at http://www.awc.org
Additionally, the ecological question has been taken on in depth by Environmental Building News and in a paper published by the Canadian Wood Council. I just found these and haven’t amended my ill-informed prejudices above. http://www.ebuild.com/Archives/Features/Steel_vs_Wood/Steel_vs_Wood.html
http://www.cwc.ca/english/publications/technical_bulletins/technical_bulletin_2.html
I would think steel provides a better path for heat conduction…
Aside from the fact that steel is a better conductor of heat (and cold), and thus would require more insulation, you also have to take into account the expansion factor of unlike materials (remember the aluminum wiring fiasco in the 80’s). I also seem to recall a problem that NASA had with expansion and contraction when crossing from the sunlit side of earth to the dark side(Help with facts?). Wood-to-metal connections will eventually work loose.
Something else to consider is the do-it-yourselfer, it’s much easier to go to Lowes and get 2x4’s than to have a machine shop custom cut I-beams. And finally, when you want to put up a shelf or hang a picture, It’s a lot easier to find a stud and drive a nail than it is to drill and tap a beam to accept a bolt.
After reading my last reply, I need to make a correction. As far as heat and cold, I do realize that cold as such does not exist…cold is only an absence of heat (my apoligies to the refrigeration techs), Also I am not a carpenter… I am an industrial maintenance tech. in the sheet metal industry. I don’t build houses and I only speak from my experience. I bow to the opinion of those who have actually joined wood and metal.
Rust, weight & firmness. Try to hit a nail into a steel post when you hang something heavy.
…And then there’s the termite issue.
Formosan termites have a solid foothold in New Orleans and are expanding their range. They have utterly wrecked many of the homes in the French Quarter from the inside out.
These suckers don’t attack your home from underground (in the manner of typical termites); they fly in. Standard termite prevention plans, which rely on underground baiting systems, don’t work against them. You’ll find that most termite contracts exclude Formosan termites, because the pest control industry knows they can’t prevent infestations.
What happens when these critters expand their territory into your neighborhood? Seems to me that using steel in construction of your home might be some pretty good preventative medicine.
I would like to see more homes built with steel frames. Steel frames are better than wood frames because steel frames are better at blocking aliens’ thought rays.
[this post is available in special format for the Sarcasm Impaired–see the Straight Dope Home Page.]
“Why, sometimes I’ve believed as many as six impossible things before breakfast!” - the White Queen
A distinction to keep in mind:
Light guage steel framing uses standard bent sheet metal pieces and self-tapping screws in a system very similar to conventional western platform wood construction. This is different than heavy steel framing which is put together out of rolled steel shapes which require specialized fabrication and erection tolerances and turn back all your picture hanging nails.
I’m not sure how much the conductivity of light guage steel studs affects the R-value of a typical exterior wall. But I doubt there would be much of a difference - the studs aren’t usually the weak point in insulative effectiveness. Sound transmission is another ball-game though.
One thing I did not mention earlier is that you have to run all the wiring in conduit so that the sharp edges of the studs’ pass-through holes don’t damage the insulation on the wire. I think some places allow pop-in plastic collars in lieu if conduit. These are probably cheaper to put in than the drilled holes required in wood studs.
Hey, what happens when they get hit by lightning? Whoa, what a display!