The cold-rolled steel roof has oxidized nicely over the fall and winter. It looks pretty good. Most of the steel siding is starting to turn as well, but it is pretty well protected from water, and with temperatures mostly below 50F, the oxidation rate is slow. Still, I’m pretty sure that by the end of the summer, most of the steel siding will have a decent patina on it.
However, the steel panels on the front of the house are very well protected. They basically never get wet. By mid-Spring they were looking pristine. So, I decided I would accelerate the process. Here is the siding in that area before I did anything…
I mixed 1/4 muriatic acid (standard stuff at Home Depot) with 3/4 tap water in a spray bottle. (Be very careful. Muriatic acid is, well, acid. It really does burn your skin and can destroy your eyes, too. Gloves and safety glasses/goggles are essential.) I simply misted the entire wall surface with the spray bottle. In 24 hours, as long as the temperature is above about 50F, the entire surface will be very rusted. You can see where you have missed spots and just hit those again. I’ll be curious to see how the accelerated oxidation compares in color to that of the naturally oxidized surface. You can already see that where water has bounced onto the wall, the surface is more orange. Anyway, I’m pretty happy with the results. I would be curious to know if an even milder acid would work (e.g., white vinegar). I bet it would, especially if the temperatures were a bit higher.
The baseboard in this house is 1/8″ x 3″ hot-rolled steel strip. It came in 20 ft. lengths and was installed with McFeely’s washer-head combo-drive screws centered on the strip. The finish carpenters did it. They were curious if not skeptical initially. By the end, they loved this stuff. There is only one seam in the entire house (on a 25 ft. wall). It went up easily. I plan to do nothing to this. Everyone likes the way it looks too. Did I mention it is super cheap ($0.60/ft or so)?
The house will have an 8-foot-deep nearly flat roof over the terrace. It’s kind of like a store-front awning. The architects designed it to be supported by four tie rods, which gives it a cool look, and avoids using any columns to support the edge of the roof. Of course the problem is that this structure has to be designed to handle all the snow from the roof above landing on it in an avalanche. So, it’s incredibly beefy and ties into big steel columns in the walls. This feature of the house probably cost about $10,000 more than a conventional “porch roof.” Still, I can’t imagine a better use of $10,000 in giving the house a distinctive quality.
The roofers have nearly completed the steel siding on the house. I’m very happy with the results. We are using 2′ x 3′ 20 gauge cold-rolled steel flat panels. It is very inexpensive (~$2/sq-ft materials and labor), and I think it looks fantastic. It will rust to a reddish brown when exposed the weather for a few months.
When the project is completed, I’ll give a more nuanced reflection on the use of steel in residential construction. At this point, I’m pretty satisfied with the outcome, but the process was pretty painful. The short version of the process is (a) the architects create a beautiful form, (b) the structural engineers are asked to make it work, (c) they have to use lots of steel to realize the vision because of things like seismic requirements and snow loads, (d) a steel company “details” each part from what can only be characterized as a suggestive design by the structural engineers, (e) someone checks it carefully (me, in this case), (f) the steel shows up, (g) the framers integrate it into the structure, and (sometimes) (h) the welder comes out to fix mistakes on site.
We had only a few mistakes, and they were the supplier’s errors, so were fixed at no cost to me. What’s challenging about steel is all the coordination and the inability to adapt much during the process. On the other hand, the stuff is remarkably inexpensive, really strong, and looks nice when exposed (in my opinion).
In the interests of completeness, I should also add that a lot of the steel in this house is architectural in addition to structural. We are using tie rods, beams, and channels as aesthetic features. They’re really nice features, and worth the cost. I have no reservations about our use of steel in this way. My main regret is that we didn’t do a bit more creative problem solving in steps (a) through (c) to find design solutions that did not require as much hidden steel…which is expensive with no visual pay off. (The structural engineers point out that having the house survive a heavy snow fall or an earthquake is a pretty important design requirement. Agreed. But, in some cases with a bit more coordination, the architects could move a window three inches to fit two more 2x6s in the wall and thus eliminate an expensive, tricky piece of steel.)