Switching to a steel roof – part 1: Decision process

One of the items I looked for when I bought my house was that the roof was in good shape. At the time it was, but as the years progressed I found myself needing to do more and more repairs, mainly replacing broken tabs and adding proper roofing nails in places where the staples used in the original installation were backing out of the decking. When I came home one particularly windy day and found several broken tabs in the yard as well as some lifted shingles on the roof I decided that it was time for a new roof.

At my previous house the old shingles had begun to buckle and curl so I did a tear-off and re-roof myself, but it was a relatively simple roof with an easy slope. The current roof is steeper and more complicated, and having recently had a colleague fall off his roof while doing some minor repairs (luckily escaping with “only” a broken ankle and some heavy bruising) the next decision was easily made: I would not be doing this one myself.

When I think of residential roofing the image that comes to mind is asphalt / fiberglass composition shingles. Up until this house I had never really had any issues with them, and on this one the roof was around 5 – 10 years old before the staples began to back out and began loosening the shingles to the point that a strong wind would cause some of the tabs to lift and eventually break off. At first it was an occasional tab after particularly high wind, but over the next 10 years or so it became a regular occurrence to have to head up on the roof with a box of nails and a tub of roofing tar to repair the damage. It should be noted that nearly all asphalt shingles state very clearly on the instructions that staples should not be used, yet I have seen many roofing contractors using them because of the lower cost and easier handling during installation.

Any thoughts of putting new shingles directly over the old were quickly removed by the staples in the original roof; it might take a bit longer with a additional layer above, but their backing out would probably impact the new roof the same way it had the old. Although I could have had the old shingles torn off, the staples pulled, and started over with a new shingle roof properly nailed in, I decided to explore other options.

A friend who put a new roof on her house last year had wanted to go with standing seam metal roofing in order to use self-adhesive solar panels. Though she ended up not going that route due to a reliability question with the solar panels, she had done a fair amount of research on residential standing seam roofs and I began leaning that direction.

Living in a semi-rural area I am well aware of the many uses of steel panels in outbuilding construction, but I was somewhat skeptical of residential application. I needed to look no further than the barn at Rurikia to find an example of overlapped panels screwed onto wooden crosspieces as roofing, and though the exposed screws and unsealed overlaps always look like places to expect leaks my experience has been that the roof has functioned well. A big advantage of standing seam over panels is the hidden fastening system so there are no exposed screws to worry about, and I pretty much sold myself on the idea of a standing seam roof. In addition, it is lighter than a shingle roof and it’s structure is sufficiently rigid that it wouldn’t be affected by staples backing out.
After doing a bit more research I recognized that a metal roof would be a better environmental choice as well. Unlike shingles which tend to absorb heat and transfer it into the roof structure and then into the attic air, the painted metal is much more reflective so there is less heat buildup inside the house. Most steel roofing is at least partially made from recycled steel, has a longer lifespan than shingles, and both the scraps from installation and the finished roof can be fully recycled, unlike composition shingles. Although steel will rust if given a chance, the material used is fully galvanized and has a multi-stage coating process similar to that used for automotive panels. Additionally, the lower weight eases the environmental impact of transportation relative to shipping shingles.

With everything looking in favor of the standing seam roof, I called around for estimates and only found a few roofing companies which handled metal roofs. Of those, one of them stood out on several fronts – they promptly returned my calls, had meaningful conversations, and provided a competitive initial estimate including a realistic schedule. Topping off the attributes was that they were a local business; they source their steel from a recycling mill less than 200 miles away and their production facility is within 15 miles of Rurikia. In addition to all this, their production facility is fully powered by solar energy from panels mounted on the factory roof and is one of the largest suppliers of solar energy excess into the local grid.

I thought I was all set when the sales rep came out for the final estimate. I wanted a standing seam roof in light grey installed directly over the existing roof. Unfortunately for those thoughts, within 30 seconds of arriving he pointed out that I didn’t want a standing seam roof. His reasoning was simple; there was a slight slope change in the roof where the eaves were lengthened away from the house, and it was more of a slope change than standing seam could accommodate. The only option with standing seam would be to have the main part of the roof at one slope, then stop that roof and flash into a second part on the flatter bottom section. Given that the bottom section would only be around 18 inches wide, it would have visually broken up the roof into a very odd looking creation as well as increasing the open areas under flashing where wind could get hold and potentially lead to damage.

He only had to go to the back of his van for a different option I had not considered: large steel panels which had been pressed into a shape approximating heavily weathered wooden shakes. Because of the way they were made and mounted, they could easily accommodate the change in roof slope. Each panel was around 1 foot tall and 3 feet wide of 24 gages steel and consisted of several “shakes” with a deeper impression between them. They did not look like wood to my eye, but the combination made for a very stiff but light panel. Surprisingly to me, these had a higher wind resistance, higher energy efficiency rating, and as an installed roof was less expensive than standing seam. The energy efficiency came from the fact that these panels require a wooden structure to mount on top of the existing roof, and between a reflective roof liner, the airspace occasioned by the 2×2 mounting strips, and the inherent benefits of the steel it is estimated to drop attic temperatures by around 30 deg F in the middle of summer relative to a composite shingle roof.

Aesthetically I was worried about the shake profile as I was used to the pattern of shingle tab sized blocks, and the shake pattern would be a big departure, but the profile options on offer were either that or round tile, which would not fit with the house at all. To help make it look less uniform, the deep impression between each shake was sprayed black to help define a shadow line. When it came to color, the light grey I wanted was not offered as a stock color, but there were bluish grey and a brownish grey options. I couldn’t decide, so I went to the woodpile and found a piece of split wood which had weathered a bit; it was closer to the brownish grey so I opted for that color. The company did offer custom colors, but there was a substantial price increase to go that option and the stock color worked fairly well with the house. Had I been able to go with standing seam I would have probably selected the bluish grey as it was closer to the existing light grey of the shingle roof which I had no objection to, but with the shake pattern I wanted something that at least resembled wood in color as I have never seen a painted wood shake roof.

I did end up with standing seam on the porch roof as it was to flat a pitch for the shake profile to be used.

In summary, my decision to go with a steel roof was primarily based on lifespan, durability, and lower maintenance outlook over the lifespan of the roof relative to composite shingles. Improved energy efficiency and better environmental performance were important secondary considerations. The installed cost came out to be roughly twice that of a composite shingle re-roof over the existing shingles.

steel_shingles

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