Big things happened at the job site this month. First of all, Dr. Rust came into town from San Miguel de Allende, and schooled us on how to rust metal proper.
He had a few tricks up his sleeve: bleach, muriatic acid, and degreaser. After trying a few different combinations and techniques, we ended up cleaning all 2700 square feet of 22-gauge sheet metal with muriatic acid, and then watering the sheets to encourage the rusting process.
Note: If you clean metal first with degreaser, then muriatic acid, and then spray it with bleach, it immediately creates uniform orange rust. If you skip the first and the last step, you get a lot more variation in the rust, which I personally like, and it cuts down on a lot of time and breathing of harsh chemicals. Both methods require gloves, respirators, and full clothing.
Roof – Prep
We had to tie up a couple of loose ends before starting on the roofing, namely, the canales, the crickets, and wood trim.
Canales, known everywhere else as scuppers, are a means of draining water from a flat roof. Typically in Northern New Mexico, canales are made out of wood, and sheathed in sheet metal, but we opted for 8 inch raw steel tubing, welded onto a flange (which is attached to the roof decking). We hired the Vigils (local steel fabricators) to make these for us.
Crickets are like mini roofs, mirroring the pitch of the main roof; designed to divert water away from corners and towards the scuppers.
Lastly, We had the carpenters nail 1×2 around the entire perimeter of the sloped roof, so that the plaster stop and the metal flashing would align nicely.
Roof – Installation
Nestor and Michael Martinez (father and son) are the roofing contractors that my dad has worked with for years. After we were done with all the prep work, Nestor and Michael began working on the roofs. We have a few different roof conditions on this project, so we used two different systems; brai on the flat roofs and metal on the sloped roofs.
Brai is the most common and affordable roofing material. It is also known as modified bitumen or torch-down. The first step in preparing for a torch-down roof is a layer of nonflammable felt paper, attached to the deck with roofing nails. The second layer is the waterproofing membrane, which is heated with the torch as it is unrolled, thus fusing it to the base sheet and the overlapping seam of the adjacent strip. There is some fire-hazard when applying this type of roof, but Nestor is an old pro and knows the exact temperature to heat the material, without burning the under-layer or anything around it. It is hot, messy, and smelly work, not for the faint-of-heart. Nestor and Michael next applied a coat of reflective paint to deter heat absorption. The two flat roofs were small, so it took them no time at all.
On the sloped roofs, we first applied a layer of Wind and Water Shield. It is a 40 mil (.04 inches), self-adhering, waterproofing underlayment, made of a non-slip plastic film backed with asphalt adhesive. We applied this everywhere that would eventually be clad in metal.
We were then ready to begin installing the metal roofing. The tricky thing about metal roofing is that it shows all the deficiencies in the framing, so the roofer has to visually correct anything that isn’t square in the framing. Some areas of the roof were out of square, but once again, Nestor proved his worth.
The first sheet is always the most telling. Also, the sheets were very heavy, so Nestor and Michael hired on Loya for additional man power.
22-guage metal is very thick, thus difficult to cut, so we ordered all the sheets factory cut, to specific lengths. We didn’t get the lengths quite right, so Michael ended up cutting off anywhere from an inch to two feet from every sheet. Ouch. On the bright side, Michael is now invincible when it comes to cutting metal.
Each sheet is 36 inches wide, and overlaps the next sheet by 6 inches. The sheets are attached with gasketed roofing screws, painted brown to match the rust. Before screwing the sheets down, a screw pattern had to be established, and then lines drawn every two feet to demarcate the screw location.
Inevitably there will be holes in a roof, for vent, pipes, etc. To waterproof these perforations we used roof jacks. There are metal roof jacks and there are rubber roof jacks. For the plumbing vents we used rubber, which we will later paint to match the roof. Rubber is much easier to form around the ridge profiles, but much less attractive. For the chimney we used the same black metal as the chimney pipe. In order to waterproof the chimney jack the top part has to be inserted under the roofing material, and the bottom has to be laid over. This way when water runs down the roof it will always flow over the material.
At the high side of all sloped roofs we placed a rubber closure strip that prevents bugs and water from blowing under the roofing material. The ridge cap is the screwed on top.
Note: The Company that we ordered the material from is based out of Colorado, so we had the material delivered to the project. The delivery was on a Saturday and I was there to receive the material, but I did not check to make sure that everything was accounted for. ALWAYS check. It turned out that we were three sheets short and had to wait an extra two weeks to get the last three sheets delivered. It didn’t alter our schedule drastically, but it was a painful lesson to learn.
Roof – Details
All metal roofs require flashing, custom shaped pieces of metal, which cover all raw edges and help to waterproof. They generally come in 10-foot lengths. It is used around windows, at the top and bottom of the roof pitch, and along the sides. The same people that we ordered the roofing material from provided the flashing pieces. This is the drawing that we sent them, which describes all the different profiles needed to complete the roofing part of the project.
J channel was the profile used around doors and windows. It is a very common shape so we only had to designate the amount that we would need. Using this type of material was a first for both my dad and Nestor, but I think they were pleased with how well it turned out.
In Northern New Mexico snow load is a design consideration, and because we do not have any roof overhangs, there was some concern with the snow sliding off the pitched roof, hitting the ground, and breaking a window. The solution: Snow Dogs – angle iron, installed on the low side of the roof to prevent the snow from sliding off.
Again, because there are no roof overhangs, any water that slides off the roof eventually runs down the wall. And because we are doing a rusted metal roof, along with water comes rust, which stains the wall. This was an issue unaccounted for, and so our work-around is to install gutters, with the same rusted finish as the roof, in the hopes of minimizing their presence. I will keep you abreast of how that turns out.
Can you guess what we have been working on lately? Hint: you no longer see any framing. Excititng!!!