A steel-clad, low slope roof is a key element in our passive homes. For the essentials on low slope roofs, start here.
Why a low slope?
In a nutshell, a low slope roof uses much less material than a more traditional or complex roof style. A traditional gable roof line would use roughly 50% more material, and drive up cost accordingly.
A great example is our model home, the Pine Valley bungalow, which has 1,600 square feet of interior living space within a simple rectangular envelope. The roof for the Pine Valley bungalow covers approximately the same square footage as the home’s interior.
The slope or pitch of a roof is determined by how many inches it rises over a foot. A 4:12 pitch, which we use most frequently, will rise four inches over every 12 inches or foot of roof surface.
A passive house and a low slope roof
The passive home feature in this post, including below, is one we finished in Wakefield, Quebec in 2020.
Why we use steel for your low slope roof
We selected a steel roof from Ideal Roofing quite a few years ago and have stuck with it. Aesthetically this solution looks great, but it’s also the most environmentally friendly solution.
In North America, roughly 30% of steel manufactured each year must be made from recycled material. And, of course, at the end of your roof’s life cycle, the steel can again be recycled.
The longevity is another big selling point, with a steel roof lasting upwards of 50 years (Ideal Roofing has a limited warranty for 40 years), compared to 15 or 20 for an asphalt shingle roof.
Stick with us – we get into snow loads in the next section, including our approach to handling these.
Heritage and Junior H-F Options
We tend to use the Heritage and Junior H-F roof options from Ideal Roofing.
The 4:12 roof slope that we use most frequently has to make use of a roof system with a low profile “standing seam” and no exposed fasteners or screws. We use the Junior Heritage for this; it’s the most cost effective.
When a client wants an even lower slope, we turn to the Ideal Heritage 1.5″ thicker standing seam (compared to the Junior H-F’s 1″ thick standing seam).
EkoBuilt’s model home (design shown above) is fairly typical for our approach to roofing: the back wall is 8 feet tall, and the front wall rises to 14 feet. In this case, the Junior H-F roofing works well for the slope. A recent client wanted the front wall to be no higher than 12 feet, so we used the thicker Heritage product in that case.
Heavy snow loads on a low slope roof
As we ship our passive house kits across North America, we have to know that our approach to roofing works, especially for snow loads.
Essentially, our homes can handle any snow load. At the design stage (whether we work with a pre-existing EkoBuilt plan or create a custom design), we get into the snow loads for your area.
When it’s required, we’ll make changes to the internal load bearing walls to support historical snow loads for your local area. We also source the roof system materials from local roofing manufacturers, and these are the experts who know what’s needed where you live.
A home built with our Hummingbird plan in Lake Placid, New York had a snow load of 75 pounds per square foot, quite a bit higher than our local area (Ottawa, Canada, 47 pounds/sq ft). In this case, we made an adjustment to the internal wall separating the bedrooms from the main living space, shifting to 2 x 6s from 2 x 4s. That’s all that was needed.
Extreme snow loads
Another client in Maine is in an area where snow loads have hit 90 pounds per square foot. In this instance, the local roof truss manufacturer simply engineered the roof with additional trusses. Typically placed every 24 inches, in this project, they were placed every 16 inches.
Our approach to sourcing key materials, like roof trusses, locally, works so well for this reason. It’s also a greener approach, avoiding needless shipping.
Ready to discuss your dream of a passive home? If you plan to build in North America, just reach out to us, and we’ll help make it happen!