Prior to the 1950’s most high-rise buildings had facades were made of natural stones, clay brick and other such materials built proud of cavity walls. Openings were made into which fixed and operable windows were installed into.
Since the 1950’s the dominant method and preferred aesthetic for Iconic building exterior façades has been curtainwall which uses a matrix of aluminum vertical and horizontal framing as the main structural elements with vison and opaque glass. These walls were also referred to as barrier walls since they did not incorporate a cavity wall.
Barrier wall curtainwall glass buildings, those built in the 1950’s and today as graceful as they are, readily exchange energy, through both their metal frames and vision glass.
In the 1980’s many new residential high rise used conventional aluminum framed window wall often with an exposed concrete slab. This approach was known as “exposed eyebrow”. This approach was inexpensive but left a gap in the design specifically allowing a buildings structure to readily allow energy to escape. A thermal bridge was introduced, and many problems associated with this design linger.
A new approach was introduced known as slab covers, they would cover the exposed eyebrow, acting as an aesthetic and sometimes included some level of insulation. Slab covers introduced other problems specifically allowing air and water to enter by way of faulty workmanship or over time by eroding seals.
Curtainwalls and window walls, that were once barrier walls are now designed around pressure equalized and rain screen approaches and have dominated the market. They all have their strengths and shortcomings.
In 2005 a new system would allow vertical curtainwall type assembly to be notched around the slab. We saw a huge and successful effort with this design. The design had a vertical notch in the vertical mullion which would allow a window wall which appeared like a curtainwall to cover the slab. This approach worked and very many projects that would otherwise be conventional window wall, as described above, would now belong to this Canadian group.
Success of the system described above, was followed by multiple efforts to copy the approach several companies first designed systems that infringed on the patented design but soon others navigated around the patent claims. They all figured out that we can just notch the vertical another way and take advantage of the patented design gap in protection.
All these systems have a common design approach, and all present benefits and challenges.
With updated energy codes, including more stringent thermal loss and gains through framing and those related to air tightness have provoked creative solutions to building façade designs. With these solutions challenges must be overcome as well.
That is where the story of the Portal-Wall™ a patent pending approach begins.