Evidence of new buildings featuring an innovative and cost-effective roof can now be seen in a growing number of African nations, including Kenya, Rwanda, Tanzania, Uganda, and Sudan, as part of a Roofs for the World initiative.
This roof is called a Thin Shell Composite Hyperbolic Paraboloid, or TSC Hypar, thus the name, TSC Global, which proclaims the building methodology using this roof has the potential for revolutionizing roofing and construction in the most impoverished and remote parts of the globe. TSC Global executive director, Brad Wells, says that compared to the corrugated steel roof structures seen everywhere in the developing world, TSC roof construction requires a minimum in cut lumber, demands no power machinery for construction, and leaves almost no carbon footprint. In addition, buildings featuring these roofs are significantly quieter in rain and windstorms, and can be earthquake resistant.
Denver-based TSC Global was created to build, promote and fully develop this construction method, with the belief that there is real potential to dramatically enhance the overall quality and affordability of structures used by millions if not billions of people worldwide. It is now focusing on a potential rebuilding program for Haiti.
A TSC roof is constructed as follows: an acrylic cement composite is applied to an arched hyperbolic paraboloid shaped cloth that has been stretched across a four-sided pyramid framework using wood or bamboo. When the acrylic and cement composite cures, the product is a far superior roofing alternative to corrugated metal and other roofs, contends Wells.
Even with a final thickness of approximately one centimeter, a TSC Hypar roof is strong enough to hold heavy weights. Hypar structures have been built for decades but the most closely observed demo structure was built in 1996 by habitat pioneer, George Nez, who has worked on United Nations and USAID emergency relief projects. The TSC website reports Mr. Nez’s structure has endured Colorado winds, freezes and thaws of as much as three feet of. In warmer climates, these roofs should last many decades.
Importantly, a venting and circulation system has been added to the hypar roof in hot climates, allowing air and cooking exhaust to escape. The top vent and cap is an important and simple modification, says Mr. Nez. Adding a ceiling and sealing off the attic space will also enhance cooling.
A TSC roof, reinforced with embedded chicken wire mesh demonstrates resilience to failure or collapse, says the TSC website, adding that the lightweight roof can decrease chances of injury or worse in earthquake scenarios, even in the most severe earthquake. Recent work in overall building design by Colorado School of Mines structural engineering professor, Panos Kiousis, suggests that simple wall-embedded cross-braced panels secured to a ring beam, with adequate fastening of roofs to posts, should create an earthquake resistant building, still at low costs.
TSC structures can be constructed easily in the most remote settings with no transport of large building materials or equipment. Wells says his target populations include refugee and post-disaster projects, urban “shantytown” replacement, and general commercial and residential building construction. He adds that a further goal for his organization is to offer training and micro-finance networks.
