George Nez builds roofs first & habitats that help mend poverty

On one Denver, Colorado backyard, a visitor will encounter an unorthodox-looking roof that just might help meet the housing needs of displaced people worldwide. The roof, shaped like a hyperbolic paraboloid, was constructed on the ground and then lifted in place by African student builders who wanted to build similar structures in locales like Rwanda and Sudan.

The substructure is simple and inexpensive for a Nez hyperbolic paraboloid roof

Remarkably strong and weather resistant, this new age shelter contains few structural elements, can be constructed without electrical power, and costs very little money.

George Nez is the developer of this roof system, simply calling it a “hypar roof.” He explains it in this engaging, short video: George Nez_H264 3. Those familiar with his work – especially those builders in Rwanda and Sudan – fondly refer to this structure as the “Nez roof.” The roof is built using latex-modified concrete that is painted over a mesh backing.

Nez, now in his mid-eighties, once served as planning director for the City of Denver before going to work for the United Nations & USAID to help with large-scale resettlements in Africa, Eastern Europe, and South America caused from emergencies like floods or earthquakes. It was there that he implemented the idea of building roofs-first, a practice that has became his life’s work.

A lightweight concrete slurry is poured over a roof in Romania Photo: Nez

“The principle of roofs-first is to be able to rapidly, and at the lowest cost, provide shelter so the families can move in and eventually fill in their wall. They don’t have time for a slow process of building up from foundations or traditional walls and wait until they can afford a roof? No. The roof-first process builds the roofs for them.”

The roof is built with latex modified concrete that is painted over a mesh backing. “Latex is the basic element in paint and provides a kind of resilience in concrete, which is incredible.” says Nez, adding that testing on the roofs have been tested by the National Park Service and by the Knott Laboratory in Denver and show from double the normal roof requirement up to four times with resilience to hot and cold.

Nez holds a sample piece of the roof, approximately one centimeter in thickness. “This is all that’s needed, the thickness; that thickness is sufficient to park a truck on it.” It has a reinforcement core of fiberglass screen. That’s what was put across the open frame first then the cement was simply poured on there as thin slurry of latex modified concrete, sand, cement, and latex and water.

Nez is a graduate of M.I.T. as a master in city planning and holds a Ph.D. in Urban Services Administration from Columbia Pacific University. He also served as a professor of planning at Kansas State University.

The Nez roof at TSC Global in Denver Photo: TSC

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 now 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.

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.

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.

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.