New Habitat Approaches: Build Roofs First

On one Denver, Colorado back lot 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.

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.” 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. A video interview with Mr. Nez can be seen here.

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.

“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.

Source: George Nez