The residential roofing market may soon change due to the ingenuity of architect Jose Henriquez and engineer Francisco Bermudez, who have developed a method of forming and building sloping roofs of reinforced concrete that uses commonly available construction materials and methods.
Forming for the roof begins with post or scaffold-type shoring, erected to support wood joists and stringers. Workers place the form sheathing—4x8-foot sheets of polyisocyanurate insulation board, 2 7/8 inches thick—directly on the joists, which are typically spaced 16 inches on center. A network of metal or plastic channels placed along the edges of the insulation board projects above it to support the roof. Embedded 3/4 inch into the roof slab after concreting, these channels retain the insulation and serve as attachment points for interior ceiling finishes.
Workers can assemble the formwork on the ground in large sections then use a crane to lift the sections into place. A stiff concrete mix is pumped into place, with workers advancing up the slope to vibrate and finish the concrete to the desired thickness. Roofs can be finished with an elastomeric coating, conventional roofing or clay tiles.