"'The traditional houses have many environmental advantages,' said Abdulla Zaid Ayssa, the director of the government office that oversees all building and renovation in the Old City.
"The traditional plaster, joss, does not erode stones over time the way cement does, Mr. Ayssa said, and is more durable. Qadad, a stone-based insulation material used in roofs and bathrooms, is much stronger than modern equivalents. The old stones and insulation techniques are calibrated to the sharp temperature shifts of night and day in Sana’s desert climate, so that the sun’s warmth fully penetrates a house’s walls only at day’s end, and is then retained through the night and no longer, Mr. Ayssa said. They are also much more soundproof and private than concrete.
"'They experimented for hundreds of years to find these techniques,' Mr. Ayssa said. 'By comparison, nowadays we are building houses with a very stupid concept.”'"