The present work has been performed within the framework of a wider research program investigating the rewetting of high-temperature walls using droplet impingement and falling film. Specifically, it deals with experimental tests focusing on the cooling of vertical, nonmetallic (chalk) walls using water sprays characterized by a uniform (I-D) distribution of drop diameter In addition, the heat flux at the wall is directly calculated from the thermocouple reading. Tests have been carried out using two different wall configurations. The first is related to the use of chalk as wall material; the second test examines a section in which chalk is coated with a thin aluminum layer to prevent direct water/chalk contact; this latter is responsible for many problems (surface deterioration and surface breaks during the tests). Only one drop size has been used in the water spray cooling as from previous tests, this parameter has not been found to be very effective on the phenomenon. Finally, experimental results obtained with the chalk test section (coated and uncoated) are compared to results obtained using a stainless steel test section.