MARK PHILLIPSON and ALASTAIR STUPART Building Research Establishment, Scottish Laboratory

An analysis of temperature data recorded from various parts of walling exposed to natural weathering over two winters is described and related to both climatic conditions at the sites and the deterioration of the test masonry.
1. The number of temperature transitions through (PC differs markedly depending on the site and part of the wall being considered. A high number of transitions at the coping surfaces indicates the harshness of conditions at this position, confirmed by large amounts of observed frost damage.
2. Surface temperatures of vertical waiting are shown to be closely related to air temperatures, whereas coping temperatures are more closely related to ground temperatures.
3. Analysis of recorded temperatures and the deterioration of the test walls suggest that masonry temperatures cycling through -2″C is significant in determining whether frost damage occurs. This is suggested as being important for evaluating the frost performance of clay brickwork.