ABSTRACT
Modern construction methods based on curtain walling systems rely on obtaining an effective seal between the joints. The occurrence of wet-applied sealed joint failure can, in part, be attributed to the movements which occur in the external envelope. Such movements can be both large and rapid if large lightweight cladding panels are involved which are also heavily insulated.
The rates and amplitudes of actual joint movements were measured on the predominantly south-facing aspects of two modern office blocks in London. One building was concrete-clad and the other was aluminium-clad. Detailed weather records for the monitoring period were collected so that joint movements could be related to panel surface temperatures, air temperatures, solar gain and precipitation.
Experimental cyclic movement rigs were developed which could simulate the measured rates and amplitudes of real joint movements, imposed on International Standards Organisation (ISO) tensile adhesion joints. The design of these rigs was refined to enable ease of joint fabrication ‘in-situ’ and greater control over the test parameters. Preliminary experimental results confirmed the adverse effects, particularly on one-part sealants, of joint movement during cure.
