Conservation compendium Part 10: Corrosion of steel frames behind masonry elevations-assessment and treatment

摘要

1. The work should be considered as maintenance. 2. Water needs to be kept out of the fabric, particularly from around the areas where the steels are. This may involve adding lead flashings and shedding the rain off the front of the cornices. 3. Thermal movement will continue to occur and, therefore, the mortar should be designed to accommodate this movement. The replacement mortars should be based on a sand/lime mix wherever possible (including the bedding dabs on the new stone). 4. The treatment of the steelwork should be as thorough as possible and of reasonable quality in order to prevent repeat work. 5. As little water as possible should be used when cleaning the masonry and cleaning trials should be undertaken before the main contract. 6. Consideration must be given to the amount of noise being created and the implications for any occupants of the building. It may be beneficial to use high-pressure water to cut the blocks out and for the original blocks/bricks to be reused. 7. A good record of the work should be made by taking photographs before opening up, before cleaning the steel, after cleaning the steel and when the masonry is completed. 8. Matching glazed brick colours will be time-consuming and it may be impossible to match all of the existing colours, as they will vary across the elevation. The same will apply to terracotta blocks, as modern kilns produce too uniform a colour across the block.