Authors: Tripti Singh Ian Simpson Dave Page
Publish Date: 2016/05/27
Volume: 74, Issue: 5, Pages: 703-710
Abstract
The quest to understand remedial treatment for timber framing began following the ‘leaky building crisis’ in New Zealand which came to prominence in late 1990s Several in situ remedial treatment products are used in New Zealand However effectiveness of these treatments is still unclear particularly in situations where not all faces of the timber can be accessed This research was conducted to establish whether a ‘double coat brushon’ or ‘double coat brushon plus injection treatment between studs’ system would give the most surface coverage and retention of a commonly used remedial treatment chemical boron Results showed that in the ‘double coat brushon’ process the concealed surfaces were left largely untreated resulting in variable preservative retention between components and relatively low overall preservative retention in the multiple stud units However the ‘brushon plus injection treatment’ application gave much better preservative spread onto concealed surfaces of both vertical and horizontal members Most samples tested achieved average crosssection boron retention levels of 04 BAE m/m NZS 3640 H12 treatment specification although the treatment was concentrated in the outer 30 of the timber hence not achieving the required full sapwood penetration Because of the variability associated with the boron injection process it is recommended that this remediation method should only be used where there is a high degree of confidence that there is no decay present between studs or lintel members All attempts should be made to remove any decaying timber while repairing leaky buildings
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