Designers should balance the risks and benefits of each remediation option before making a decision about the best approach.
Each option has advantages and disadvantages. While a total reclad is most likely and often the preferred option to eliminate the risk of further damage to the building, in some circumstances, it may also be more extensive and expensive than actually needed.
Lower-cost options will generally carry greater risk in terms of potential for defects to remain hidden, further damage to occur, BCAs to withhold Code compliance certificates and the owner and designer to be held liable for defects in the future.
In determining the appropriate response, consider:
- the extent and nature of leaks
- the type of timber and level of treatment
- the cladding materials, quality of installation and current condition
- the estimated underlying damage to framing and materials
- the complexity of the building form and the presence of risk features
- site exposure.
As a general rule, if the building has untreated timber framing with a leaking direct-fixed monolithic cladding, the cladding will need to be removed in order to assess framing damage, facilitate replacement of decayed timber and treat any remaining sound timber and surface moulds. It is also unlikely that widespread leaks (for example, leaking of all window installations and apron flashings) could be successfully remediated without removing cladding entirely.
In some cases, it may be more cost-effective to remove and replace the affected building elements rather than retain and repair them, as repair can be more expensive than demolition and replacement.
Other factors to consider include:
- legal requirements – including Building Code requirements and the legal requirement for designers and other professionals to exercise reasonable skill and care in the advice and service they provide
- what the owner wants
- what the owner can afford
- what is reasonable in terms of costs and benefits.
The scope of work should not compromise on what the building must have done to it to make it weathertight. If the owner cannot currently afford the repair, a temporary repair is a valid option to place the building in a holding pattern until full repair can be done.
Updated: 9 September 2014