Visiting the site first has the advantage that the designer has no preconceived notions of the problem and its extent, but visiting the site after being fully informed of the issues may allow a better assessment to be made.
The designer should visit the site and compare any findings from that visit with the building condition and remediation report.
A thorough site inspection is necessary for the designer to:
- understand what they are dealing with
- identify what might influence the building’s current and future weathertightness and durability.
The inspection allows a designer to:
- highlight the building’s risk features
- highlight specific concerns that may have been identified with the building
- assess the quality of workmanship, original construction detailing and the level of maintenance that has been carried out
- identify any visible evidence of weathertightness failure – a building may not exhibit any internal visible signs of leaking or obvious signs of damage from leaking
- identify problems (other than weathertightness) that may need consideration by the owner such as poor internal ventilation (particularly in bathrooms and laundries and from unvented driers or unflued gas heaters), damp subfloors, failure of bathroom waterproofing or overflows from spouting and bathroom fittings
- check the wind zone and weather exposure of the building – are there one or more faces that have a higher level of exposure to the weather?
- look for evidence of previous repairs or patching that may have sealed in existing dampness
- identify changes that may have been made during or after construction – not all changes made will be identifiable or will have been approved (for example, a change to the level of timber treatment) but changes from the cladding specified and changes to building layouts should be easily identifiable
- identify changes that have been made since the building was completed, such as building up the ground or paving against the cladding
- identify restrictions that might apply to access, material storage, and scaffolding
- observe changes to and the condition of adjacent buildings if of a similar design.
Observations should be cross-checked with the information that is contained in building reports and other documentation to inform the development of repair options.
Building investigations can sometimes reveal severe decay that is threatening to the structure of critical building elements. This requires immediate engineering inspection and action, such as temporary repairs, propping, closing off certain parts of the building and consulting with the BCA.
In addition to the high-risk design features (discussed in Risk evaluation), other factors that influence the amount of damage can include:
- framing treatment levels
- the location of the leaks
- how long the building has been leaking
- how much water has been getting in
- weather conditions at the time the building was surveyed
- the time period between assessment and beginning repair work.
The amount of water that is getting in will be influenced by:
- the quality of the cladding detailing and installation
- the maintenance carried out
- material failure – cladding, sealant, coating
- weather exposure and prevailing wind direction
- cladding type
- absence of flashings
- building complexity
- repairs that may have been carried out – if these have not been well done, they can exacerbate problems by trapping moisture within the building or not addressing the actual cause of the water ingress
- extent and seriousness of defects.
The difficulty with framing that has had some level of treatment is determining:
- what treatment was actually used (which may not be what was originally specified)
- where the timber was sourced from – even within one building, the level of treatment may vary between different suppliers
- the amount of treatment chemical used during manufacture – testing has shown that some untreated framing contains some traces of boron treatment
- the level of retention of the treatment chemicals in the timber over time.
The only reliable evidence of timber treatment comes from removing timber samples and having these laboratory tested for treatment types and levels.
Updated: 9 September 2014