While some buildings with leaks have a single cladding type, many have multiple claddings or are partly constructed of concrete or concrete masonry where no defects have been identified. Partial recladding may be an option where the failure is not widespread and can be isolated to a single face, cladding type or portion of a clearly defined wall area.
To assess the opportunity for partial recladding, the designer needs to assess the way the building has been clad, the number of claddings, the detail at cladding junctions and penetrations and the relationship of upper floors to those below in buildings of more than one storey. They must also assess whether the defects identified are likely to exist in other locations if the cladding is the same type and details are replicated around the building, as well as the on-going value and stigma of leaks in the building.
However, before committing to a partial recladding, consider:
- whether it will address the weathertightness issue identified
- whether the problem is due to a single cause and not widespread
- the financial viability.
If a decision is made to partially reclad, the designer should document the reasoning – in particular, why it is a viable option given that it leaves open the possibility that not all weathertightness problems will be identified, that the damage may be more extensive than first estimated and that problems might develop in the future. For example, the problem may be a single leaking window, but if all windows have been detailed and installed in the same way, the risk of them leaking in the future must be factored in to the repair option chosen.
Advantages of partial recladding can include:
- avoiding the need to remove a sound cladding
- lower costs than a full reclad
- less disruption to occupants - it is more likely that the building may able to be lived in while work is carried out
- damage behind the removed cladding is observable.
With partial cladding:
- on removing the cladding, a full reclad may become necessary because of the extent of the damage
- the existing framing may not be treated to a level that provides sufficient resistance to future moisture entry should it occur – H1.2 treated timber is now required where direct-fixed cladding is proposed, and this may lead to designer to recommend a full reclad where timber is untreated or treated to H1.1
- it may be difficult to integrate the new cladding with existing (Can the junction be flashed? Is there a defined junction such as an internal corner to finish the new cladding to?)
- it may be difficult to insert new flashings
- not all damage may be discovered – some fungal infection of timber or leaks may remain
- there is limited opportunity to upgrade
- the repair may not satisfy the BCA that Code compliance has been achieved, especially where a direct-fixed monolithic cladding is retained
- the repair is likely to have a significant impact on the future value of the building, particularly in situations where the cladding is of a single cladding type.
For buildings with a single cladding, a failure may be isolated to one face of the building or a particularly clearly defined specific area of the wall.
Reasons for this, which should be identified in the building condition and remediation report, may include:
- the affected wall has a different cladding and/or is more exposed to the prevailing wind and rain direction
- the remaining walls are sheltered by trees, buildings or banks
- the colour of the affected wall, for example, a darker colour means more thermal movement
- the affected wall has no eaves while other areas of wall have eaves or verandas or canopies
- the affected area is difficult to maintain or has been poorly maintained compared to other areas
- different tradespeople were used on the affected area
- the affected area has features not found on other elevations, such as scuppers, balconies, curve-topped windows, complex roof to wall junctions and so on.
Where there is more than one cladding, the failure may be able to be clearly related to the one cladding type, with all remaining cladding on that face of the building showing no identified water entry or dampness.
In buildings of more than one floor, it is common for the upper floors to have a different cladding from the lower – for example, brick veneer to the lower floor and weatherboards or monolithic cladding to the upper floor. With these buildings, the issue to be determined is whether a failure in the upper floor cladding has resulted in damage to the floor framing and lower floor wall framing as well.
Adding further to the complication are buildings where the upper floor is inset from the lower, usually in response to boundary set-back requirements.
In these buildings, a leak in the upper floor is more likely to affect the mid-floor framing and the ceiling linings. The ground floor cladding and wall framing may be sound because they are not directly below the upper floor walls, leading to replacement of the upper cladding only.
However, it is likely that there will be some damage to mid-floor joists, flooring and ceiling linings.
If the ground floor is sound, a partial repair of the upper floor cladding is an option where the problem is isolated to one face. Where walls of both floors are damaged and/or there is damage on all upper floor walls, it is likely that upper floor joists will also be affected and the failure is widespread, necessitating full cladding replacement on both floors.
During a partial reclad, it may also be necessary to consider:
- specifying the installation of temporary spouting and downpipes to reduce the potential for wetting the walls being rebuilt
- allowing time for wet (but not decayed) framing to dry
- specifying the top venting of cavities to increase the drying potential (provided the opening is designed to prevent water entry)
- future value/saleability
- future liability for works completed.
Updated: 9 September 2014