Is it acceptable to just apply new sealant over the old joint?
Generally not as a permanent repair. New sealant applied over failed, contaminated or debonded sealant often fails at the interface because it never bonds to the substrate. Durable sealant repair normally means removing the old sealant, cleaning and priming the substrate as the sealant manufacturer specifies, and installing new sealant with the correct joint backing. Adhesion can then be checked by testing on installed joints.
From the RRD Field Guide, checked against the sources cited in Façade Defect Rectification in Singapore: What Happens After the PFI Report. General information, not advice for your project.
The fuller picture
After BCA accepts a PFI report, the owner must carry out the Competent Person's recommended repairs within the period BCA specifies. Make unsafe areas safe first, then repair by defect type: sealant, cladding, glazing, spalling concrete, corroded fixings, hollow tiles or windows. Structural repairs need plan approval, a permit and PE supervision; completion is certified with photos.
More questions on this topic
- How long do I have to complete PFI repairs?
- Do I have to repair the whole façade or only the 10% that was inspected?
- Can the contractor certify that the repairs are complete?
- When do façade repairs need a Professional Engineer?
- What temporary safety measures are required while waiting for repairs?
- We are replacing aluminium composite cladding panels. Are there fire rules?
- Who can replace windows found defective during the PFI?