Common reasons cracks reopen
- Normal settlement and seasonal thermal movement that repeatedly opens and closes a junction.
- Reactive clay soils, common through Melbourne's western suburbs, changing volume between wet and dry periods.
- Movement along plasterboard sheet joints where tape is missing, damaged or poorly embedded.
- Junctions between materials that move differently, such as masonry meeting timber or cornice meeting a ceiling.
- A rigid or unsuitable filler used where limited flexibility or reinforcement was needed.
- Water entry, condensation or persistent damp weakening the plaster or repair.
Warning signs to investigate before repainting
- A crack is widening, lengthening or returning quickly after repair.
- Stepped or diagonal cracking appears through masonry or on both sides of a wall.
- Cracking occurs with sticking doors, uneven floors or visible separation at openings.
- Staining, softness, bubbling or mould suggests an unresolved moisture source.
A careful cosmetic repair process
Assess and monitor
Check the crack's width, direction, location and history. Refer uncertain or concerning movement for appropriate building advice.
Resolve moisture
Repair leaks or ventilation problems and allow the substrate to dry. Filling over damp material will not last.
Prepare the opening
Remove loose material and open a stable cosmetic crack where necessary so the repair compound can bond to sound edges.
Reinforce where suitable
Use the appropriate filler and, for suitable plasterboard joints or repairs, correctly bed mesh or paper tape rather than bridging the line with paint.
Sand and prime
Sand the cured repair flush, remove dust and prime the repaired area to control porosity before finish coats.
When painting is not the answer
A painter can prepare and finish stable cosmetic cracking. Painting cannot correct footing movement, framing movement, water entry or structural failure, and Baku Painting does not diagnose structural problems.
If cracking is wide, progressive, stepped or accompanied by other movement, arrange an assessment by a suitably qualified builder or structural engineer before repainting. That avoids concealing evidence and repeating a cosmetic repair that cannot hold.