Paint hides water damage for a few weeks, then the problem comes back. Before any commercial repaint, find and fix the moisture source, treat mould and efflorescence properly and let the surfaces dry. Here’s what that looks like on a Brisbane building.
Signs to look for
Most moisture problems announce themselves if you know what you’re seeing:
- Brown or yellow stains on ceilings and wall tops
- Paint that’s bubbling, blistering or peeling, especially low on walls
- Chalky white deposits on masonry, called efflorescence
- Black or green spotting that wipes back but returns, which is usually mould
- Soft, swollen or crumbling plasterboard and render
- A musty smell in a closed room
Find the source first
Paint never fixes water. It just covers what it has done. Before the painters start, the cause has to be found and repaired. Common culprits in Brisbane are roof leaks, blocked or damaged gutters, failed flashing, leaking pipes, poor drainage at ground level and sealants around windows and joints that have perished.
Depending on the cause, a roofer, plumber or waterproofing specialist may need to come first. Gutters and fascias are a frequent trouble spot, and our gutters and fascia painting service covers the repair and repaint side once the water is under control.
Efflorescence: what it is and how it’s treated
Efflorescence is what’s left behind when water moves through masonry and carries salts to the surface. It looks like a white, powdery crust. It isn’t the problem itself. It’s a sign that moisture is getting in.
Treatment starts with fixing the moisture path. The deposits are then dry-brushed off and the surface is washed and allowed to dry fully. Painting over them, or over damp masonry, is the fastest way to get paint that blisters and flakes. Our post on why paint flakes and wrinkles explains what failure looks like when the substrate is wrong.
Mould
Brisbane’s humidity gives mould plenty of help. Surface mould is treated with a suitable cleaning product, and the surface is dried before recoating. Then the underlying cause has to be tackled, whether that’s poor ventilation, a leak or a shaded wall that never dries. If you skip that step, the mould is back within a season.
Where the growth is heavy or the affected area is large, get the building assessed properly before painting.
Repairing damaged surfaces
Soft or swollen plasterboard should be replaced, not painted. Damaged render is patched and cured. Once a surface is sound and dry, a stain-blocking primer stops old marks bleeding through the topcoat. Skipping the primer is a common reason ceiling stains reappear through fresh paint.
For rendered exteriors, see our render painting page, and for washing and prep, our power washing service.
Older buildings: stop and check
If a building went up before 2004, it may contain asbestos, and older paint may contain lead. Don’t sand, scrape or disturb suspect materials until they’ve been tested. If you’re not sure, get advice from a qualified asbestos assessor first. It’s a small cost against a big risk.
What a proper scope looks like
- The source of moisture is identified and repaired first
- Affected areas are cleaned, treated and left to dry
- Damaged material is replaced or patched, not painted over
- A stain-blocking or suitable sealer primer is specified
- Topcoats suit the environment
Fix it once
Repainting over a wet wall means paying for the same job twice. Our water damage repair page explains how we approach it, our article on making exterior commercial painting last covers coatings, and our guide to re-leasing and make-good painting shows why an empty tenancy is the best time to check. When you’re ready, request a quote or call 1300 733 447.
McAuliffe Painting. Eagle Farm, Brisbane QLD 4009. QBCC Lic 15183972.
