Rising Damp in Inner West
Damp, salty, crumbling brickwork at the base of a wall — rising damp is an old-building problem that needs an old-building fix.
Why we see this constantly in the Inner West
Inner West terraces and cottages built before about 1920 either had no damp-proof course or had a slate DPC that's failed. Rising damp shows as a tidemark up the inside of skirtings, salt bloom at the wall base, and paint blowing off render. The wrong fix — cement render on the outside, paint on the inside — traps moisture and makes it worse. We do chemical DPC injection plus removal of any non-breathable coatings, then lime-based render that lets the wall dry properly.
Newtown, Balmain, Marrickville, Leichhardt, Glebe and Surry Hills are dominated by Victorian and Edwardian terraces, workers' cottages, and converted warehouses. The brickwork is mostly Sydney red brick on lime mortar, often with original tuckpointing under decades of paint or render. Reactive clay soils under many streets cause footing movement, and the age of the housing stock means almost every job involves heritage-appropriate materials.
What is rising damp?
Rising damp is groundwater moving up through masonry by capillary action, carrying salts that crystallise and break down bricks and mortar. It is common in pre-1930 Sydney buildings with failed or missing damp-proof courses. The correct fix is injecting a new chemical damp-proof course, removing impermeable modern render and paint, and re-rendering with breathable lime-based materials. Cement render and waterproof paint make rising damp worse, not better.
Signs to watch for on your property
- Tidemark or staining about 1m up from floor level
- Salt efflorescence (white fluffy crystals) on the wall surface
- Paint or render bubbling, flaking or falling off in the affected zone
- Mortar crumbling when you scratch it with a key
- Musty smell in rooms with affected walls
- Damp patches at the base of internal walls
- Timber skirting boards rotting or warping
Suburbs we cover in Inner West
We work right across Inner West. Click a suburb for site-specific notes on housing stock and common issues.
How we fix it properly
1. Confirm it is actually rising damp
Rising damp is often misdiagnosed. Penetrating damp, condensation, leaking pipes and bridged damp courses all look similar. We test moisture levels and salt profiles to confirm before spending money on the wrong treatment.
2. Remove failed modern materials
Cement render, waterproof paint, vinyl wallpaper — anything impermeable in the damp zone comes off. These are what cause the damp to spread and build up salts.
3. Install a new damp-proof course
For older buildings we typically inject a chemical DPC — silane or siloxane cream injected into the mortar bed at ground level. Cures and forms a water-repellent barrier. For heritage work with lime mortar, we match the DPC system to the wall.
4. Re-render with breathable lime
Lime-based render and plaster let the wall dry out instead of trapping moisture. This is the opposite of modern cement render. It takes longer to cure but the wall breathes the way it was designed to.
5. Address the ground and drainage
Lower garden beds and paving so they are below the damp course. Re-direct stormwater away from the wall. Without this the new damp course will eventually be bridged again.
Got rising damp in Inner West?
Call Minas for a real assessment. We give straight answers and proper quotes — no high-pressure sales.
0414 922 276