WOLLONGONG MOULD REMOVAL SERVICES
Rising Damp Treatment in Wollongong
Get a tape measure. If the damp starts higher than about 1.2 metres off the ground, it is not rising damp, and a chemical damp course will not fix it.
Trusted Rising Damp Treatment
Paint bubbling and flaking along the bottom of the wall. A tide mark about knee height that never quite dries out. A chalky white crust you can rub off with your thumb, and it comes back a month later. Skirting boards going soft. Someone has told you it is rising damp and quoted you four thousand dollars to inject the walls.
Before you spend that, get it measured, because rising damp is one of the most over-diagnosed problems in Australian housing.
The NSW Government’s own technical guidance on the subject says it plainly: in humid climates condensation is the more significant problem, and misdiagnosis of damp problems as rising damp is common. Plenty of walls that get injected never had rising damp. They had a leaking downpipe, a bridged damp course, a cracked shower base on the other side, or condensation on a cold wall.
The team at Wollongong Mould Cleaning & Removal been doing this across the Illawarra for 15 years. What we do on this job is the diagnosis: moisture readings, the pattern, the height, the source, and a straight answer about which of the four or five possible causes you actually have. The damp-proofing itself is licensed work, so where a new damp course really is the answer we organise a licensed damp-proofer, coordinate the sequence, and stay the single point of contact through the whole job.
- Paint bubbling, blistering or peeling in a band along the bottom of a wall
- A white powdery or crystalline crust on brick, render or paint that keeps returning after you wipe it
- Skirting boards or architraves soft, swollen or lifting at the base
- Mortar crumbling out from between the bricks low on an external wall
- A musty smell near the floor in one room, worse in winter
- A damp patch that has survived being painted over more than once
The mould inspection is free, and the outcome is often that you do not need the expensive fix.
FREE INSPECTION, NO OBLIGATION
We will call you back personally to arrange a time.
Rising Damp or Something Else, Which One Have You Got?
Four things look almost identical on a wall and cost wildly different amounts to fix.
Rising damp is ground moisture drawn up through masonry by capillary action, because the damp-proof course has failed, was never there, or has been bridged. NSW Health describes it as ground moisture rising up a brick or stone wall, worsened by poor subfloor ventilation. It shows as a horizontal band with a fairly even top edge, at a consistent height along the wall, and it usually carries salt with it.
Lateral damp comes in sideways, from soil or paving sitting against the wall or from a retaining wall behind it. Looks similar, sits at a similar height, needs a completely different fix.
A leak comes from a downpipe, a garden tap, a shower or a pipe in the slab. The pattern is the giveaway: leaks make a patch with an irregular edge, often wider at the top or centred on a fitting, and they do not run evenly along the whole wall.
Condensation forms on cold internal surfaces and produces mould rather than salt. It is worst in winter, worst on southern walls, worst behind furniture. This is the most common of the four in coastal NSW and it needs no damp course at all. That one is covered on wall mould removal.
If the damp is under the house rather than in the wall, or the floorboards have started cupping, start at subfloor and mouldy floor treatment instead. If you want the moisture properly documented before a purchase or a dispute, that is the mould inspection and testing hub.
How We Diagnose and Treat Rising Damp
1. Free inspection and moisture mapping
Readings taken in a grid up the wall and along it, inside and out, plus the subfloor where there is one. The shape of the wet is what identifies the cause, so we map it rather than taking one reading and calling it.
2. Check the obvious bridges first
Soil, garden beds, mulch or paving above the damp course. Blocked or buried weep holes. A concrete path poured against the wall. A downpipe discharging at the base. These are common, they are cheap to fix, and they are the reason a lot of quoted damp courses were never needed.
3. Establish whether salt is involved
Salt on the surface changes both the diagnosis and the repair, and it is the step most quotes skip. Where it matters, samples get sent to a laboratory rather than guessed at. More on why below.
4. Written report and a scoped plan
What it is, where the water is coming from, what has to happen and in what order, and what it will cost. Including the version where the answer is a shovel and a Saturday.
5. Coordinate the licensed repair
Where a new damp-proof course is actually needed, we organise a licensed damp-proofer and stay across the job. Where the cause is drainage, plumbing or a subfloor, we organise that trade instead.
6. Deal with the salt-loaded render, then reinstate
Contaminated render comes off and goes back as a breathable sacrificial render, not a hard cement one. Then drying, mould treatment where there is any, and reinstatement. Larger reinstatement runs through building restoration.
Why the Wall Stays Wet After the Damp Course Is Fixed
This is the complaint we hear most often about work done by other people. Someone paid for injection, waited the six months they were told to wait, and the wall is still damp. They think they were ripped off. Usually they were not. They were just sold half a job.
The damage in a damp wall is not really done by water. It is done by salt.
The NSW Government’s guide to salt attack and rising damp describes the mechanism: soluble salts come out of the ground with the moisture, get carried up into the wall, and are left behind when the water evaporates at the surface, because salts cannot evaporate. They accumulate. Then they crystallise inside the pores of the brick and mortar, and as the crystals grow they break the masonry apart from the inside, which is the fretting and the crumbling mortar you can see.
Here is the part that explains the wall that will not dry. Many of those salts are hygroscopic, meaning they pull water out of the air. The guide is direct about it: where there are salts in the masonry, the amount of water drawn in and held can be enough to make the wall visibly damp even in dry weather. So once a wall is salt-loaded, it will keep reading wet and keep looking wet in humid conditions no matter how good the new damp course is, because the moisture is now coming out of the air rather than up from the ground.
That has two consequences worth knowing before you hire anyone.
A moisture meter reading on its own does not prove you have rising damp. Salts read as moisture on a handheld meter. The NSW guide is specific that the only method which distinguishes moisture due to rising damp from moisture due to hygroscopic salts is a laboratory one: drill samples, dry them, let them come to equilibrium at 75 percent relative humidity, and reweigh. If someone waves a meter at your skirting board and quotes you for injection on the spot, they have not established what they say they have established.
Fixing the damp course without dealing with the salt-loaded render leaves you with a wall that still looks broken. The render holds the salt. It has to come off and go back as a sacrificial render that lets the wall breathe and gives the remaining salts somewhere to go.
Which brings up the trap the same guide singles out. Rendering the base of a wall in hard cement render is described as a very common but poor treatment, because it does not stop the damp, it just stops the evaporation. The moisture keeps rising in the masonry behind the render until it can get out above it, and the problem starts again higher up the wall. If a previous owner has patched the bottom metre of your wall in hard grey render and the damp has appeared just above it, that is not a coincidence.
So the honest sequence: measure it, prove it, fix the source, deal with the salt, then render breathable. Anyone offering you step three on its own is selling you a wall that will still be damp next summer.
Bricks, Sandstone, Skirtings and Subfloors: Where Rising Damp Does Its Damage
Rising damp rarely stops at the paint. These are the places it shows up and what each one needs.
- Mould appearing on the wall above the damp band is a separate problem riding on the same moisture, and the surface side is covered on wall mould removal.
- If the smell is coming up through the floor and the boards are cupping, the moisture has reached the subfloor and that is subfloor and mouldy floor treatment.
- Fretting brick, crumbling mortar and blown render on the outside of the wall are salt attack, and the exterior surface work sits with exterior mould removal and house washing.
- Where growth has gone through the plasterboard rather than sitting on it, that becomes structural mould remediation.
- If you are buying an older brick or sandstone home and want the damp assessed before you sign, that is a pre-purchase mould inspection.
- If the wall is in a unit or townhouse, the wall may be common property and the cost may not be yours, which is covered on strata and body-corporate mould.
How Much Does Rising Damp Treatment Cost?
The inspection is free, and a decent number of these jobs end with us telling you to move a garden bed rather than sending an invoice.
| Severity | What it looks like | What it takes | Cost |
|---|---|---|---|
| Do it yourself | Soil, mulch or paving sitting above the damp course, weep holes buried, downpipe dumping at the base of the wall | A shovel, clearing the weep holes, an extension on the downpipe, then a season to dry | $0 to $200 |
| Minor | One wall, damp course intact but bridged, no significant salt damage to the masonry | Drainage correction, subfloor ventilation improved, render patch, monitoring | From $1,000 |
| Moderate | Failed or absent damp course on one or two walls, salt visible, render blown, skirtings gone | Injected damp course by a licensed damp-proofer, salt-loaded render removed, sacrificial render, drying, reinstatement | $2,500 to $10,000 |
| Major | Multiple walls, fretting brickwork, mortar loss, subfloor and flooring affected | Damp course throughout, masonry repair, subfloor works, extended drying, full reinstatement | $10,000+ |
| Severe | Heritage or sandstone building, structural masonry decay, long-running salt attack | Staged conservation works, laboratory salt analysis, specialist trades | $20,000+ |
These are current Illawarra market rates for scoping purposes. The licensed damp-proofing component is quoted by the damp-proofer, not by us, and your figure comes from the free inspection.
The number that moves the cost the most is how much masonry has already gone. Injecting a damp course into sound brickwork is a day’s work. Injecting it into brick that has been fretting for 15 years means rebuilding courses first, and that is when the price goes up.
Time is the other honest thing to raise. A wall that has been wet for years does not dry in a fortnight. Expect months, not weeks, before it reads dry, and expect it to look worse before it looks better as the salts come to the surface. Anyone promising you a dry wall next week is either not being straight with you or has not understood the problem.
How Our Local Illawarra Knowledge Changes the Job
Two things make damp behave differently here to almost anywhere else in the country.
The first is what the ground does. A lot of the older housing stock across Woonona, Bulli, Thirroul, Corrimal, Figtree and Balgownie is solid brick or brick veneer from the post-war decades, built on sloping blocks under the escarpment with the ground dropping away one side and banking up the other. Over sixty years those homes have collected concrete paths, pavers, retaining walls and raised garden beds added by successive owners, and every one of them raised the ground level against the wall. That is the single most common cause of what gets diagnosed as rising damp around here, and NSW Health’s own advice on the subject is to make sure the weep holes and air vents at the base of the house are uncovered. Free, and it works.
The second is the salt. Living this close to the water means airborne salt is landing on external masonry constantly, on top of whatever is coming up out of the ground. Salt is the thing that actually destroys the brick, so coastal Illawarra walls fret faster than the same wall would in Camden. It also means a salt reading in this region needs interpreting rather than assuming, because some of it arrived from the sky rather than the soil.
Practical upshot: on an Illawarra job, we look at the ground level and the drainage before we look at the damp course, because most of the time that is where the answer is.
We work the whole Illawarra: Wollongong and the northern suburbs, Port Kembla, Unanderra, Dapto, Albion Park, Shellharbour and down to Kiama.
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Free on-site inspection, moisture properly mapped, and a straight answer about whether you need a damp course or a shovel.
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Frequently Asked Questions
How do I know if it is really rising damp?
Measure the height.
NSW Government guidance puts the normal exterior height limit for rising damp in Australia at 1.0 to 1.5 metres above ground level, with the visible evaporative zone usually between 0.5 and 1.2 metres, because how high water climbs is limited by how fast it evaporates off the wall. Damp that starts above waist height, sits in the middle of a wall, or runs to the ceiling is coming from somewhere else. The other tell is the edge, rising damp makes a fairly even horizontal band, while a leak makes an irregular patch.
What is the white powdery stuff on my brickwork?
Salt.
It comes up out of the ground dissolved in the moisture and is left behind on the surface when the water evaporates, because salt cannot evaporate with it. It matters more than it looks, because those salt crystals growing inside the pores of the brick and mortar are what actually breaks masonry apart, and many of them attract water out of humid air, which keeps the wall damp on its own.
Does a chemical damp course actually work?
Injected damp courses are a legitimate and widely used repair when rising damp is what you have.
The reason they get a bad name is that they get sold to people who did not have rising damp, and that when they are installed without removing the salt-loaded render the wall stays visibly damp afterwards and everyone assumes it failed. Prove the diagnosis first and deal with the render second, and it does the job.
Can I fix rising damp myself?
Sometimes, and it is worth checking before you pay anyone.
If soil, mulch, pavers or a concrete path have been built up above the damp course, or the weep holes at the base of the wall are buried, or a downpipe is discharging next to the footing, then clearing that is the fix and it costs you an afternoon. NSW Health’s advice is to keep weep holes and air vents uncovered. Give it a season and see what the wall does before spending thousands.
Why has painting over it never worked?
Because the moisture is behind the paint, and paint is a barrier.
Sealing the surface stops the wall evaporating where it currently evaporates, so the moisture simply travels further up the masonry and comes out above the paint line. The NSW guide makes the same point about hard cement render at the base of walls: it is a common treatment and a poor one, because it moves the problem up rather than stopping it.
Is rising damp dangerous to my health?
The damp itself is a building problem rather than a health one, but it produces conditions mould likes, and that is the health question.
NSW Health states that most people will not experience health problems from contact with mould, while people with asthma, allergies, weakened immune systems or chronic lung disease can be more sensitive. Remove the mould and fix the moisture either way, and see a doctor if anyone is unwell.
Do you do the damp-proofing yourselves?
We do the diagnosis, the moisture mapping, the report, the salt-affected render, the mould side and the reinstatement. Installing a damp-proof course is licensed work, so we organise a licensed damp-proofer for that part and coordinate the job around it, with one point of contact for you.