Salt damp questions, answered

Yes, and in South Australia salt damp is the name people actually use. Groundwater climbs the wall and carries dissolved ground salts with it. The water evaporates out of the face and the salt stays behind. In Adelaide the salt does more damage than the water does, which is why the local name is the more accurate one.

Because that is where the water travels. Bluestone is dense and the lime mortar between it is not, so moisture moves through the joints and the salt goes to work there first. A wall can look completely sound while the mortar behind has gone to sand. That is the single most common finding on an Adelaide assessment.

No, and this is the repair that causes the most damage in this city. Cement is harder and less permeable than the stone. Sealed out of the joint, the moisture and salt move into the face of the bluestone instead, and the stone starts to fret. The damage moves from something replaceable to something that is not.

Two hours on site at most, and a written finding you keep. Readings are taken up the wall rather than at one point, a sample is drilled from the mortar bed behind the plaster and tested for real moisture content, and salts are checked. Ground levels, paving and drainage outside are part of it. Treatment is a separate quote.

A free inspection is paid for by the work it finds. Ours is paid for by you, which means the finding can be that you do not need treatment at all. On a fair number of Adelaide jobs the answer is a garden bed and a downpipe rather than a damp course.

Many Adelaide houses do have a damp course. It just no longer works, because something has been built up past it — a raised garden bed, a new path, a slab, or render carried down to the ground. Water steps straight over the barrier. The damp course is fine. It is simply no longer the highest thing on the wall.

It reliably makes things worse on solid masonry. The coating does not keep water out of the wall, it keeps water in. The damp then rises higher looking for somewhere to evaporate, and the salt accumulates behind the paint until it lifts. Removing a sealed finish is often the first job on the quote.

Months. Injecting a barrier stops the climb quickly, but water already in the wall leaves slowly and the salt does not leave at all without the render coming off and being replaced with something that breathes. That replastering is frequently the larger half of the cost.

Usually not. Policies commonly exclude gradual deterioration and salt damp is gradual by nature. A sudden burst pipe is different. Read your policy or ask your insurer — we cannot tell you what your cover includes.

The specialist, not us. We are a referral service. The work is done by an independent damp contractor licensed by Consumer and Business Services who holds their own insurance. We arrange the assessment and step back.

Only if the cause was never found. A barrier installed into a wall whose real problem was a raised garden bed will fail, because nothing about the water changed. This is the entire argument for diagnosing before quoting.

Often it is worth diagnosing first, even if you do not treat. Salt damp is one of the things an Adelaide building inspector looks for, and an unexplained finding costs more at negotiation than a written diagnosis does. Knowing which of the causes you have puts you in a much better position.

Rising damp is groundwater soaking up into a wall from the soil underneath it. Stone, brick and mortar are full of tiny holes. Water climbs those holes the same way it climbs up a paper towel. It stops about a metre up, where it dries off the wall as fast as it arrives. That is why the mark is a level line and not a patch.

It is the same thing with a local name and a worse ending. The water rises the same way. What is different in Adelaide is what happens next. The summer drives the water back out of the wall, and the salt it was carrying stays behind. Over enough wet and dry cycles the salt crystals do the damage, not the water.

Salt damp only happens on ground-floor walls, and it makes a level line about 600mm to 1.2m up. A leak makes a patch, usually higher, and usually worst after rain. Condensation shows up on cold surfaces and in corners, and it is worst in winter. A moisture meter and a look outside settle it in about an hour. Guessing is what costs people money.

A damp course is a waterproof layer built into a wall, just above the ground. It stops water climbing any higher. Older Adelaide houses were built with slate or bituminous felt. Many of the oldest have none at all. A damp course can also fail with age, or be bridged, which means water found a way around it.

Yes. In a newer house the usual cause is that the ground outside has ended up higher than the damp course. A concrete path, a raised garden bed, a slab, a re-levelled yard — any of those lets water walk straight around the barrier. This is usually the cheapest kind to fix, because the fix is outside the house.

Yes, and this is the most common misread in Adelaide. Bluestone is dense and does not take up much water itself. The water travels up the soft lime mortar between the stones instead. So the stone can look sound while the mortar has gone to sand. Poke a joint with a key. If it crumbles out, that is your answer.

No. This is the single most expensive mistake made on Adelaide stone. Hard cement will not let the wall dry through the joint. The water and the salt then leave through the face of the stone instead, and the stone is what fails. Lime mortar is soft on purpose. It is meant to be the part that wears.

Damp walls grow mould. SA Health says mould indoors can trigger a blocked nose, sneezing, coughing and wheezing. It is worse for people with asthma, allergies, or a weakened immune system. Cleaning mould off the surface does not fix it while the wall is still wet.

No. A dehumidifier dries the air in the room. Salt damp keeps feeding water into the wall from the ground. The machine can make a room more comfortable while you sort the real cause out. It will not stop the water coming up.

Painting or rendering over damp is the most common mistake we see. A sealed coating traps the water in the wall instead of letting it dry outwards. The coating then lifts off in sheets, often worse than before, and the salt comes with it. Fix the water first, let the wall dry, then finish it.

Not usually, and this is why people think a damp course has failed when it has not. A new course stops more water arriving. It does nothing about the salt already in the wall. Salt pulls moisture out of the air by itself, so the wall keeps reading damp and keeps marking the new plaster. The salty render has to come off as well.

Injecting a new damp course runs about $180 to $260 a metre. Repointing in lime mortar is about $120 to $220 a square metre. Salt-retardant render and replaster is about $90 to $180 a square metre. Sometimes the answer is only drainage and ground levels, at about $900 to $3,500, and that is often the whole fix. Every fixed price quote follows an on-site assessment.

The physical work is usually a few days. The drying is the long part. A wall dries at roughly one month for every ten millimetres of thickness. A double stone wall can take most of a year before it is ready to finish. Finishing early undoes the work.

Usually not. Australian home policies commonly exclude gradual damage, wear and tear and lack of maintenance, and salt damp falls into that group. A sudden event is treated differently — a burst pipe, for example, is often covered. Read your own policy wording, and ask your insurer before you assume either way.

Yes. Building work in South Australia is licensed by Consumer and Business Services (CBS). We only refer specialists who hold the licence their work needs. You can ask for the licence number and check it yourself on the CBS register. A legitimate operator will not mind.

Yes. A building inspector will normally find it, and a buyer will ask for a price reduction or walk away. A written assessment is useful either way. If you are selling, it shows what the real problem is and what it costs. If you are buying, it stops you guessing at a number.

It matters a great deal, and it is often mistaken for damp. Reactive clay swells when wet and shrinks when dry. That movement cracks walls and footings. A crack then lets water in. So the two turn up together, but they are different problems with different repairs. An assessment should tell you which one you are looking at.