Rising damp questions, answered

Because that is what the tool can honestly establish. A building inspector uses a surface meter, which measures how well the wall conducts electricity. Old salt in a wall conducts even when the wall is dry, so a salty dry wall reads as wet. The inspector is not being vague. They are reporting exactly what their method can show, and a proper diagnosis needs a different test.

It takes up to two hours. Moisture is measured at intervals up the wall, not at one spot, because rising damp makes a curve that is wettest at the base. A sample is drilled from the mortar behind the plaster and tested for its real moisture content. The outside is checked too: ground levels, paving, garden beds, reticulation and weep holes. You get a written finding that names the cause.

No. That is the assessment and the written diagnosis only. Any treatment is quoted separately after someone has seen the wall, and you are free to take that quote elsewhere. We charge the assessment fee because a free inspection is only ever free if it ends in a sale, and that is the wrong incentive when four of the five likely answers are cheap.

In Perth, often yes. A WA inspection firm reports that what it finds week to week is mostly lateral damp, not rising damp. Sand soil and double brick let water travel from a sprinkler, a raised garden bed or a path straight through to the inside wall. It looks identical. The fix is usually far cheaper.

It almost always makes it worse. Sealing the face does not stop water entering the wall, it stops it leaving. The moisture then rises higher or moves along to find somewhere to evaporate, and the salt builds up behind the coating until the render lets go. Undoing a sealed wall is a common Perth job and it is not free.

Limestone is porous and many older Perth and Fremantle walls were built with no damp course at all. It takes up groundwater readily and it takes injection differently to brick, usually needing more of it. A cement render on limestone traps the moisture and the stone decays behind it, so the render often has to come off before anything else is worth doing.

No. It stops water climbing. A wall that has been wet for years holds a lot of water and it leaves slowly, over months. It also does not remove the salt already in the masonry, and salt is what blows the render and stops paint holding. A proper specification deals with the render separately, and that is often the bigger half of the bill.

Usually not. Most home policies exclude gradual deterioration, and rising damp is gradual by definition. A sudden burst pipe that soaked a wall is a different matter. Read your own policy or ask your insurer, because we cannot tell you what your cover says.

Not us. We are a referral service. We arrange the assessment with an independent damp specialist registered with the Building Services Board, and they do the work and carry the licence and the insurance. We never claim to be the contractor.

No, and it is one of the most common false alarms in Perth. Bore water leaves an orange or brown iron stain on walls, paths and fences, usually in a spray pattern from a sprinkler. It sits on the surface. Rising damp leaves a level tide line low on the wall with salt below it, and it is there all year.

Not if the cause was found and fixed. That is the whole reason the assessment comes before the quote. An injected damp course in a wall whose real problem was a paved garden bed will fail, because nothing about the wall changed. Fix the cause first and the barrier lasts.

Persistent damp encourages mould, and mould can affect people with asthma or allergies. We are not medical people and we do not give health advice. If someone in the house is unwell, speak to a doctor. What we can do is find out why the wall is wet.

They do, and the older ones get it badly. The ingredients are porous limestone or brick, no damp-proof course, and ground that holds water through winter. Fremantle, Subiaco, Mount Lawley and the river suburbs have all three.

No. That seasonal pattern is the signature of rising damp in Perth, because it tracks the water table. Summer hides it; it does not fix it.

Almost certainly not. Iron-rich bore water from reticulation stains walls orange from the outside. It is cosmetic. Rising damp comes from inside the wall and carries salt, not iron.

Usually a cement render or a plastic paint applied over limestone. Limestone has to breathe. Seal it and the moisture rises higher and pushes the coating off, which is exactly what you are seeing.

You can buy the kit. The reason it usually fails is that the diagnosis was wrong, or the salt already in the wall was never removed, so the tide-mark returns through the new plaster. The chemical is the cheap part.

Building work in Western Australia is regulated by the Building Services Board, and we only refer specialists holding the registration appropriate to the work. Ask to see it — a legitimate operator will not mind.

The physical work is usually a few days. The wall then dries for months. Any finish applied before it has dried will fail, which is why the sequence matters more than the speed.