Why we argue ourselves out of work

Thirteen things that get called rising damp

Every one of these presents as damp low on a wall. Several of them produce a level line, salt bloom and a high meter reading, which are the three things most commonly offered as proof of rising damp and which none of them prove.

The right-hand column is the whole point of the page.

The eight, and what actually fixes them

These are the ones where the correct answer is a different trade. Indicative Australian ranges are given because a number is the only thing that makes the comparison real, and because the gap between these figures and a whole-house injection is the entire subject of this page.

The commercial logic, stated plainly

A business that sells one treatment and gives away the diagnosis has an arithmetic problem, and it is worth setting it out without any accusation attached, because the mechanism does not require anybody to be a villain.

An inspection costs the contractor a vehicle, a technician and a couple of hours. If it is free, that cost has to be recovered from the jobs that convert. Every visit that ends in you do not need us is a straight loss, absorbed by the visits that end in a sale. Run that model long enough and the conversion rate is not an outcome, it is a budget line. Nobody has to decide to over-diagnose. The incentive does the work.

Now add the instrument. A two-pin resistance meter measures electrical conductivity, and soluble salts are electrolytes, so a dry but salty wall reads as high as or higher than a genuinely wet one. Readings above 100% moisture content are common on salt-loaded masonry - a physically impossible figure that leaves no room for the bricks. The Australian heritage guide's caution is explicit: moisture meters should never be used as the sole basis for diagnosing a damp problem, and never on their own to prove a wall is unacceptably damp. So the free visit arrives carrying the one tool that cannot distinguish the two possibilities that matter most.

Then add the time lag, which is the part that lets the whole arrangement survive. A damp wall does not react quickly. The modelled time to reach 95% of steady height is about 31 days in the standard example, but it scales inversely with evaporation rate, so behind a coating it runs to years. Render a 215 mm wall to 1.25 m and the damp front re-stabilises above the render after roughly 425 days. A treatment assessed at three months has proved nothing whatsoever. The reckoning is deferred by a year to three, not avoided.

And when it arrives, the customer is generally told the salts are historic. Sometimes that is even true, because a chemical damp course genuinely does nothing about salt already above it, which keeps dissolving in humid weather and re-crystallising in dry weather and keeps breaking the masonry down. The heritage guide illustrates exactly that case: brickwork continuing to decay above a chemically injected damp course because the salts were left in place. Its seventh key step exists for that reason.

None of this is speculation about the future. South Australia ran it once already. So many complaints were made to consumer affairs about failed damp treatments that the state government established a Salt Damp Research Committee, which operated from 1974 to 1982. That is the official record, in the state with the biggest genuine salt damp problem in the country.

Why the free inspection is the mechanism, not the perk

We want to be careful here, because free inspections are the market standard rather than a scandal, and a great many decent operators offer them without ever intending to sell anybody anything they do not need.

The problem is structural. The party performing the diagnosis is the party that would perform the cure, and in this trade that party usually specialises in exactly one cure. The national heritage guide addresses this directly. When a homeowner asks which treatment to use, its answer begins by calling that the wrong question, and continues: be aware that many damp-proofing contractors specialise in one treatment method only, so seek independent advice. Its list of dos ends with: do get independent advice, that way there should be no pressure to use a particular product or system.

Professional guidance says the same thing about disclosure. Where a surveyor's recommendations may include sales, the conflict has to be declared so the client understands the survey is separate from the quotation. We have not been able to find an Australian damp contractor who declares it anywhere.

So we declare ours, at the top, in the same size type as everything else. We sell chemical damp-proof courses and epoxy slab barriers. We have a direct commercial interest in you needing one. Everything on this site is written to be checked against published sources rather than taken on our word, and the sources are named so you can check us as easily as you can check anybody else.

The number we are not going to publish

The obvious move on a page like this is a statistic. Some percentage of our inspections end in no damp course recommended, printed large, updated quarterly. It would be the single most persuasive object on the website.

We are not going to publish one, and the reason is the same reason the rest of this page exists. A number like that would be ours. Unaudited, unverifiable, generated by us, reported by us, and free to move in whatever direction our marketing needed in any given quarter. You would have no way to check it. A number you cannot check is decoration wearing the costume of evidence, and this entire site is an argument against exactly that.

What we will publish is the structure, because you can run it yourself. Thirteen causes. Eight that point at another trade. Three more that are still not ours. Two that end in an invoice from us. The rules that separate them are on this page and in the diagnostic, they are deterministic, and the same answers always produce the same result.

And on any job we do take, the things that are usually invisible get written down: drill hole diameter and spacing, hole depth, fluid volume per linear metre, which faces of the wall were treated, sample locations recorded precisely enough to re-sample nearby later, and dated readings. Those are the figures that get quietly reduced under price pressure, and they are the ones that cannot be inspected once the holes are plugged. Publishing them is worth more than a percentage, because you can hold a job to them.

The two cases where the answer is us

It is worth being equally specific about the other side, because a page that only says no is just a different kind of sales pitch.

Rising damp is real. The mechanism is published physics, the model predicts observed heights from measured material properties, and it reproduces field data from Britain to a 4 m thick church wall in Rome showing 5.3 m of rise. Australian conditions make it more consequential here, not less: higher evaporation drives far greater moisture throughput through the same wall, and saline soils mean every litre delivers more salt. The guide's summary is that this produces much higher rates of decay in this country than in the UK. When it is genuinely happening, treating it is the right call and the decay curve gives you a reason not to wait indefinitely.

1. A chemical damp-proof course to external brickworkThe case for it looks like this: solid or cavity brick, generally pre-1950, a level damp line under about 1.5 m, present all year rather than after rain, and a vertical drilled profile showing free water that decreases with height once hygroscopic moisture content has been subtracted. Ground levels already corrected or being corrected as part of the same programme, gutters and plumbing excluded by test rather than by assumption, and the housekeeping monitored over a period the heritage guide sets at a minimum of a year. Correct execution is 10 to 15 mm holes at about 120 mm centres, drilled to within about 30 mm of the far face, gravity fed or injected at low pressure, with the header course drilled by preference on a 230 mm wall or both faces treated where a stretcher course is used.
2. An epoxy moisture barrier to an internal concrete slabThe case for it is narrower and it is a flooring question. New floor covering is going down over a slab that is still passing moisture, confirmed by in-situ relative humidity probe testing to ASTM F2170 at 40% of slab depth, which AS 1884:2021 makes the normative method with acceptance commonly stated at 75% RH unless the flooring manufacturer sets a stricter limit. The slab is ground back to sound clean concrete and an epoxy film is applied so the adhesive and the covering do not fail. It is a negative-side treatment: the water is still under there. It does not fix drainage, ground levels or a missing membrane, and we will say so in writing rather than let it be inferred.
3. What we do not do, and will hand offPhysical damp courses by slot saw or undersetting, undercutting, desalination and poulticing, render removal and replastering, repointing, landscaping and excavation, site drainage and agricultural drains, roof plumbing, general plumbing, subfloor ventilation, and wet-area waterproofing. S&S Remedial are waterproofing and concrete repair specialists, not builders. Where one of those is the right answer - and across the thirteen causes it usually is - we name the trade and stop.
4. What we will not install at allPassive electro-osmosis, which is an earthed copper strip in the wall. Water movement through a porous medium creates the electrical potential, not the other way round, so earthing the resulting charge cannot prevent capillary rise, and the national guide lists it among old treatments that should no longer be considered. Also damp-proof paints and water-repellent coatings on a wall with active rising damp, and hard cement render over a damp wall - all three reduce evaporation, which raises the height of rise, and trap salt at the interface.

What to demand from any damp contractor before you sign

This is the part worth printing. It applies to us exactly as much as to anybody else, and every item on it is drawn from a published standard or a government guide rather than from an opinion about the industry.

None of these questions is aggressive and none of them is unreasonable to answer. A contractor confident in their diagnosis will supply all of it without difficulty, and the ones who cannot are telling you something useful for free.

• Ask who is paying for the inspection, and what happens to that cost if the answer turns out to be that you do not need treatment. It is a fair question and the answer is informative either way.
• Ask them to state in writing whether they are the party who would perform the work. Where the diagnosis and the quotation come from the same visit, that conflict should be on the page rather than in your head.
• Demand drilled masonry samples. BS 6576 requires them. If nobody drilled the wall, nobody diagnosed anything - and that single sentence disposes of a large share of the quotes in this market.
• Demand a vertical profile: six to eight heights up the wall, taken past the last visible sign of damp, with depth intervals at each height, commonly 0-10, 10-20 and 20-40 mm. It is the shape of the gradient that is the evidence, not any individual number.
• Demand hygroscopic moisture content measured at 75% relative humidity and reported separately from total moisture content, so free capillary water can be calculated by subtraction. BRE Digest 245 is built on that comparison, and it is the test that separates you need a damp course from you need the salt removed.
• Demand salt species and percentage by weight where salt is visible or suspected, with about 0.5% by weight as the working threshold for concern. The species also points at the source: nitrate at a sewer, a fertilised bed or a former stable; chloride at groundwater, sea spray or acid cleaning; magnesium sulfate at contaminated bedding sand.
• Demand external ground, paving and garden bed levels measured against the damp course, in millimetres. The code minimums are 150 mm above finished ground, 75 mm above paving that slopes away and 50 mm where a carport or verandah protects the wall.
• Demand a subfloor and cavity inspection. The national guide devotes a whole section to damage caused by the damp-proofing work itself endangering floor timbers below, and requires that both the investigation and the certification of completed works include an underfloor inspection. A borescope also converts a presumed rising damp case into a bridged cavity in about ten minutes.
• Demand that gutters, downpipes, stormwater, plumbing and wet areas were assessed and excluded, with the exclusion tests named rather than assumed. Meter isolation, flood testing, dye testing and CCTV are the tests; none of them is a glance from the driveway.
• Demand the prerequisites sequenced ahead of the injection line rather than after it, and ask directly how the guide's instruction is being handled - do not insert any form of damp course until the basic housekeeping measures are complete and their effectiveness assessed over at least a year.
• Demand the injection specification as numbers: hole diameter of 10 to 15 mm, spacing of about 120 mm, depth to within about 30 mm of the far face, gravity feed or low pressure, and fluid volume per linear metre stated as a figure. Injection above about 1000 kPa is a defect, not a feature - it blows out weak mortar and causes viscous fingering, where the fluid races ahead in fingers and leaves untreated gaps.
• Demand to know which faces are treated. On a 230 mm one-brick wall the header course should be drilled by preference; where a stretcher course is used, the stretchers on the other side must also be treated. Treating one face of a wall that needed both leaves half a barrier and it looks identical from the street.
• Demand the product name and its active-ingredient content, not the word silane. Active content varies from around 15% to around 80% between certified products, and low-strength formulations have still obtained certification.
• Demand desalination in the scope wherever salt exceeds about 0.5% by weight, and ask what happens to the salt if it is not there. Injection can also displace saline moisture upward into masonry that was previously undamaged, which is why a poultice should be applied at the same time as the injection rather than afterwards.
• Demand a drying period before finishing: typically 3 to 6 months, up to 12 on thick walls, and no wallpaper for at least 12 months. A room handed back next week is a scheduling promise, not a technical one, and repainting early makes bubbling close to certain.
• Demand the guarantee's exclusions as an actual document before you ask about the number of years. Read specifically for blocked gutters, a garden bed rebuilt against the wall, extensive repointing over the treated course, a sealer applied to the wall face, and condensation. Several of those conditions are entirely reasonable maintenance obligations - the problem is finding out about them afterwards.
• Check the licence number on the QBCC public register before you sign anything. Building work in Queensland above a dollar threshold, commonly stated as $3,300 including materials and GST though you should confirm the current figure with the QBCC, requires a licensed contractor and triggers Home Warranty Scheme insurance.
• Treat a per-metre rate well under about $100 as a question rather than a saving. The guide names the two mechanisms in print: diluting the fluid with additional solvent, and spacing the drill holes wider than recommended. A third is treating one face of a wall that needed both. All three are invisible the moment the holes are plugged, and nobody can inspect the result afterwards - not you, not a building inspector, not us.
• Ask one final question, and listen carefully to the answer: what would you tell me if it turned out not to be rising damp, and what would you recommend instead? A contractor who has thought about the other twelve possibilities will have an answer ready.

Where this leaves us

We are a waterproofing and concrete repair specialist, not a builder, and we perform two treatments. When one of those two is genuinely the right answer we would very much like the job, and when it is not, saying so costs us a sale we were never entitled to.

There is a version of this trade where the meter is the method, the survey is free, the answer is always the same answer, and the guarantee quietly excludes the thing that was actually wrong. We would rather be a different version, and the only way to demonstrate that is to publish the working - the causes, the tests, the numbers, and the eight outcomes at the top of this page that end with somebody else's phone number.

If you are holding a quote and this page has made you uneasy, that is a reasonable place to be. The checklist above works on any contractor, and it works on us. Use it.

What it costs

Questions we actually get asked

Why would a damp company tell me I do not need a damp course?

Because we charge for the diagnosis rather than giving it away, which removes the cost of saying no. An inspection that is free has to be paid for by the jobs that convert, so every visit ending in you do not need us is absorbed as a loss by the visits that end in a sale. Nobody has to decide to over-diagnose under that arrangement; the incentive does the work on its own. Charging for the investigation makes the recommendation the same amount of work whether the answer is a damp course, a downpipe or a data logger. The obvious counter-argument is that you are being asked to pay for something several other operators will do for nothing, and that is a fair thing to weigh.

You must turn away a lot of work. How much?

We are not going to put a percentage on it, and we would rather explain why than invent one. Any figure we published would be generated by us, reported by us, impossible for you to audit, and free to drift in whatever direction our marketing needed. A number you cannot check is decoration. What we publish instead is the structure, because you can run it yourself: thirteen causes in the diagnostic, eight of them pointing at another trade entirely, three more that are still not ours, and two that end in an invoice from us. The rules that separate them are deterministic and they are set out in full on this page.

My inspection was free and they found rising damp in twenty minutes. Does that mean it is wrong?

No, and it is worth resisting the urge to conclude that. Experienced people read patterns quickly, and a level damp line at the base of a pre-1950 brick wall that is present all year really is the pattern. What twenty minutes and a surface meter cannot do is exclude the alternatives or establish that the water is free capillary water rather than moisture that salt has pulled out of the air. Those require drilled samples, a vertical profile, and hygroscopic moisture content measured at 75% relative humidity and reported separately. So the finding may well be correct. It is the evidence behind it that has not been gathered yet, and that is what you would be signing against.

I already paid for injection and the wall is still crumbling. What happened?

Most often a scoping failure rather than a product failure, and it is one of the more predictable outcomes in this trade. A chemical damp course stops water rising. It does nothing at all about the salt already in the wall above it, which keeps dissolving in humid weather and re-crystallising in dry weather, and every cycle breaks the masonry down a little further. The Australian heritage guide illustrates exactly this case - brickwork continuing to decay above a chemically injected damp course because the salts were left in place - and its seventh key step exists because damp course insertion alone is not enough. The test that settles it is a drilled profile with hygroscopic moisture content reported separately. If free water is now negligible and salt content is high, your damp course is working and salt is the remaining problem, which is a different scope and a different trade from another round of injection.

What if more than one of the thirteen is happening at once?

That is common, and it is the main reason the sequence matters more than the diagnosis. A blocked downpipe, a buried damp course and a shower membrane failing on the other side of a wall can all be running at the same time, and each one will happily take the credit for the others' symptoms. The published method deals with it by ordering the work rather than by choosing a winner: correct the water sources first, then monitor. The national guide builds in a review of at least a year before proceeding to damp course insertion, specifically to account for storms, floods and drought moving the readings in both directions. It is also why a treatment judged successful after three months proves nothing - the modelled lag behind a coating runs to years, not weeks.

Is a paid inspection just another way of charging me?

It is a way of charging you, yes, and it should be judged on what it produces. A defensible investigation involves drilled samples at multiple heights and depths, laboratory oven-dry moisture content, hygroscopic moisture content at 75% relative humidity, salt speciation where salt is suspected, ground levels measured against the damp course in millimetres, a subfloor and cavity inspection, and drainage and plumbing excluded by test. Independent specialist investigation and reporting runs $600 to $2,000 in published Australian ranges, with laboratory analysis adding roughly $400 to $1,500. Set that against a whole-house chemical damp course at $3,500 to $15,000, and against the possibility that the actual answer costs $500 to $6,000 and belongs to a landscaper.

Can I use your checklist on you?

Please do, and it is the reason it is written the way it is - every item cites a standard or a government guide rather than an opinion, so it works on anybody including us. If we cannot supply drill spacing, hole depth, fluid volume per linear metre, which faces of the wall were treated, sample locations and dated readings, then we have failed our own test and you should say so. The only thing we would ask is that you apply the same list to every quote you are holding, because a checklist applied to one contractor and not the others is not a comparison, it is a preference.