Damp is the single most argued-about thing in the UK building trade. A homeowner sees a tide mark and hears “rising damp”. A plasterer sees the same wall and knows it is a failed gutter. Somewhere between the two, someone has to produce a number – and that number comes off a moisture meter.
Get the meter right and you can walk into a job, find the wet, prove where it stops and price the work with confidence. Get it wrong and you are either chasing damp that is not there or missing a leak that will come back through the customer’s new emulsion in six weeks. This is a piece of kit where the cheap end genuinely does lie to you, so it is worth understanding what you are buying.
Quick Verdict
For anyone doing damp work seriously – surveyors, damp specialists, restoration, dilapidations – the Protimeter Surveymaster 2 (BLD5365) is still the default at roughly £400-£450 including VAT. It does pin and pinless in one body, everyone in the industry recognises the readings, and it is the meter that ends arguments on site.
If you are a builder, plasterer or plumber who needs to check a wall a few times a year, the Protimeter Mini BLD2000 at around £180-£195 gives you the same trusted pin readings without the pinless head. And if you just want a rough go/no-go check before you plaster, a Dryzone or Magnusson meter for £20-£35 will tell you “wet” or “dry” perfectly well – as long as you understand it will not tell you much more than that.
Pin or Pinless – The Decision That Matters Most
Almost every complaint about moisture meters comes from someone using the wrong mode for the material. The two technologies measure completely different things and neither is universally better.
Pin (Resistance) Meters
Two pins go into the material and the meter measures electrical resistance between them. Wet material conducts better, so lower resistance reads as higher moisture. Pin meters are the ones with the pointed probes and they give you a reading at a specific depth and a specific spot, which is exactly what you want when you are mapping how far up a wall the damp actually goes.
In timber, a pin meter reads genuine moisture content as a percentage and it is accurate enough to be used commercially – joiners use them to check kiln-dried stock is actually at 8-12% before it goes into a heated house. In masonry and plaster the reading is not a true percentage, it is a Wood Moisture Equivalent (WME) scale, and it is affected by anything else that conducts. Salts are the big one. Hygroscopic salts left behind in old plaster will read soaking wet on a pin meter when the wall itself is bone dry, which is how a lot of unnecessary damp-proofing gets sold.
The other downside is obvious: you are putting holes in someone’s finished wall. Small ones, but visible on paintwork and unacceptable on wallpaper or a heritage finish.
Pinless (Capacitance) Meters
A pinless meter presses a flat sensor pad against the surface and reads moisture through the material using a radio-frequency field, typically to a depth of 20-30mm. Nothing gets punctured, and you can sweep a whole wall in seconds looking for the wet patch rather than guessing where to stick pins.
The catch is that pinless meters read everything in that 20-30mm zone. Foil-backed plasterboard, embedded cables, metal lath, pipes, dense concrete blocks and even a wet screed under a dry floor finish will all skew the reading. Pinless is a search tool – brilliant for finding where the moisture is, less reliable for saying precisely how wet it is.
Which is why the professional answer is both. You sweep with pinless to find the boundary, then confirm with pins and, on a proper damp investigation, with a hygrometer or deep wall probes.
At a Glance – Moisture Meters Compared
The table below covers the meters most UK tradespeople actually end up buying. Prices are typical street prices including VAT and move around, so treat them as a guide rather than a quote.
| Model | Type | Best for | Approx. price |
| Protimeter Surveymaster 2 (BLD5365) | Pin + pinless | Damp surveys, dilapidations, restoration | £400-£450 |
| Protimeter MMS3 (BLD8800) | Pin + pinless + hygro | Full professional damp diagnosis | £950-£1,150 |
| Protimeter Mini (BLD2000) | Pin only | Builders and trades needing trusted readings | £180-£195 |
| Protimeter Aquant (BLD5765) | Pinless only | Non-marking surveys, finished surfaces | £250-£290 |
| Trotec BM31 | Pinless only | Fast sweeping, screed and floor checks | £70-£95 |
| Dryzone Moisture Meter | Pin only | Budget trade go/no-go checks | £25-£35 |
| Magnusson Moisture Meter | Pin only | Occasional use, van glovebox spare | £20-£25 |
The Best Moisture Meters for 2026
Best All-Round Professional: Protimeter Surveymaster 2 (BLD5365)
This is the industry standard and it has been for a long time, which matters more than it sounds. When you put a Surveymaster reading in a report, the other side’s surveyor knows exactly what instrument produced it and how it behaves. That is worth real money in a dispute.
You get a pinless search mode reading to around 19mm, a pin mode with the calibration check built in, and a socket for deep wall probes and a hygrometer hood if you go further down the damp-diagnosis route later. The colour-coded green/amber/red display means you can show a customer the screen and they understand it without a lecture.
Weak points: it is not cheap, the pinless depth is shallow compared with some rivals, and the case is functional rather than tough – it does not enjoy being thrown in the back of a van with a breaker. At roughly £400-£450 it only makes sense if damp is part of what you sell.
Best Top-End: Protimeter MMS3 (BLD8800)
The MMS3 adds proper hygrometry – relative humidity, temperature, dew point and specific humidity – to the same pin and pinless functions. That is the difference between saying “this wall is wet” and saying “this wall is wet because the room’s dew point is being hit every night on that cold external corner”. For condensation and mould cases, that distinction is the whole job.
It also logs and exports readings, which saves an enormous amount of time if you write formal reports. At £950-£1,150 it is a business purchase, not a tool purchase, and it is genuinely hard to justify unless surveying is your income.
Best Value Pin Meter: Protimeter Mini (BLD2000)
If you want Protimeter accuracy without the pinless head, this is it. Same pin electronics, same WME scale, same colour-banded display, same recognised name on the report – in a smaller body at around £180-£195 including VAT.
For a builder, plasterer or plumber this is the sweet spot. You are almost always confirming a specific spot rather than searching a whole elevation, and pins do that better anyway. It is also the meter to buy if you have been burned by a cheap unit giving you readings you did not trust.
Best Non-Marking: Protimeter Aquant (BLD5765)
Pinless only, deeper sensing than the Surveymaster’s search mode, and no holes at all. This is the meter for finished properties, listed buildings, wallpapered rooms and anywhere the client would notice pin marks – which in dilapidations and lettings work is most places.
Around £250-£290. Understand the limitation before you buy: without pins you cannot confirm a reading or profile depth, so it is a searching instrument rather than a diagnostic one. Most people who own one also own a pin meter.
Best Budget Pinless: Trotec BM31
Trotec make sensible instruments at sensible money and the BM31 gives you fast non-destructive sweeping for around £70-£95. It is genuinely useful for checking screed and floor slabs before laying, tracing a leak across a ceiling, or getting a feel for a wall before you commit to pins.
It is not going into a formal report and it should not be. Treat it as a search tool that saves you an hour of guessing, and it earns its money quickly.
Best Cheap Trade Meter: Dryzone Moisture Meter
At £25-£35 the Dryzone is the one to buy if you want something better than the supermarket tat but cannot justify a Protimeter. Simple pin meter, clear LCD, sensible calibration for masonry and timber, and it comes from a company that actually sells damp-proofing products so they understand the application.
Use it as a go/no-go: is this wall dry enough to plaster, is this timber dry enough to fix. Do not use it to diagnose the cause of damp or to argue with a surveyor.
Best Glovebox Spare: Magnusson Moisture Meter
Twenty quid from Screwfix, lives in the van, saves the day about twice a year. Pin type, reads timber and masonry, runs on a 9V battery. It will tell you whether a floor is wet before you lay laminate over it, and that is worth the money on its own.
Do not expect precision, do not expect it to survive being sat on, and do not quote its readings to anyone.
Buyer’s Guide – What Actually Matters
Understand WME Before You Trust Any Reading
On timber, a pin meter reads true moisture content. On brick, plaster, screed and concrete it reads Wood Moisture Equivalent – the moisture content that timber would have if it were in equilibrium with that material. It is a comparative scale, not an absolute one. A reading of 20% WME on plaster does not mean the plaster is 20% water. What it means is “considerably wetter than the dry material next to it”, which is exactly the comparison you want when you are mapping a damp patch.
This is why professionals take a baseline reading on known-dry material in the same room before they start. Without that comparison the number on the screen is close to meaningless.
Salts Will Fool a Cheap Meter Every Time
Hygroscopic salts – nitrates and chlorides that migrate out of masonry over decades – conduct electricity beautifully and attract moisture out of the air. A pin meter on old salt-contaminated plaster can scream wet on a wall that is completely dry structurally. Any meter under about £50 will do this and give you no way of knowing.
The professional answer is a carbide test or a deep-wall probe reading at masonry depth, well behind the contaminated plaster. If you are being asked to price a damp job on the strength of a surface reading alone, you are being asked to guess.
Calibration Checks
Every serious meter has a way to verify it is reading correctly – the Protimeters have a calibration check block or built-in check function. Use it at the start of any job that might end in a report. It takes ten seconds and it is the first thing anyone will ask you about if your findings are challenged.
Pair It With a Thermal Camera
A moisture meter tells you a spot reading. A thermal camera shows you the shape of the whole problem in one image – the cold plume of an evaporating damp patch, the track of a leaking pipe under a floor, the missing insulation causing the condensation. Used together they are far more powerful than either alone: the camera finds it, the meter proves it.
If you are building a damp-diagnosis kit from scratch, a Protimeter Mini plus a decent thermal camera will out-perform a top-end meter used on its own.
Frequently Asked Questions
What moisture reading is safe to plaster or paint over?
As a working rule, most plasterers want masonry below about 16-18% WME before skimming, and you want fresh plaster reading dry and stable before decorating – typically around 10-12% WME and, more importantly, not falling any further over a couple of days. Take the reading, wait 24 hours, take it again. A number that is still dropping means the wall is still drying.
How dry does timber need to be?
For internal joinery in a heated house, 8-12% moisture content. For external timber and framing, 14-18% is normal. Anything fixed in above about 20% will shrink, cup and open up its joints once the heating goes on, and the customer will blame your workmanship rather than the timber merchant.
Are pinless meters accurate enough for a survey report?
On their own, no. They are affected by density, foil backings, embedded metal and anything wet below the surface layer you are testing. Use pinless to locate and pins or deep probes to confirm, and record which method produced each reading in the report.
Is a £20 moisture meter worth buying at all?
Yes, for a narrow job – telling you whether something is obviously wet or obviously dry before you commit to a floor covering or a coat of paint. It is not worth buying if you need to know how wet, how far the damp extends, or why it is there.
Can a moisture meter diagnose rising damp?
No meter diagnoses a cause – it measures a condition. High readings at low level that fall off sharply above about a metre are consistent with rising damp, but they are equally consistent with a failed gutter, a bridged cavity, raised external ground levels or a leaking waste pipe. The meter narrows it down; you still have to go outside and look at the building.
Do I need to calibrate a moisture meter?
Professional meters need a calibration check before use rather than a full recalibration – the check block or built-in function confirms the electronics are reading true. Cheap meters generally have no calibration facility at all, which is another reason not to lean on their numbers.
The Verdict
If damp is part of how you earn, buy the Protimeter Surveymaster 2. The pinless-then-pins workflow is how the job is actually done, and the name on the meter carries weight when your findings get challenged. Add hygrometry with the MMS3 only if you are writing formal reports for a living.
For everyone else, the Protimeter Mini is the honest recommendation. It gives you readings you can stand behind at a price a working trade can justify, and it will still be doing it in ten years. Keep a Dryzone or a Magnusson in the van as a quick check and you have the whole job covered for well under £250.
Whatever you buy, take a baseline reading on dry material first, treat masonry numbers as comparative rather than absolute, and remember that salts make cheap meters lie. The meter is evidence, not a verdict.
Prices correct at time of writing and will vary by retailer. Always confirm current pricing and specification before ordering, and check that any instrument used for formal reporting has a valid calibration check.
