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Moisture Meter – Useful Guide

Moisture Meters

Moisture Meter – Types

We mentioned in our article detailing some of the Leak Detection equipment we use how moisture meters are an essential piece of equipment for a number of reasons. People sometimes refer to them as damp meters, but for the purposes of this article, lets assume we are talking about the same thing when we use the term ‘moisture meters’.

Separately to this article we have talked about moisture meter readings from the air, especially relative humidity (RH), Grams Per Kilo of moisture (GPK) and temperature. Collectively these are given the name psychometric readings. To find out more about these see our guide to Relative Humidity and our Dew Point Calculator, which helps to understand why moisture collects on surfaces, including with things such as condensation problems in your home, which can lead to mould problems. An infrared thermometer can be useful alongside this.

We have written a separate article about room temperature and humidity, to run a test on how it varies in different parts of the same room according to location and height. We also looked at how humidity in houses is linked to outdoor conditions. The results are interesting.

Moisture Meter Readings
Moisture Meter Readings – Relative Humidity.

In this article we will be looking at moisture meters readings of the materials in a property, in particular wood moisture meters, concrete moisture meters, plaster / plasterboard moisture meters and relative readings for moisture meters. It’s a powerful tool for hidden water leaks. On the subject of plasterboard, we have a really interesting article about Moisture Resistant Plasterboard.

Every property is different, as is every leak. We tailor our leak detection service according to these factors, including the materials the property is constructed of and especially those affected by a leak. As you might expect, finding and fixing a leak in a Georgian Mansion is very different to looking for a leak in a modern Penthouse flat! As well as domestic water leak detection, we also offer a full commercial leak detection service for businesses too. Thankfully, we have moisture meters, and other leak detection equipment, for every occasion.

Moisture Meters and Water Leak Detection

It sounds obvious but with a water leak comes water and being able to detect changes in moisture can be a very powerful part of finding water leaks in properties. They can see what the human eye cannot, are highly sensitive to small changes in moisture in a material and calibrated. In fact, we don’t use one moisture meters in leak detection, we use a variety.

Although moisture meters often have the ability to carry out many functions (some do only one thing), generally they don’t do everything and this is where specific, specialist moisture meters come into play. In this article we will look at moisture meters that

Non Destructive Moisture Meters

As we have said before, when carrying out our leak detection surveys, we try as much as possible to use non-destructive methods to find water leaks, including with moisture meters, but this this can also include the following:

But non-destructive methods also includes damp and moisture meters. People often think of pinned tools when it comes to moisture meters, tools where you effectively push two prongs into a material such as wood or plaster. However, many moisture meters do not rely on pins, they are sometimes referred to as pinless moisture meters. You can understand how pins would possibly struggle with measuring moisture deep into concrete materials!

The image below is an indication of how a pinless moisture meter works.

How a Pinless Moisture Meter Works
How a Pinless Moisture Meter Works

Moisture Meter – Concrete

A common material often affected by water leaks, especially in more modern properties, is concrete. Concrete is generally a porous material (unless it has been treated or coated) which absorbs moisture like a sponge. It can often be a material in which, for example, copper pipes run to feed your hot or cold water, or pipes for central heating systems. We look for them when looking for central heating leak detection, for example when people have a persistent F1 boiler error or radiator leaks.

So for this job, there are bespoke concrete moisture meters, which work a bit like the image above, sending signals across a number of pins (surface ‘sprung’ pins not embedded ones!). They take readings for moisture content of the concrete using non-destructive methods, which allows our leak detection engineers to check for variances in moisture within the material vs known normal ‘dry’ levels and control readings. You will notice we say ‘dry’ because concrete does naturally have a level of moisture within it, even when it looks dry and cured.

As you can see from the image below, it shows an example Tramex CME5 Moisture Meter which uses electrical impedance readings to pick up moisture in concrete. It gives an instant reading on concrete and screed materials too. It is a popular moisture meter.

Tramex Concrete Moisture Meter
Tramex CME5 Concrete Moisture Meter

Moisture Meter – Plaster

Another very commonly found material in UK properties, is plaster and plasterboard. When we are looing for ceiling leaks and a leak or damp on walls we would usually use a different type of moisture meter than the one shown above. That said, there are moisture meters such as the Tramex CMEX II or Tramex CMEX5 etc which can do both.

When looking for elevated moisture in or behind a plastered surface, both pinned and pinless moisture meters can be used. Even the pinned moisture meters are only minimally ‘destructive’ and help to get a reading with a material. This can be done at different depths according to the pins uses and how deep you are looking, it’s a bit chicken and egg.

Moisture in plaster in properties is particularly a concern as it can deform, ‘de-bond’ (come away from the material it is adhered to) but also, it can cause black mould to grow. Plaster and plasterboard is one of the materials mould grows on, in fact it’s a very common place to find mould and that is not always immediately visible. If there is moisture behind or in a plasterboard stud wall for example, the mould can grow on the back of the material, not seen initially.

Just as we said with concrete, plaster has a natural / stabilised level of moisture in it so we look for elevated readings with moisture meters and, wherever possible take control readings for comparison.

When taking readings on plaster, normally Moisture Content (MC) or Wood Moisture Equivalent (WME) moisture meter readings are used (although relative readings can be useful too – with the right tool). As you can see on the Protimeter MMS2 Moisture meter below on the right, there is a reading of 100%, which means the plaster is soaked or saturated, clearly not good.

Moisture Meter - Plaster and Plasterboard
Moisture Meter – Plaster and Plasterboard

Moisture Meter – Wood

As we have said with other materials in this article, wood is a very common material found in properties and is used commonly in the structure including in walls, floors and ceilings. So as you might expect, when we are looking for leaks in those places, including a leak under floorboards it is also a place where moisture meter readings are taken.

Wood is a very interesting material to take moisture meter readings in (most commonly WME – Wood Moisture Equivalent) because how much moisture is present will vary according to the type of wood, where it is located and what it is coming into contact with (including a water leak!). So again, we are very careful to be aware of this. We explain this further in our article about damp meter readings.

That said, looking at the readings below from the detachable pin readings on the Protimeter MMS2 shown below, 99.4% is certainly an abnormally high reading showing elevated levels.

Mositure Meter - Wood
Mositure Meter – Wood

The other thing to consider when it comes to wood in particular when finding water leaks is that prolonged exposure to moisture can cause wood to rot and become weakened, which is clearly of concern given that, as we said above, wood is often structural.

As you can see from the image below of a floor exposed to moisture for a long time, it lost all of its structural integrity from long exposure to moisture…

Floor Damage - Damp and Rot
Floor Damage – Damp and Rot

So as we always say on this site – if you have a water leak, or think you do, do not ignore it. If left alone it will likely cause more damage to your property over time! Get help from a professional such as ourselves.

Moisture Meters – Relative Readings

One of the things we have talked about in this article on moisture meters is ‘Relative Readings’ (which are sometimes abbreviated to ‘REL’ readings. But what are REL readings?

Well it’s not that straightforward as it will depend on the specific moisture meter and the material being measured. Also, relative readings are often used when looking for moisture under surfaces, so say you are looking at a bathroom leak under tiles the readings is effectively looking at the tiles, grout and possibly wood or concrete below. Either way, to keep this simple, the key thing is in the name ‘Relative’ moisture meter readings are looking for abnormal variances in moisture in or under materials.

So for example, using our example above, if you are looking under tiles for a leak, you don’t want to lift the tiles up and cause damage to find it just so you can stick pins in some wood! You want to be able to detect the moisture without doing that, that is where relative moisture meter readings are very useful. You might get a situation where across a floor or wall where the readings are fairly consistent but then you get a much higher reading, that can indicate a water leak nearby.

In situations like that, we would likely use other methods of detection like those mentioned earlier in the article to help collect more evidence. If (and it is an if) we need to lift a flooring such as tiling to get to a leak we want to collect as much evidence as possible to indicate a leak before accessing it – this is where the ‘access’ part of Trace and Access comes in. Leak Detection is the trace and ‘access’ is, as the name says, accessing it.

We have a more detailed guide on Trace and Access Leak Detection, including the stages we go through to maximise the chances of finding your leak.

We demonstrate how to see moisture under tiles in our article about pinless moisture meters, further down that page you will see a real demonstration we setup which shows clear results.

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WaterLeak.co.uk logo

Moisture Meters and Water Damage

The final thing to talk about with moisture meters is their role in Water Damage Restoration work after a water leak has been found and fixed. As we said earlier, with water leaks you obviously get (unwanted) water in your property which then increases the moisture in materials in the fabric of your building. Clearly, after you have had a leak, you need to repair and dry your property back to normal pre-incident conditions for that property, what we call stabilising.

As you might expect, moisture meters can play an important role in that process. Over time they can be used to take readings to compare to the elevated ones seen with the leak and to track the drying process progress. In particular focusing on (a) not over-drying the property and (b) getting it back to levels expected for that property, which is where control readings come in. Moisture meter control readings can be taken in unaffected areas for comparison, to help compare the area you are drying to the affected areas. That is assuming that the materials are not replaced, which can happen.

Water Damage Repairs
Water Damage Repairs – Services

As well as doing Water Leak Detection work, we are experienced in all aspects of water damage restorations. So as well as helping you find your leak, we can help restore your property after a water leak, or even after flooding. We can work with you and your insurance company, if you want, and produce insurance grade reports for your insurance company.

Rainbow International is the UK’s biggest water damage management company and we work with many of the biggest insurance companies in the UK to provide these services. They trust us to carry out this work for their customers. So if you need help with a water leak or any other damage management work, get in touch with our friendly team today and we’ll be glad to help.

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