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Pinless Moisture Meter – Best Option?

Pinless Moisture Meter

Non Invasive Moisture Meters

Whenever we are doing water leak detection surveys at a property, we use a wide array of leak detection equipment, and that includes moisture meters (or damp meters as they are sometimes called). These allow us to do moisture mapping. A subset of these moisture meters are pinless moisture meters or non-invasive moisture meters as they are often called – remembering that some moisture meters are capable of pin and pinless moisture meter methods of finding leaks and damp etc.

Damp Meter
A selection of the best damp meters.

What is Moisture Mapping?

Moisture mapping is the practice of taking moisture readings across the various surfaces and materials in a property and comparing them vs each other and vs control measures of the same material in close by areas (for comparison). This is often done using pinless moisture meters.

Clearly it is important to remember that different materials will have different natural / regular levels of moisture, which will also depend on the ambient conditions they are kept in. For example, moisture levels of plaster will be different to to wood, concrete and bricks for example. On top of this, there are specific measurement scales for different materials – such as WME (Wood Moisture Equivalent).

The aim of all this is to check for elevated moisture either as part of a damp survey or leak detection survey. It is also used to see how a property is drying back to normal after water damage restoration from a water leak or flood.

Remember, such pinless moisture meters are expensive, professional and calibrated pieces of equipment. All our leak detection engineers are trained in both using them to best effect but also to understand the readings, especially when considering the different types of material.

Moisture mapping often plays a big part in understanding damp on walls.

What is a Pin Moisture Meter?

A pin or pinned moisture meter usually has pins directly on the meter or a separate pin probe which is used to take moisture readings in a material. A current is passed between the pins on the probe an this is used to feed into the moisture meter which gives a reading of the moisture present in the material.

Here is an example of a pin moisture meter reading being taken on plaster…

Damp Meter on Wall
Checking for Damp

What is a Pinless Moisture Meter?

A pinless moisture meter works on a somewhat similar basis, however, instead of using pins to take readings, the meter usually transmits and reads penetrative signal readings via pads on the moisture meter. These are non-destructive, usually relative, readings to show variances across a range. The diagram below helps to demonstrate this.

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

The principle is the same, checking for elevated moisture, which can be a sign of a water leak. When doing water leak detection, these help to refine possible areas for water leaks. If an area is suspected as having a leak, other leak detection technology such as acoustic leak detection (using acoustic listening devices), thermal imaging leak detection and pipe detectors are used to collate additional evidence before trying to access the leak and repair it. In some instances, tracer gas leak detection is also carried out.

Underground Water Leak
Underground Water Leak

Clearly this is very useful for finding an underground water leak, a water leak under floorboards or water leak in ceilings. Clearly when finding leaks in these places, non-invasive leak detection is definitely preferential so as not to cause damage to your property which we only do if absolutely necessary to trace and access a water leak or to repair it.

Pinless Moisture Meter Demonstration

We setup a test to demonstrate how pinless moisture meters work, using a Tramex MRH3 Moisture Meter on this occasion, one of the moisture meters our leak detection specialists use.

To setup this demonstration, we took a small towel and dipped the end of it in water on the right hand side of it (see image below)

Damp Towel
Damp Towel (on Right Hand Side only)

We then covered it with a ceramic tile commonly seen bathrooms or kitchens…

Damp Under Tiles on Floor
Damp Under Tiles on Floor

Clearly in this situation, a pin probe on a moisture meter would not be able to penetrate to where the moisture is, so a non-destructive moisture meter reading is needed, comparing relative readings across the tile. As you can see below…

Comparative Moisture Readings
Comparative Moisture Readings – left (Dry) and Right (Wet).

Clearly the reading on the left (at 37) is much lower than the right hand end (60) where the wet end of the towel is. The same principle applies to if you were trying to find wet plaster or floorboards below. You can quickly see the wetter areas underneath the tiles. To show this is the case, we lifted the tile and took pin moisture meter readings.

Pin Probe Moisture Readings
Pin Probe Moisture Readings – left (Dry) and right (Wet)

Clearly this would not normally be possible without lifting the tile (probably breaking it). This is where pinless moisture meters really come into their own across a number of materials.

To help demonstrate the versatility of this particular Tramex Moisture Meter, here it is taking readings with a humidity probe – so not only is it a pinless moisture meter, it is a pin moisture meter and a humidity / air moisture meter, very versatile!..

Moisture Meter Readings
Moisture Meter Readings – Relative Humidity.

The readings on that display from the pinless moisture meter are:

  • RH – Relative Humidity (82% on this occasion)
  • T – Temperature in the room (14°C)
  • Td – Dew point (11.6°C in this room)
  • gms – Absolute Humidity in Grams Per Kilo of air (8 GPK)

If you want to understand more about these we have a page on different moisture meter readings we also have a more in-depth page explaining all about relative humidity too. We also have our own quick dew point calculator to give an indication of what the dew point in a room is. An infrared thermometer can be useful here too.

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WaterLeak.co.uk logo

If you need help with a water leak or damp problem, get in touch today.