Internal wall moisture reading

SteelChair

I bought one of the 2 pin wall moisture meters/detectors.

I am using it on an internal plasterboard painted wall.

Any one else done this? What reading did you get?

FreeBear

Be warned - these things are designed to measure the moisture content of wood and should not be relied on to give accurate readings on plaster. Many things will affect the readings you get, for example the type of paint or wallpaper on the wall, any foil backing in the plasterboard and so on. That said, these meters can be used to monitor a wall to see if it is drying out or if there is a condensation problem but shouldn't be relied on to give accurate readings.

Taking readings on my wall (a lime plaster with some 90 years of assorted paint/wallpaper), I'm getting readings between 17% and 43%. But then I did have a water leak from a pipe upstairs recently.

Just measured a clean, fresh offcut of plasterboard - Reading 19% with a four prong meter.

SteelChair

Freebear, thanks
I used the Brennenstuhl moisture meter from Amazon

brightontraveller

If you like looking at things that generate random numbers there fine as said designed for moisture in timber( and for those rogue damp experts ) even the better one £100-£200 give such varying readings you’d be better of with a pine cone….

DRP

From my damp report:

Protimeter conductivity meter

This meter measures the conductivity of the base material it is being placed against and is a useful non-destructive tool providing helpful information when used correctly for assessing possible underlying damp and moisture content of timber. When used to record conductivity of masonry and cement-based materials the readings received are not measuring quantitative moisture levels, the meter is measuring the electrical resistance of the underlying material it’s being placed against, producing a theoretical measurement which is referred to as wood moisture equivalent or WME %.

When used on the timber the readings recorded are moisture content relative.

Care must be taken interpreting the readings when using these types of meters, contaminants within plasterwork can be electrically conductive. The readings obtained using these meters cannot be relied upon on their own to diagnose rising and penetrating damp. Conductivity meters are a useful tool helpful in producing potential moisture profiles in order to measure possible underlying damp when used correctly.

Conductivity meter readings taken from plaster and masonry of up to around 18% would generally be considered as dry and within acceptable levels in a property of this type provided there is no impact or consequence as a result of the presence of moisture.
Moisture sensitive materials will hold more free water than hard dense materials such as concrete and cement-based products, natural stone, clay brick and lime / ashlar based mortar as used in the construction of this property can absorb a great deal of moisture over time and therefore I would expect higher readings in materials of this type, particularly from external walls which have been exposed to weathering.

The relative moisture contents of skirting boards and lower door frames should be below 22% as this is the level at which decay can occur, ideally relative moisture content of timber work should be between 12-14%.

Where the potential for condensation is considered to be a significant issue a hygrometer may be used to measure relative humidity (RH), air and surface temperature gauges will be used to determine dew point.

Advice and information will be provided in order to manage and control atmospheric moisture reducing the risk of condensation.
I record the levels of WME to the walls, relative moisture content of joinery i.e. skirting boards and lower door frames, humidity, air and surface temperatures prevailing within the property at the time of the inspection, one must appreciate that the humidity air and surface temperature readings vary during normal domestic activities and particularly at night, and could be significantly affected if the property has been vacant for a period of time.

The information recorded during my inspection combined with my overall opinion of the conditions within the property is recorded. I do not rely on instruments alone to assess potential or actual damp conditions within the property my training and many years of experience are all used to provide the client with as comprehensive a report as possible based on the limitations of the inspection (non-destructive) and the accessibility of walls and structural timbers.

brightontraveller

DRP wrote: »

From my damp report:

Unfortunately far too many rely on an instrument designed and calibrated
for one thing on something else? Although I often use a spanner as a hammer ….
A good basic starter is google BRE Digest 245

Link to extracts PDF format
http://www.southend.gov.uk/download/downloads/id/453/damp_and_condensation_presentation.pdf