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Accurate damp diagnosis using our gravimetric lab

12 December 2012

Accurate Damp diagnosis.

Is a wall really damp or is it just the plaster that’s wrong?

Electronic moisture or damp meters are very useful and we use them all the time. However, they do have their limitations, especially when salt contamination of plaster is involved and precise damp diagnosis is essential.

Damp proofing is as much about specialist plastering as it is about chemical damp course installation. The two go together and rely on each other to achieve a dry wall.

So, where electronic moisture readings are high, how do you rule out or confirm the real damp problem accurately? Our Gravimetric testing lab and salts analysis equipment addresses this in a proven accurate way.

Gravimetric testing involves measuring the moisture content using gravity/weight of samples in dry and wet conditions.

This is how we do it:

Samples of the plaster and/or masonry are taken at various levels from the suspect area
They are sealed and then carefully weighed
They are then subjected to a constant 75% Relative Humidity for about 48 hours.
They are weighed again and the gain or loss noted
They are then placed in a lab oven, to dry fully overnight and are weighed again.

We can then compare the dry weight – wet weight and air-dry weight and calculate the total moisture content and hygroscopic moisture content.

In other words we now know not only how much water is in the wall, but why it is there and how it is distributed.

Is it rising damp? Penetrating damp? Salt damp? Condensation? Damp proofing can be a hopeless exercise without accurate damp diagnosis.

The samples are preserved by the process, so they can also be subjected to further analysis for salts such as Chlorides and Nitrates, which could imply a soil borne source.

Our gravimetric moisture lab is part of our in-depth damp diagnosis consultancy service; an investment in bringing state of the art damp diagnosis to Yorkshire.

Please contact us for further information or advice.

damp diagnosis using gravimetric testing to BRE 245