Can damp meters be wrong?

Jun 9, 2023
Hi, my damp meter is showing 100% damp in 2 spots on my caravan. Funny thing is, both spots are bone dry with no signs of damp at all. Also, both spots are in direct opposite sides to each other. Where the meter is showing 100%, it starts and finishes at the exact same spot on both sides of caravan . Ive read somewere that these meters pick up metal and wires also. The 2 spots r behind an overhead storage cupboard on a 2008 bailey ranger, any advice would be welcomed
Mar 14, 2005
Hello Wonderbuoy, and welcome to the forum.

Most damp meters use two points which have to be pushed into the material that you want to test. The points al ow the meter to measure the electrical resistance between them. There is a correlation between the electrical resistance of the material its temperature and the level of moisture in the material.

If you contact metal it will show a very low resistance or a very high moisture content.

But another factor when dealing with caravans, is the fact many caravan inner walls are covered with a Vinyl covering which is normally waterproof. You have to make sure the vinyl is dry, otherwise that can cause a false reading, and also the pins of the meter need to penetrate the vinyl coating to get at the wood underneath.

The professional moisture content meters are very expensive, and the user needs to know how to interpret the results in the context of the materials under test.

Low cost consumer meter are unlikely to be calibrated with the same degree of accuracy, so they can only really be trusted to be indicative rather than precisie.


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