Damp meter readings

I stole this from another forum. I have found the same info in the past but cannot remember where.

Here are the industry reference points relating to moisture levels in caravans.

These measurements are ONLY for use with the Protimeter tester, not any of the cheap and cheerful, and very misleading, other makes.

Readings between 0-15% no cause for concern

Readings between 15-20% engineer to make note of readings and recheck at next service.

Readings between 20-24% possible early sign of water ingress, look for tangible evidence or ask for

Recheck.

Readings between 25-30% moisture evident, remedial work necessary, may not require stripdown unless surface damage (staining, pimpling and softness) is apparent. There is a risk of wallboard deterioration due to retained moisture in the structure if re sealed only.

Reading of 31% and above structural damage is occurring, deterioration inevitable, full stripdown of affected area is required

Whilst it seems very simple to get a reading and think you have a problem, it is not and other considerations have to be borne in mind when taking readings, such as ambient temperature, humidity etc.

Husky, our back wall is the coldest spot in the van. In fact if we don't leave a cupboard open in that area it gets condensation and if this isn't checked the damp from the condensation could easily build up. Maybe this points to the different readings?

If I could give a little further info as well. Any readings over 20% if left the timber will rot. When taking the damp readings with the Protometer you must make sure that the two metal prongs penetrate the outer surface of the area that you are testing. That will ensure you are reading the timber below the surface where it is possible you could read moisture as a result of condensation. The only downside us that you will have two very small puncture holes

Here's my take on this: unless you are using a professional (hundreds of pounds) meter, the actual reading is less important than the relative readings.

In this case if one area is significantly higher than everywhere else then it is worth investigating. It may be that the actual levels are say, 10% everywhere except one place that is 18 or 20%. So no problem. Equally it may be that the general reading is actually 15 or 20% and that one area is 30%. - needs looking at.

Probably best to wait for a dry, mild day and recheck. If there is still one area significantly above the rest then investigate.

If you want a free damp check drive to your local dealer, show interest in something much more expensive than you have and ask for a part exchange price. Don't be fobbed off with a "subject to survey" price insist on a fixed figure. The salesman will whip out a pro meter - just make sure you are looking over his shoulder.

Downside to that it the figure you are given will depress you.

i have found the problem , the cover where the sat cable goes through the roof had lifted and water is seeping through , just needs taking off and cleaning up and resealing , and let it dry and recheck in a few months 

Good to hear you've solved it Husky!