Moisture meters

[Jeremy Nicoll - news posts]

I'be been looking on ebay, amazon etc at moisture/damp meters. leaving aside the sort of thing a surveyor might use, these seem to vary in price from about £12 to £40 - or even £70 is one were foolish enough to pay the rrp of the Stanley one.

Most seem to be a fairly standard-shape box with a couple of prongs, and a LCD display, though there's a few - mainly cheaper than the rest - with an analog display. Some have the prongs in a probe at the end of a stretch cable.

It looks to me as if the type with the cabled probe would be good for testing in corners at arm's length.

But are these things accurate?

Does anyone recommend any particular model?

[<me9]

Unless you need it for sustained use, a multimeter and two drawing pins is about as accurate as a ready made one. Google is your friend.

That is how I monitored my floorboards and joists after a recent (sustained) flood from dishwasher.

[Ret.]

I bought an inexpensive model for use in my caravan. It was the type with the two prongs on the end of a length of cable and, yes, IMO they are more useful than the type with the prongs built into the end of the device. You can get the cabled prongs into awkward corners that you could not get the whole device into.

It worked very effectively - it had an analogue dial with green, amber and red sections. If the needle swung across into the red then you knew you had damp.

It was a Rapitest - like this one here:

[Nick Odell]

I agree. Sans the drawing pins in my case because the pointy ends of the multimeter probes worked fine. Set to the resistance range, a few test probes in known dry and known damp materials for callibration purposes and away you go.

Nick

[Paul - xxx]

identical, works well as a comparator, which is all you're after .. ;)

[NT]

Multimeters are available from =A32:08 frm rapidonline, and are far more use than 'damp meters.' DMs are accurate with wood, but not at all with masonry.

NT

[NT]

Theyre also fairly irrelevant with masonry. Either you see signs of a damp problem, or you dont. If you dont, there isnt one.

NT

[Jeremy Nicoll - news posts]

Thanks to everyone for their comments.

[Andrew Gabriel]

Mine's a no-name ST-125 from CPC when it was half price (£10). Works well, and has a scale for timber and a scale for masonry. Probes are attached and it doesn't have a hold button, which can be a problem when the only way to get it in to the material leaves the LCD display not visible (and no backlight if it's dark). It has battery test and calibration test facility.

For timber, the most important range to read accurately is between

10% and 20%, although this one goes from 6% to 44%.

It seems to be remarkably consistent, and readings are exactly what I would expect, so I suspect it's quite accurate.