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Commercial Flooring News

Knowing How To Use This Instrument Is Key

John Roberts tests the latest Tramex CMexpert 11

I RATE the new Tramex CMexpert11 as an invaluable piece of equipment for checking moisture levels in solid screeds.

It also has spikes for checking wood floors. You can also use it in conjunction with the latest Tramex iprobe, part of the kit to employ it as a hygrometer.

Like the MRH111 which I reviewed in CFJ last year, this new kit comes in a protective carrying case, which will protect it during travel. It looks very professional, an important factor when carrying out checks in

clients premises.

The kit I tested consisted of the meter, spikes, hammer spikes, three iprobes, laser thermometer and calibration check salts tank for iprobes, plus a calibration plate for the meter. It’s non-destructive and works on electrical impedance through the electrodes under the meter. This is achieved by pressing down the meter onto the surface of the floor, and depressing the pins.

There are six buttons, including: On/off, scale, up/down, hold, and backlight. The up and down buttons are only for changing the language. Once set you won’t need to use this button again. To switch on just press the on/off button, which can be used to switch the instrument off before the 10 minutes auto cut- off function, saving battery life. The scale button shifts between different measurements such as concrete, CM Equivalent and pin probe. When connecting the iprobe, the meter automatically changes to this mode. The backlight button is useful in dimly lit conditions. The hold function, I found particular useful when photographing the reading or when lifting the instrument to show a client the reading and for taking readings under a unit or where you cannot see

the screen.

Just press the meter onto the surface even at arm’s length; then press the hold button. The concrete scale is displayed as 0 to 6.9% with 6.9 being very wet. I checked these scales against hygrometers and found readings at or below 3.5% were all below 75% RH. I also found that 4% equated to less than 75% RH on the hygrometer. Conversely readings above 4% equated to over 75% on the hygrometer.

In essence the benchmark is < 3.5%, but please take care as British Standards state moisture reading should be checked using hygrometry. Don’t panic! This kit can conduct tests to British Standards. The meter in non-destructive mode will give you a good indication of the moisture levels and tell you where to set your boxes or sleeves to take relative humidity readings and how a screed is drying. I will explain the instrument’s hygrometry (iprobe, boxes and sleeves) in a follow-up article in CFJ next month. There are a few things to consider when using this equipment. (Anything you don’t know how to use properly is almost worthless!): 1 . Always conduct tests on clean sur faces, without any contamination such as old adhesive etc. That could be conductive and give false information. 2 . If under floor heating is present or the area is being force dried with de-humidifiers, make sure these are turned off for at least two to four days before taking a reading. 3 . If you get dr y and wet readings within a few centimeters you are probably recording the water in the pipes. I have used this meter on top of floorcoverings which give relative readings. Relative readings indicate areas where moisture levels are higher, and show that those areas need fur ther investigation. The instrument can be used during an initial survey for quoting purposes, and also show that there may be a problem which you can tell the customer about. Attaching the spikes and setting it to pin mode allows you to check the moisture in wood subfloors. The new small spike attachment is much stronger than the previous one and allows you to knock it into the wood. This gives more accurate readings, as surface moisture is generally lower than at depth. I found this attachment much more robust than earlier types. The hammer spike attachment are very useful. It allowed me to check the variation of moisture at different levels within the wood. Don’t just take a reading into the surface as this may show wet, but at depth it may be dry. If this is what you find, ask if the floor has been wet mopped before your checks. Next month I will give my full summary of the equipment along with the continuation of this article, covering hygrometry. This instrument will be a better friend if you understand fully how to use it. TAOFS offers training in moisture sur veying with this equipment, as well as those of other manufacturers. This training is offered either on a one to one or in group sessions at your premises if required, or at a venue to suit. John Roberts founder TAOFS (The Academy of Flooring Skills) and a prominent consultant in flooring. TAOFS offers training in all types of floorcoverings. E: E: T: 07831 584334 T: 0116 260 8873 This article has been reproduced from the Contract Flooring Journal website. You can find them at