Moisture Meter - Test Floor Screed Moisture Before Tiling

[Gazzer]

hi i have a £35 one ,not sure wot make ,but all i can say is that we had a guy turn up and do a test for us useing one that cost £2500 and it give the same reading my one did ,lol

On what substrate though ?

 

[TT Tiling]

On what substrate though ?[/QUOTE
concrete floor

 

[Thespanishtiler]

only interested in ajax123's opinion thanks, sick of all the conflicting opinions on gyp floors.

I have a meter

 

[Ajax123]

I personally use two methods predominantly. The first is the tramex moisture encounter meter which works on both concrete and gypsum screed. About £500 worth so not something i would expect most tilers to have. The problem with this on gyp floors is that it can be misleading so you need o have a bit of experiencewith the floors so you can interpret the results. For this reason I always back up a result with an analogue surface hair hygrometer which is freshly calibrated after each use. I trust this method 100%. If the Tramex says its wet then I dont bother with the hygrometer as it is pointless. You can use digital hygrometers which ou can buy for about £80 but these work differently an can be prone to innaccuracy when outside the range about 70 to 85% so if ou get a reading of above 85% you can say its not dry but you can't accurately say by how much. The accurate range is fine though cos it spans the readings we want I.e. 75% and below for cement addy and 85% and below for gypsum addy.

Occasionally I will break out a sample or laboratory analysis and very occasionally use the polythene bag test as an indicator

 

[Dan]

Bumping this one. It might be handy.

 

[Ajax123]

Hi dan. Actually the advice may change soon as a result of some quite extensive independent research on the most accurate moisture test methods along with drying time advice. I will keep you posted .... Excuse the pun.

 

[Dan]

Hi dan. Actually the advice may change soon as a result of some quite extensive independent research on the most accurate moisture test methods along with drying time advice. I will keep you posted .... Excuse the pun.

I LOVE that pun and use it far too much myself.
If you'd like to edit your post, let me know, and I'll change the edit permissions for a day or so when you're ready and you can edit what you've written.

 

[Gazzer]

Dont keep us in suspense !

 

[Ajax123]

I'm waiting for the final report from the independent test house. It's being prepared as we speak. Hopeful to have it along with its conclusions and subsequent advice by end of this month.

 

[Dan]

Looking forward to this.

 

[CJ]

any updates to this?

what are the ideal readings on substrates with say, a Tramex meter?

 

[Ajax123]

Hmm... totally forgot about this. Yes the update was sadly that comparative results using tramex vs hygrometer vs CM method was inconclusive in the results were eratic. However we are set to repeat the work with a new version of the tramex which looks more promising...

 

[CJ]

Is that the Tramex CME5???

What are the ideal meter readings for screeds?

 

[onyrego21]

I am wondering if somebody tried buying cheap humidity probes from China and comparing the results with a professional tool. I would like to measure the moisture content of my anhydride screed but buying 1250Eur Tramex kit is quite expensive (CMEX5 + a cable + probes).

When you take a look at the expensive "professional" tools, they seem very similar to what you get from china.

I am thinking of drilling a hole and putting the cheap probe inside + butyl tape isolation on the top to equalise the humidity.

Even the Hygrohood can be DIY for 30Eur - a plastic box 5eur, a butyl tape 5eur and a wireless humidity sensor 20Eur.

If you take a closer look at the Hygrohood, the humidity meter looks like Tramex used the cheapest they could find.

 

[Ajax123]

Is that the Tramex CME5???

What are the ideal meter readings for screeds?

I cant remember if it's the 5... I think so but I can check tomorrow

 

[Ajax123]

I am wondering if somebody tried buying cheap humidity probes from China and comparing the results with a professional tool. I would like to measure the moisture content of my anhydride screed but buying 1250Eur Tramex kit is quite expensive (CMEX5 + a cable + probes).

When you take a look at the expensive "professional" tools, they seem very similar to what you get from china.

I am thinking of drilling a hole and putting the cheap probe inside + butyl tape isolation on the top to equalise the humidity.

Even the Hygrohood can be DIY for 30Eur - a plastic box 5eur, a butyl tape 5eur and a wireless humidity sensor 20Eur.

If you take a closer look at the Hygrohood, the humidity meter looks like Tramex used the cheapest they could find.

A simple floor hygrometer is about £100... The hygrometer is a European standard recognised test but it can be tricky as its affected by temperature and humidity changes. I've used them dozens if not hundreds if times. You cant always take the readings for granted. You do not need a wireless sensor. It simply stick to the floor using water free tape and you take readings after about 4 hours (if it's over about 80% you might as well take it up as it's still wet) if after 4 hours its below 80% read it after a full 24 hours and then again after 48 hours. If both readings are below 75% its dry. If both are above 80 % it's not dry, if both readings are between 75 and 80 you can do some interpretation with experience but that takes a while to work out as you have to take account of lots of variables finally If one reading is below 75 and one above it usually means its almost dry and responding to environmental conditions. The underfloor heating must be off for 48 hours prior to testing. My preference is tge carbide bomb but that's expensive and not really a DIY job. Bear in mind that ALL the same issues and uncertainties exist with any type of screed or concrete.

If you use a gypsum based tile adhesive on anhydrite screed you reduce risk of failure very significantly as you remove any chemical incompatibility problems.