Just pricing up a job on some spec sheets. The screed I will be laying over is 75mm thick cement sand quick drying isocrete standard K screed Anyone know what it is and will it need a surface dpm on top. I'm thinking yeah as no screed that thick can dry that quick, can it?
Thats standard Daz if memory serves correct the isocrete is a chemical adative thats add to the mix to speed up drying times. Due to this adative which works much the same way as Ardex 55 you will always pick up the moisture content using the MMS best to use the good ol fashioned trusty Hygrometre. The reason the MMS will still register is because the chemical adative forces the moisture to crystalise in the screed stopping it from escaping, you can go back in 10 years time and still get the same readings. The best thing to do is put it in the quote as a provisional sum subject to sub-floor survey. That way atleast you're being upfront and no ones gonna get any shocks later on its a figure that could be omited should it not be required at a latter date.
My misstake its the K which is the adative and there are many types but they all do the same dry quick. Just type Isocrete into google mate loads of info there on it.
It the spec it mentions the floors have to be below 75% RH or a SDPM has to be used so at least they know. In fact lots of British standards On there. I'll see if I can copy and paste in later
Plus it will and is the main contractors reasponsability to ensure the screed gets below the suggested level of 75% RH and produce an acurate drying certificate, I have yet to recieve one of those.
