Watec2E

[jddevel]

Sometime ago having researched laying tiles on to "green screeds" not only using the forum but talking to Mapei Technical and other adhesive technical depts. I decided wanting a "belt and braces" result against cracking etc ( expensive property) decided to try Watec2E and Mapie Rapid with a latex additive.The result fantastic. As a developer my personal involvement in fixing tiles is somewhat limited to the odd wall and floor area. This floor was not far short of 100sq.mtrs on a green screed which whilst it had been down a little while had been subject to other "wet" trades". It was just swept and Watec2E laid as a floating course before the "professionals" got to work tiling. The wet underfloor heating was put on and temperature raised over about a week. Prior to this and inspite of asking the pump screed applicators shouldn`t we have some expansion joints ( they said not -should be O.K.) one area through a 1500mm opening cracked ( about 2/3mm depending on floor temperature) across the opening. The tiles have been down now about four weeks and whilst I can see the crack moving ( tiles end in doorway and oak floor to continue- but not yet laid-it will also float) THERE HAS BEEN NO CRACKING OF THE 8MM PORCELAIN TILES inspite of foot traffic. I`m very impressed so were the tilers both with the time taken in preparation -virtually nil and the ease of laying adhesive and tiles. So whilst expensive where peace of mind is important I highly recommend it. Anyone else used it?

[Dave]

I have looked at it before...but as you say it is pricey...

[Ajax123]

Looks very similar to Durabase CI to me.

The pump screed applicators were Technically incorrect in advising you that movement joints were not required all though pumped calcium sulphate screeds can be more tolerant to the lack of joints due to them having greater dimensional stability. However these as with all screeds should be jointed appropriately to allow for movement. All should have joints through door thresholds and between independently controlled heating zones. I assume the lack of such a joint is why your crack appeared. Other joints will largely be dependent on the screed type, configuration and construction method and in heated screeds these joints should be created to extend through the full depth of the screed. Uncoupling is not a suitable method of replacing joints in screeds when they should be there. One of the issues of course is vertical movement (e.g. caused by curling in cement based materials) which cannot be overcome by the use of uncoupling membranes. Although they are a great method for adding stability and speed to a project they are not the be all and end all.

Glad you are happy with the end result though. Good sales pitch for Watec 2e IMO.