Tiling onto Underfloor Heating with a Damp Screed - TilersForums.com

[dmtiling]

I'm having a problem, with every floor I'm trying to lay at present (due to our unsavoury weather). The tile assosiation recommend a maximum moisture content of 0.5% in floor screed to tile on. I've just shelled out £350.00 on a professional moisture meter to give me something accurate to go by. Trouble is this is still measuring 4 - 4.5% moisture on perfectly dry screed floors in my centrally heated house. The same as a three week old 4" screed I need to tile on a new build/as yet unheated house :mad2:. I've gone back to the old test method of laying a piece of polythene down (same as your tile) and checking for condensation. Wait until there is none. You will need a heater and dehumidifier to assist in drying. It is very unlikely you have any leaks in the u/floor heating, these are normally laid continuous ie no joints.

 

[diamondtiling]

Re: Tiling onto underfloor heating screed - wet !

Where is ALAN when you need him............:lol:

 

[Dan]

I'm having the same problem Laurie, with every floor I'm trying to lay at present (due to our unsavoury weather). The tile assosiation recommend a maximum moisture content of 0.5% in floor screed to tile on. I've just shelled out £350.00 on a professional moisture meter to give me something accurate to go by. Trouble is this is still measuring 4 - 4.5% moisture on perfectly dry screed floors in my centrally heated house. The same as a three week old 4" screed I need to tile on a new build/as yet unheated house :mad2:. I've gone back to the old test method of laying a piece of polythene down (same as your tile) and checking for condensation. Wait until there is none. You will need a heater and dehumidifier to assist in drying. It is very unlikely you have any leaks in the u/floor heating, these are normally laid continuous ie no joints.

I've moved this to a thread of it's own from the following thread: http://www.tilersforums.com/tile-ad...iling-onto-underfloor-heating-screed-wet.html

 

[DHTiling]

You can force dry the floor with the UFH

Heated cement screeds are not as strong as say an anhydrite screed with in-screed heating, so i personally would recommend the membrane anyway... curling can cause tiles to de-bond..

 

[dmtiling]

I've moved this to a thread of it's own from the following thread: http://www.tilersforums.com/tile-ad...iling-onto-underfloor-heating-screed-wet.html

Why???

 

[Sutwam]

You can force dry the floor with the UFH

Heated cement screeds are not as strong as say an anhydrite screed with in-screed heating, so i personally would recommend the membrane anyway... curling can cause tiles to de-bond..

I agree with Dave, screed curl is an important point. If the screed dries out too quickly the ends can curl up, due to the moisture being driven off the top layer of the concrete it makes the screed take on a slight concave property.

A membrane will not help with screed curl, but using a vapour equalisation membrane such as Detra or CI or equivalent will allow the screed to dry out slowly and the risk of curl would be dramatically reduced.

If you speak to the membrane manufacturers they would say their membrane could be used when you can walk on the screed.

 

[Dan]

Why???

Because the old thread was posted 2 years ago and I guess the guy has his floor done now. I thought as you had the same problem you might want to hear some views from the tilers perhaps?

 

[dmtiling]

mmm, thanks but I dont have a problem with cure's I have been tiling floors for twenty years. I have a problem with £350.00 moisture content measuring devices. My advice would be dont waste your money. My original post was edited and transfered to here, god knows why (thats mods for ya!):smilewinkgrin:

 

[doug boardley]

mmm, thanks but I dont have a problem with cure's I have been tiling floors for twenty years. I have a problem with £350.00 moisture content measuring devices. My advice would be dont waste your money. My original post was edited and transfered to here, god knows why (thats mods for ya!):smilewinkgrin:

if you look who moved it you'll see it was adminrrr: trying to get some fresh replies for you

 

[Gazzer]

If you have a problem with your Damp tester then talk to the manufacturer.

Ajax, our resident Concrete/Screed Guru (god bless him) has covered this subject before and stated (IIRC) that a hair hygrometer was the best method.