Advice on tiling onto "overlay" underfloor heating - TilersForums.com

[Uheat - Jake]

Very interesting thread...

The Hetta system is a popular one which many suppliers of UFH sell, however any type of EPS or XPS Polystyrene boards need a overboard before any form of tile can be applied to it. These systems are really suited for a Engineered Wood or Laminate. You can use a screed board over the top of it which is then fixed to the sub base however you have to be very careful of the pipes and where you're placing the screws.
These very reasons are why there's a new type of product on the market which is the Gypsum Retrofit panels which are a solid gypsum board which can accept a tile directly laid on top. The Gypsum boards have certainly become more popular recently due to not needing any extra materials. We supply a 18mm Version of this panel with pre-grooved pipe channels and end returns built in, suitable for a 12mm PERT Pipe. These boards can be primmed on the face and base before any adhesive or leveller is applied.
With our boards we state that the unused pipe channels need to be filled with compound before either a decoupling or tile is laid, this removes any voids that could be under the floor. I've attached a few photos from customers installations. If anyone needs any help on a system or installation, give me a call or send me a PM as we're happy to help everytime!

 

[Old Mod]

there's a new type of product on the market which is the Gypsum Retrofit panels which are a solid gypsum board which can accept a tile directly laid on top.

The polypipe system which has been around a while uses gypsum boards, and after a few years of publishing different installation techniques, they’ve finally produced a method statement in lines with what we want as fixers.
Which is to have a latex layer over the pipes of approx 5mm, then preference is a
decoupler/anti fracture mat, then tile.
The mat not being essential for porcelain but definitely with natural products and thin tile, but always preferred.
Although there are Tiler’s that will fix straight to the boards, there’s certainly another school of thought that feels that this is not the most effective method.
Also a lot of people miss the fact that they are gypsum and not cement!!
Therefore, priming correctly is essential, whether it be before latex or adhesive.
They are not a match made in heaven.

 

[Uheat - Jake]

The polypipe system which has been around a while uses gypsum boards, and after a few years of publishing different installation techniques, they’ve finally produced a method statement in lines with what we want as fixers.
Which is to have a latex layer over the pipes of approx 5mm, then preference is a
decoupler/anti fracture mat, then tile.
The mat not being essential for porcelain but definitely with natural products and thin tile, but always preferred.
Although there are Tiler’s that will fix straight to the boards, there’s certainly another school of thought that feels that this is not the most effective method.
Also a lot of people miss the fact that they are gypsum and not cement!!
Therefore, priming correctly is essential, whether it be before latex or adhesive.
They are not a match made in heaven.

A Flexible SLC is perfectly fine to go over our panels as well before a decoupler is applied and is also the easier method as it'll fill the unused pipe channels as well.

 

[One Day]

....
Also a lot of people miss the fact that they are gypsum and not cement!!
Therefore, priming correctly is essential, whether it be before latex or adhesive.

THIS!!! (x100)

 

[Jonner]

Thanks again everyone. Your comments are making me feel more and more confident about the gypsum board based UFH that we are now looking at from Nu Heat called Lo Pro 10.
I will ensure that the gypsum boards are sealed/primed with SBR prior to install followed by de-coupler.

Marc - as yet no decisions re the tiles! Although it is an old cottage we are currently not thinking natural stone due to the need for sealing and maintenance. We are after something hard wearing, with a natural stone type texture/pattern (not polished smooth) in light tan/beige colour, oh and not expensive as we have about 60m2 to tile. So any recommendations on tiles and then adhesive would be great.

 

[Jonner]

Hi All
As mentioned previously thank so much for all the help provided here. We are going ahead with the Nu Heat low pro 10 approach. Once down we are going to be laying Limestone tiles of 22mm thickness.
Any further comments/advise is most welcome.
Best Wishes
Jon

 

[Qwerty]

My only (and fairly significant) comment is that the Nuheat low pro 10 system appears to be only suitable for dry lay flooring, not tiles.

 

[Flintstone]

With regards to your tile, I have a job in the pipeline with some 600x400 matt porcelain, which are a stone look tile and they are very realistic. I will try and get some photos if you like this week.

 

[Jonner]

Thank ACT that would be great.

 

[Jonner]

Hi Plan Tec
having looked at all of the Low Pro 10 data sheets and posted them on here last week i am surprised that you dont think it suitable for tiling. It says on the data sheet that tiles are fine, and having spoken to them direct they said tiling was "the best option". If you have had another experience then please let me know. Many thanks Jon