200sqm floor, prep discussion

[Doozy]

Got a site meeting next week where the installation of a 200sqm floor will be discussed.

There are a handful of smaller rooms involved on the periphery, but the main area is basically T shaped. The bottom of the T is the entrance hall at around 26sqm, which opens up on the top line of the T as a rectangular room of around 80sqm.

This is a sand and cement screeded floor over water piped UFH.

The builder says no expansion joints are required and the screeder says no decoupling is required either.

I obviously have my own thoughts on the matter, but I wondered what the consensus was on here

 

[Dumbo]

Ask the builder and the screede if they will put it right if it goes wrong if you do it their way . Me I would decouple and expansion joints

 

[Andy Allen]

What tiles are they using....??

 

[Simon Dale]

Decouple, expansion every 8mts i think ? My thoughts on expansion if their not in the substrate already do they work ??

 

[Simon Dale]

Tiled Limestone floor in Virginia Water longest run over 30 mts no expansion joints. Customer didn't want them no probs after 5yr app

 

[Doozy]

Tiles are 900 square Andy

 

[Ajax123]

Cant see what it has got to do with the screeder as to whether decoupling is needed or not.

 

[Alex Reed]

Got very similar sized floor to do in 3 weeks over a flowscreed (anhydrite). 800x800 porcelain. Using anhyfix to tile. Is a decoupler required? And hard or soft expansion joints and where? Am going to see it this week but would imagine there is no expansion joints in the screed. Any information/advice greatly appreciated.

 

[Benn Simmonds]

Got very similar sized floor to do in 3 weeks over a flowscreed (anhydrite). 800x800 porcelain. Using anhyfix to tile. Is a decoupler required? And hard or soft expansion joints and where? Am going to see it this week but would imagine there is no expansion joints in the screed. Any information/advice greatly appreciated.

If your using anhyfix by tile master And you want to decouple. Use anhyfix to lay anti fracture matting. Then use setaflex on matting. Cheaper way of doing it.

 

[Alex Reed]

Thanks. Is a decoupler required? We use them with natural stone but from researching am led to believe with porcelain and a flow screed it isn't necessary.....?

 

[Benn Simmonds]

Thanks. Is a decoupler required? We use them with natural stone but from researching am led to believe with porcelain and a flow screed it isn't necessary.....?

It' not really necessary but it' belt and braces. If you think you should use it then do. It will cost you more if the floor fails.
Personally I would Matt it and tile it.

 

[Dumbo]

If you look at the difference in expansion between porcelain and anhydrate there is a difference. Not sure what it is but their is and over a large area it matters because it adds up . So I would very much decouple

 

[Chris Gibbs]

Thanks. Is a decoupler required? We use them with natural stone but from researching am led to believe with porcelain and a flow screed it isn't necessary.....?

I would use an anti fracture mat. Anhydrite floor isn't prone to big movement but when heating goes on underneath you cant be too careful. it also gives the customer confidence in your methods too knowing you're covering all bases.

 

[Chris Gibbs]

on an Anhydrite floor

 

[Dumbo]

I would use an anti fracture mat. Anhydrite floor isn't prone to big movement but when heating goes on underneath you cant be too careful. it also gives the customer confidence in your methods too knowing you're covering all bases.

I believe from figures quoted by @Ajax123 on a previous thread unless I misunderstood that the porcelain expands more than the anhydrate

 

[Chris Gibbs]

I believe from figures quoted by @Ajax123 on a previous thread unless I misunderstood that the porcelain expands more than the anhydrate

exactly... and these floors can get quite hot if required

 

[Chris Gibbs]

I believe from figures quoted by @Ajax123 on a previous thread unless I misunderstood that the porcelain expands more than the anhydrate

exactly... and these floors can get quite hot if required

 

[GoneGuy]

I would go belt and braces and use a anti fracture mat.

 

[Flintstone]

I wouldn’t and I don’t decouple on anhydrite with porcelain and ufh.

A new sand and cement screed with ufh - yes

 

[Alex Reed]

Thats great. Thanks guys. Will see the builder/owner this week and suggest all possibilities to him. We done a 150m2 porcelain one before Xmas with Ditra but that was on sand/cement screed. Have been using BAL rapid Matt on the last few floors (40 m2 plus) onto nu heat gypsum boards with wet ufh screwed down to glued and screwed caberdeck stuck with mapei S2 and then tiled with Weber s1. Floors seemed really solid. Time will tell....... Thanks for your knowledge guys

 

[Doozy]

Cant see what it has got to do with the screeder as to whether decoupling is needed or not.

Therein being my point. He just happens to have been there before me imparting his wisdom on the customer.

 

[Doozy]

So been this morning. After all that, it turns out it's Gyvlon not sand and cement

 

[Dumbo]

Still expansion joints and decouple for me

 

[wh tiling]

Got a site meeting next week where the installation of a 200sqm floor will be discussed.

There are a handful of smaller rooms involved on the periphery, but the main area is basically T shaped. The bottom of the T is the entrance hall at around 26sqm, which opens up on the top line of the T as a rectangular room of around 80sqm.

This is a sand and cement screeded floor over water piped UFH.

The builder says no expansion joints are required and the screeder says no decoupling is required either.

I obviously have my own thoughts on the matter, but I wondered what the consensus was on here

how long has the screed been down
+

 

[Chalker]

Has the ufh been commissioned yet?

 

[Doozy]

Screed is only just in, but the tiling is circa 6/8 weeks off and yes, the heating will be commissioned

 

[Doozy]

Actually, scrub that, tiling will be about 10 weeks

 

[Tommythetiler80]

on an Anhydrite floor

View attachment 97231 View attachment 97232

Are those tiles 1200x600 chamboard gres Chris?

 

[Chris Gibbs]

Are those tiles 1200x600 chamboard gres Chris?

They were a florim porcelain, bang on size and cut a dream too 1200 x 600 and about 150m of them.

 

[Lee@emctiles]

ok, so similar situation i found myself involved in.

270m2 ground floor house. anhydrite screed. few cracks appearing now in screed as UFH has been turned on (even thou the laitance hasn't been took off yet, thats another story)

tiles being used are 22.5x85 wood planks.

having just costed the expansion strips and matting, customer isnt happy with extra costs......

so what to do? No decoupler and use expansion strips? Or decouple and no expansion strips?