opus pattern problem

[nosamekul]

got a job coming up , a four size opus pattern style porcelain floor i have done several of these over the years but have always laid them level to avoid any lippage etc due to the differing grout joints direction etc , however the screed on this job is laid to a massive fall due to levels of opposing doors being out in house i was just wonderiong do these patterns work laid on a drastic fall over 40m2 with kichen islands etc to tile around . and one other point i would like some help with is does anyone know the minimum thickness of screed that should go over cellotex and piped u.f.h as it looks on the lowest point on this job its only an inch , inch and a half max (very worrying ) any help would be appreciated not sure weather to walk away or not

 

[charlie1]

Prep it or walk away! You worry is understandable, its the same with any floor or wall though regardless of pattern, imagine your flat bed sheets, it you pull them up in the middle what happens? The sides come in!! Same thing will happen to grout joints depending on several factors. ... Don't laugh at my example lol, all i could think of

 

[nosamekul]

it is a fall from one end of the room to the other which worrys me but the thickness of the screed is a big concern aswell having seen how much the cellotex sheets move and flex it cant be structually very good surely ?

 

[White Room]

The screed should be 70mm....

 

[Colour Republic]

The screed should be 70mm....

i don't do these myself but I was reading somewhere just the other day that 50mm is the optimum and 75mm is starting to push it. To be honest I always thought it was 75mm myself so was surprised to read it. Just need to remember what system they were talking about now

 

[Diamond Pool Finishers]

i though a floating floor was 65mm traditional S&C, and modified was 35mm, should look-it -up or check with ajax !!.....

 

[Aston]

my take on a floating screed is below [FONT=&quot] [/FONT]
[FONT=&quot] [/FONT][FONT=&quot]Minimum depth 65mm – maximum depth 90mm[/FONT][FONT=&quot] (domesticsituations) [/FONT][FONT=&quot]houses, flats etc[/FONT]
[FONT=&quot] Minimum depth 75mm – maximum depth 100mm (commercial situations) [/FONT][FONT=&quot]offices, factories etc[/FONT]

 

[nosamekul]

thanks for replys on screed thickness any thoughts on laying opus pattern on a fall ?

 

[AliGage]

thanks for replys on screed thickness any thoughts on laying opus pattern on a fall ?

Depends on the fall(s). If it falls in only one direction and is relatively flat. Are you intending on levelling/eliminating the floor with the tiles?

 

[swanman]

Walk away

 

[DHTiling]

As long as the floor is flat it will be fine , it does not have to bubble level if the floor is out that much , just get it flat to eliminate lippage as you say. when cross bonding.

 

[nosamekul]

cant level floor at all as there is no height to play with hence shallow screed as some one messed up level/heights i think not even enough for an uncoupoling membrane of any sort literally mms to play with

 

[Ajax123]

Minimum depths for sand cement screed floating on any tye of insulation in domestic settings is 65mm. Minimum 75mm for commercial. It should also be reinforced with either d49 steel mesh or polypropylene fibres. There is no recommendation for maximum depth but this will be governed by available height, cost and drying time. As it is very difficult to get sand cement under the pipes with UFH the minimum depth should be measured from the of of the pipe so most heated sand cement screeds will be 75mm to 80mm.

If it is a Gypsol screed you only need 25mm cover to the top of the pipes so the screed will be much thinner. and a Gyvlon screed will need at least 30mm cover to pipes. Typically anhydrite will be 45 to 55mm deep with UFH. No reinforcement is needed for anhydrite screeds either.

 

[nosamekul]

So in all likelyhood a s/c screed will crack up but a gypsol screed will be ok with said thickness any differantway i should approach tiling a gypsol screed appose to a stabndard s/c thanks

 

[Ajax123]

So in all likelyhood a s/c screed will crack up but a gypsol screed will be ok with said thickness any differantway i should approach tiling a gypsol screed appose to a stabndard s/c thanks

Gypsol is an anhydrite based screed so you need to deal with it as such. Sand it and vac it. Check its dry. Make sure heating is properly comissioned and run then tile using ideally a gypsum based adhesive such as gypfix from nicobond or alternatively a gypsum compatible one like h40 ideal from kerakoll