Tiling over new screed

[eddieu]

Lo all
My kitchen had one corner of concrete floor some of which had blown
the rest was 1" thick bitumen which ran out of true 2.5" over the kitchen length, so as as result i removed the lot and layed a new floor
4 - 1 sharp sand and cement. its perfectly flat and level although i left
a rough finish as i thought this would help adhesion the room is 16' x 8' approx
and the screed is 2.5" one end and 0.5" at the other. I then went to a tile supply store who told me that as the screed was so new i would have to use a speacial adhesive at £42 a bag, i'm gonna need 4-5 bags approx, seems an expensive measure to me.
my brother inlaw then says forget that lay a thin latex coat and use normal adhesive then a m8 says forget both of those you should not touch it for 4 - 5 weeks or the screed will crumble and the tiles will come up, help my heads spinning, any tiling experts out there who can steer me right, thanx in advance.

 

[Jasonb]

Tile shop was right if you use something like BAL Green Screed Adhesive you can tile the screed 24hrs after laying. The other option would have been to use BAL rapid set cement when you did the screed, again you could have tiled next day.

Other wise leave for approx 3weeks at that depth then use standard adhesive

I would be worried about the strength of a sand cement screed that is only 1/2" thick, there is a high risk of it failing regardless of how you tile it

Jason

 

[eddieu]

Could'nt go any deeper as it had to be level with the living room,
what should i have used instead for the thinner section ?
thanx for reply

 

[Jasonb]

Ideally hacked up some of the concrete below to give 2 1/2" all over.

You could also have used a self leveler that can be laid to a decent depth, some go upto 35mm thick or bulked up a regualr selfleveler with granit dust.

Jason

 

[eddieu]

I've still to lay the last quarter of the floor, you recommend
a self levelling compound rather than screed any idea
where i can purchase the stuff that can be laid at the thickness
you spoke of because ive never seen it
how could i have taken 2.5 inches off the existing concrete without
taking up the whole lot ?

 

[Jasonb]

On the thinner areas you would be better with a selfleveler as it is less likely to fail, look for Ardex K15 or K15B, or one of the Mapei products such as Topcem or their Ultraplan Eco that can be built up in layers 10mm at a time.

Yep you would have needed to rip the lot up.

Jason