Floor prep dilemma

[kingofthehill]

Hi all

Essentially trying to get a feel for how good floor preparation needs to be. I'll try to describe the scenario below.....

Small hallway in terraced house. From front entrance door the area is approx. 1m wide. This is full width of floor along its length. The floor is 2.6m long at which point it meets bottom of stairs (reasonably typical terraced house passageway). Concrete.

I have removed existing tiles and am now doing my best to prep for the tiling.

Problem:
Floor is not completely flat.

Usually easy to remedy with self levelling compound which I have done on other projects with no issues. However, this floor is neither flat nor level. I have ruled out levelling with levelling compound because the whole floor runs downhill towards the front door. The amount of fall is 60mm over this distance. If pouring levelling compound, the resultant floor will be higher than the underside of the front door. Obviously no good as it will prevent the door from opening!

This aside, the floor also runs out of level from left to right as a result of remedial work in the past to lay a new mains water pipe. A 0.3m strip was dug up along the right hand wall. When this was filled in it wasn't done so that it was coplanar with the existing floor so slopes off towards the side wall. The fall at the extreme edge is about 15mm. To make matters worse, the floor also slopes off towards the stairs in a similar fashion.

I didn't want to use a sand and cement mix to try to level this out because I was conscious of this thin layer breaking up with movement and undermining the tile adhesive. I have had the bright idea of using levelling compound mixed up with less water to make a thicker mixture and used this best I can to try and build out the lowest areas. Let's just say that it has worked to some extent but not so much in the worst places.

Laying porcelain tiles 600mm x 300mm. I have bought a 10mm square notch trowel as that's all that was available locally (probably would have opted for a 12mm one otherwise. I intend to use the wedge type tile levelers.

I will try to post a picture of the floor, but judging by my description above, does it sound like I am setting myself up for a poor installation with edge lippage or is it possible to get away with this by lifting and relaying problematic tiles as and when necessary during installation?

So a s I said to begin with.... How good does the floor prep need to be? i.e. Like a sheet of glass? Or is it possible that my efforts have been good enough to proceed?

 

[kingofthehill]

 

[tell80]

Your latest SLC looks to have been applied proud & semi-dry, previous applications dont look much better.
SLC should always, even if mixed with bulk sand, be mixed & applied in a workable, featherable condition.
The concrete shows significant cracks, & is "neither flat nor level".
Its dropping 60mm over a short distance with the centre sloping 15mm to each side.
Yet given the above you have bought large 600mm x 300mm tiles - perhaps a bad choice?

If its a thin concrete layer then maybe demolish the floor and pour a new surface, make it best flat and level as you can get it?

Or vacuum what you've got and heavy butter both the floor and the tile - buttering & setting it tile by tile as you go. Constantly use your short level & long level.
Your wedge type levellers will help, but in the longer run the tiles will be open to possible cracking or grout pop.

The 60mm drop suggests a structural fault beyond a flooring issue?

 

[kingofthehill]

Thanks for taking the time to reply. Yes I was unable to apply SLC in a flowable state for the reasons stated above. It is feathered actually, there are no fat edges on it. However, it is, as you can see, a bit of a patchwork. This is as good as it is going to get under the circumstances, I have done my best to create a flat surface and was trying to get a feel for the level of increased difficulty this will cause when fitting. I think you have probably answered that question. Sounds like it will be doable but difficult. I'm ok with that.

Regards tile size, in my view 600x300 is small lol. Have you tried to buy floor tiles these days? It is what it is.

Demolishing and repouring the floor is not an option without either raising the front doorstep to the required level and fitting a new door or lowering the floor level significantly at the interior door threshold. Neither is realistically an option. Hence why I am trying to make do.

Your comments regarding the double buttering etc. are appreciated and will no doubt help when going through the motions of installation.

If anyone has any other tips for tiling under these circumstances...... gratefully received.

Regards the 60mm fall. No structural problems, just a very old terraced property. Not a plumb or level wall, floor, ceiling, door frame, roof etc. in the house in it's entirety. It just is how it is. Plenty of properties like this or worse in this area.