Creating Smooth Gradient Where Wall Has Been Removed

[Thomas Moore]

Afternoon all,

Another newbie question here. Got some great advice last time so hoping you might be able to help me out with this one.

We're refurbing a through kitchen / diner. Sometime in the past, a brick wall separated the two rooms. This has been removed and has left a finger-shaped ridge in the floor (approx. 2m x 60cm). The foundation of the old brick wall has been patched up with concrete and the rest of the floor is the residue of bitumen adhesive from 1950s 9x9 vinyl asbestos tiles. The difference in the height of the floor across the width of the concrete 'finger' is about 2-4cm.

I was planning to use SLC on the entire floor and then tile it. However, we've been advised not to, since it will raise the level of the lower section of the floor and create a high step into the room. It's also unnecessary since the two halves of the floor are each reasonably level - just not level with each other! The plan instead is to smooth out the ridge, creating a gentle gradient which can then be tiled.

I've been advised to use a levelling compound and a straight edge to shape a gentle slope ready for tiling. However, I'm stuck trying to find a suitable compound. Presumably I can't use a *self*levelling compound, since it needs to be trowelled on and hold the shape of the slope until set.

Any recommendations on what would work best for this - both in terms of a suitable compound and any tips on technique?

As always, all help and advice is much appreciated, guys.

 

[White Room]

Some slc can be quite rapid nowadays....

 

[Old Mod]

Can u provide a couple of images please. One fairly close up and one which will show how this ridge relates to the room as a whole.
Thanks.

 

[Thomas Moore]

Sure, here are some photos.

 

[Old Mod]

So the left hand side, so to speak is flat and level and the right side is flat and level.
They're just different levels, is that right?
What's the tile u are using?
And which side is the entrance to the room

 

[White Room]

The second picture looks like the floor is rising up from the dip.....

 

[StevieBoy]

The second picture looks like the floor is rising up from the dip.....

Agreed as the left side of the level in pic 4 looks flat to the rubber handle bit, then the floor dips then it looks like it rises back to the same level again.

If so, just tile it, making sure there all flat to the level and build em up.

 

[Old Mod]

Well it says in the third paragraph that both sides are level, just not with each other!

 

[widler]

Ok, it's obvious that the 2 floors are not the same height, it happens when they asphalt the floors either side,you can't get them mm perfect, so you take a wall out and you have two different heights, it also may run up a bit .
you canfeather SLC from the high spot and run it as far as you can, don't worry about the SLC running away, just don't mix it to runny and trowel it flat at the edge .
Depending what tile you are using and which layout, you can run your tiles from either side of the 'dip' to lose it .
or you can knock the new stuff up, cut the high floor back a few foot, re fill it and repeat the steps above for a flatter floor, which is the slower option but will make it flatter

 

[Thomas Moore]

Morning guys. Apologies for the delay in answering the questions. I'm attaching a quick floor plan with the rough area of the ridge highlighted in red.

Yes, 3_fall, you're right: both sides are fairly flat (with a gentle slope) but the left-hand side is slightly higher than the right. There are two entrances to the room, one on the left side and one on the right. You can probably see from the first picture that there used to a be a doorway connecting the two halves of the room before the wall was removed. At this point, of course, the floor levels are the same.

The tiles are 662x235x8mm wood-effect ceramic. The plan is to lay them left to right since there's a window at each end of the room. As such, they would lay across the change in level.

Apologies for the confusion over the levels and whether there's a dip in the floor. There isn't a [major] dip; I had laid the spirit level to show the approximate gradient.

widler, that's pretty much what I was thinking but was concerned about the SLC pooling at the lowest point. From what you say, using a thicker SLC mix and trowelling it seems like the easiest option. The portion of the ridge nearest to the wall (with the most severe level change) will be covered by kitchen cabinets, so hopefully the remainder will look OK.

I'll be using LevelFlex SLC in another room. Do you think that a thicker mix of this would be suitable for this job? Presumably, it'll have no problem adhering to the mixture of concrete / bitumen residue provided it's primed first with something like a PrimePlus slurry?

View attachment Floorplans and services.jpg

 

[Old Mod]

For some reason Thomas your link seems corrupted.
If it's a jpg u can upload it direct to the post using the upload file option below, if the image is held on the device you're using to post of course.
Thanks.

 

[Thomas Moore]

That's odd; it seems to open when I click it in the post. It is quite a large JPG though so I'm attaching a PDF version just in case, along with a smaller JPG version. Hopefully these will work.

 

[Old Mod]

With a long tile such that you have may cause you bigger issues!
How is it to be laid Thomas?
A lot of tiles of that format suggest a quarter bond or straight stacked.
Reason being that they are prone to warping, producing a bow!
Have u inspected samples?
The floor will need to be as flat as u can achieve or you will have corners sticking up all across the effected area.

 

[Old Mod]

My guess is tho you're after an effect

Like this!

 

[widler]

Thomas, its not a big problem at all,slc doesn't just level itself like it suggests, you have to move it around , it doesn't find its own levels.
With using plank tiles , id chop it back more and re level it, plank tiles like flat floors

 

[Thomas Moore]

Hmm... I'm beginning to wonder what I've let myself in for

3_fall: that's pretty much the effect I'm aiming for! On the plan, the tiles would be laid lengthways, left/right. That's a beautiful result you've achieved, by the way.

I've inspected samples of the tiles and they appear to be dead flat without any noticeable bow. Of course, I don't how they'll react after being laid for a period of time.

If the floor needs to be flatter in order to make a good job with the plank tiles, would you recommend using a grinder to reduce the level of the higher section?

 

[Old Mod]

Well if your tiles are true now, they'll stay that way!
U can reduce the height of the area in several ways.
U can hire floor scabbler which is way I'd prob go!
Sod being on my hands and knees chewing rubble and dust haha
Or u can buy grinding cups that fit to an angle grinder or an SDS chisel even.
If you're able to put time and effort in, it will be worth it..
Laying your floor will get easier with ever mm u remove to achieve an even surface.
Doesn't need to be level exactly, just FLAT
And it's better to go slightly lower than u think u need, cos when it comes to the tiling it will be high! Cos it always is! Haha
You can smooth with SLC after if u wish, before u tile.
Dirty messy noisey job, but WORTH IT!

 

[Old Mod]

Craig @widler may know of an easier way tho Thomas.

 

[widler]

Looks like asphalt to me @3fall, i woukdnt grind it or use a scabbler, it will just break it up,me id break it up a few foot(be about a inch or so on too of prob rough concrete) then fill then screed over,l , ive tiled much worse floors than that in plank tiles ,this one was 4 different rooms and a utility, a right pain to do and 40 bags of leveler later (over EUFH as well) looked good at the end, after a far fair big of chiseling up and leveling

 

[Old Mod]

Nice job mate!
Lot of graft tho! Haha
Yeah can't see pics properly I'm outside in bright sunshine so I'm sure ur right mate.
Just looks like 'black' to me out here haha

 

[Old Mod]

Think I'd just add peninsular! Haha

 

[Thomas Moore]

@widler, just to clarify, you'd recommend breaking up the ridge and a little of the asphalt either side then screeding flat?

 

[Thomas Moore]

@3_fall ... don't tempt me! haha

 

[Old Mod]

Slimline base units breakfast bar dining room side, sorted! Haha

 

[Thomas Moore]

If only it were my decision *sigh*