Sand with a medium grit sandpaper to create a uniform surface that s not too smooth.
Tiling onto uneven walls.
Thoroughly vacuum the area and give the wall a once over with a damp sponge or cleaning cloth.
First chip the bumps cracks and dents on the concrete wall with a hammer.
For an uneven concrete floor a floor leveller will solve all your problems.
There is also a spot near the window trim where the wall appears to be built up too much enough so that the tile could end up proud of the trim which i m pretty sure won t look so hot.
Back buttering is a trick used for tiles of uneven thickness like ungauged slate or handmade tiles extremely large tiles or for tiles being installed on an uneven surface.
Self levelling compound for an uneven floor.
Once the cement is dry apply the bonding agent that should give the surface a rough texture.
Level those uneven walls.
Things you will need measuring tape tile wet saw leveling spacers and wedges trowel thinset mortar rubber mallet grout grout float grout sponge.
Use a flat scrap of wood to even and smoothen out the surface and let this dry for a few hours or overnight.
Seal the walls with a skim coat and let it dry thoroughly.
The mortar is spread.
You want the tile adhesive to have something to grab onto.
Then flush and fill the areas with cement.
Plastering the walls is the best way to ensure that the walls are nice and even.