Removal of stubborn oil stain on concrete floor before tiling - Tile Advice

[ktscarf]

Hiya,

I am in the process of preparing a concrete floor in my mum's house for tiling, and have found that cooking oil which was spilled on the carpet years ago has gone right through, leaving some stubborn stains.

I have already tried

• Sugar soap/detergent
• Mix of sawdust and white spirit, covered and left for 48 hours
• A degreaser product scrubbed and rinsed

Each of the above has removed some of the oil, but a fairly large stubborn stain still remains.

I've attached pictures of before and after the above treatments, the one ending in 2310 is the after - although I suppose hopefully anyone reading might be able to tell just from looking!

Does anybody know if what I have done should be sufficient, or should I be aiming to completely remove the oil stain?
I am just concerned that, long term, the oil may compromise/break down the adhesive and lead to cracked/damaged tiles.

Thanks for taking the time to read this!

 

[Dave1033]

Shouldn’t be too much of an issue

However if concerned I would Abbrade the surface (scratch the top layer off)

Some adhesives can go up to 20mm in isolated areas so you wouldn’t even need to use any leveller etc..

Are you going to be using a decoupling mat?