Bathroom Floor retile question

[BasilFawlty]

I am doing a complete master bath remodel, and doing most of the work DIY. I have completed the tub/shower re-tile and it came out great, but now I'm about to tackle the floor. After I get all the old tile and thinset up from the concrete floor (using 7" grinder with diamond wheel and a hepa filter shop vac) I am going to use a decoupling membrane (probably Schluter) before I put down the 12x24 porcelain tiles.

Concern: I have a 1/8" top 1/4" wide crack that runs about 6 feet across the floor.

Question: Assuming the floor is level, would it be ok to just put the membrane down over the crack, or should I effect some repair on the crack first? If so, what is the best process to repair? I'm thinking clean up with a grinder then use something like Quikrete crack sealant (but not sure if that would be compatible with the thinset used to lay down the membrane).

Any suggestions?

 

[MG70]

I'm not a pro. but I've done some tiling on floors and in some cases needed to address issues prior to actually tiling. You don't state what your substrate is. Assuming it's a subfloor on joists, etc., I suggest you carefully examine it to see what's causing the problem and correct it prior to spending your time and money on your project. It could be as simple as someone having used drywall screws that have snapped, or not enough fasteners, or the incorrect pattern of fasteners, to hold the subfloor in place. Good luck!