How do i prepare my missing grout tile floor ready to start stencil

Hi Sheila, you can remove the crumbling grout with a grout remover tool. They are about $10 at any home improvement store. Then regrout the area that needs it. When you rinse grout, it is very important to keep rinsing until the water runs clear and then get fresh water and rinse two more times. Give the grout a day or two to dry and you should be ready to go!

Home depot get more grout mix it fill in with a sponge squeeze into cracks make shure its all filled it when dry then stencil make shure to totaly rinse off grout on tile for stencil.

Remove the grout that's crumbling. Regrout and let it cure. Then you can paint.