I pulled the vinyl tiles on my bathroom floor (not the shower) and scraped off the black mastic. I spray water to avoid dust. After I am done, most of the floor dried off very quick, but there is a section of the floor is not. It has been 5 days and is still wet.
Between the dried and wet area, it seen like there is a blurry mark. I think the wet area is the area which was cut out and patched. Inside the wall, there are some water piping. This area used to have a bathroom's sink. I touched the pipes, they are dried.
There is another narrow area, which also looks wet. It is right under a wall (separate from the sink area). When I took out the moulding (base board), it wasn't wet. The wet is from the water I sprayed when I grind the floor surface.
In the pics, you see some white stuff. This white stuff start to show after several days. If I leave it alone, it'll grow taller and some will look hair-like, to maybe 1/2 inch. If I squeeze it, it's like powder. Is it called efflorescence?
Do you guys think I can put porcelain tiles on this floor? Will this stuff damage the thin-set?
