Repair Floor Under Toilet. Turn water off to the toilet by closing the valve on the water line behind it. Hire a floor repair company that will exceed expectations.
Repair dry rot in the floor around toilet. See even more great ideas at wwwCAm. How to Repair the Floor Under a Toilet Remove the Toilet.
There is also visible glue atop the seam.
Cost to repair this type of damage will vary greatly depending on the extent of the damage and the type of flooring. The cost of this repair varies from 400 - 500 for removing the toilet lifting the flooring cutting removing the subfloor around the toilet replacing the subfloor adding in additional support and reinstating existing flooring toilet etc. Cut support lumber usually 2x6s or 2x8s to fit between the existing floor joists on each side of the hole and install them with long screws leaving half the width of the support lumber under the existing floor. Disconnect the water supply line from the toilet tank.
