To install a sink, which is in addition to the original. There must be a hole wall, cement pipes and waste water from the toilet, disabled persons behind.In the list of sinks may be a very unnecessary.
You can also install the sink. Which is an addition to the original. Walls need to be drilled The water and wastewater from bathrooms, disabled back from the list sinks probably will not need much.
Install basin, it can be done. Which is made from the original to penetrate the wall plaster. On the common bile duct and waste water from the bathroom disabilities behind