Just got back from the rental.So the pipe did come apart by its self.I replaced the plumbing tape and the washer a year ago and I found it disintegrated.

Old houses have cast iron pipers that will disintegrate (because of age and/or foundation shift).

The particle board disintegrated and is falling apart.Best solution is to remove the vanity, pull out the bottom, and replace it with a new, solid board.An alternative is to just replace the vanity.

@Andrew Coulton You forgot to include lead paint, asbestos popcorn ceilings/walls and disintegrating iron cast sewer pipes, among other pleasures that come with structures built prior to 1980.​As for foundation, there is more to foundation repairs than just the foundation.

The dip tube inside the water heater was basically disintegrating and the tiny bits would clog up at the faucets.

Old houses have cast iron pipers that will disintegrate (because of age and/or foundation shift).

Im honestly at a loss as to these quotes. 4) See #3, but I honestly just say Im in the middle of an interior renovation, I dont have time to focus on the driveway (for example), Id like a quote please to have the disintegrated asphalt driveway replaced with concrete. 5) This is alluding to work thats started and unfinished. 

You could have foundation issues, or possibly old termite damage where major support beams have disintegrated or maybe support piers that have sunk or fallen over or rotted. 

Old houses have cast iron pipers that will disintegrate (because of age and/or foundation shift).

That means anything that would have been OK if it had been left in service - old knob and tube, for example, that wasn't disintegrated - will now have to be changed out.