It was set up as two sections that could be pretty easily isolated from one another to convert into two separately rentable units.

This excess heat retention can also affect the integrity of the substrate such as plywood.Lastly, if there is a leak from somewhere in the system, it can be very difficult to isolate and repair this because the water can enter in one area, and ride the layer below to a totally different area before appearing in the home. 

They make a studio apartment look like a castle.The other obstacles to overcome are sanitation, zoning and the inevitable complaints from neighbors about dragging down property values.The solution to the neighbor issue ,I think, is to situate the development far away from the others, but that would isolate the people I'd be trying to help.Bottom line - I don't think it's a viable solution here. 

Based on your description of the problem, the bolckage seems to be isolated to the 3rd floor drains after the tub and toilet drain and before the main drain. 

@James Masotti  Cirrus SR -22  NA   ( Normally Aspirated)pleasure and business.. being isolated in the northwest its a great time machineI can be in the SF bay area in 2.45 hoursSalt lake city area 3 hours.La and Vegas 5 hours.Montana in 2 hoursbritish Columbia 2 to 3 hours depending on where I am going.Endurance is regulated by Bladder..

But unless the USA manages to become an island of financial isolation, most of the ROW will get hit worse, which would prompt some kind of global solution. 

I was unable to get a pressure build up in the system and explored for possible leaks, I had already isolated the disconnected pipe and filter so they were not the cause.

We are no longer an isolated economy.

This may need to go under the dumb question category.I understand Duplexes are not the ideal long term investment, unless you control the street or are in relative isolation amongst houses, etc..I submit to needing to save a large amount of cash to really establish myself in MFRs (4) and eventually commercial.

Eddy, as a laymen will make a rational decision based upon his own bias and desires to continue to eliminate or simply isolate one of the 5 investments to make.