I am facing a leaking common area bathroom from my neighbor above in a standard 1000sqft apartment. Contractor advise to do chemical PU injection from below (IE my unit), I was wondering if this solution is better than doing the epoxy membrane from the toilet above?

Also the price quoted was RM1850 for one bathroom, not sure if this is in line with the market?

Advice and opinions are all welcome.

what i meant was comparing the effectiveness of PU injection from below VS epoxy coat from above. Epoxy coat does not damage tiles since it is applied on the tile surface only.

my concern is the PU injection from below may cause situation whereby the water is stopped from flowing down, but may dwell in the cracks and crevices plugged by the PU and over time cause other problems, or worse the water will just divert to another area of my unit, because water always finds its way in time. Or later on (maybe years later) new micro cracks appear and cause the leak again.

Just did a comparison. PU injection RM1850, epoxy flake rm850 and addresses the problem from the root cause (ie from the leaking bathroom itself). With this price/benefit ratio, can someone share what is the advantages of PU that cause more than 2x the price while solving the same problem?

Of course the scenario being addressed here is limited to bathroom leaking, other scenarios maybe PU might be more convincing.

Not sure if serious comment or troll, but this product looks like its only used for locally sealing known cracks. Also, identifying the leaks is probably better done by expert.

One advantage I can think of for PU injection is if you meet an uncooperative neighbor upstairs and have no choice but to solve the problem from below.