This is a question that haunts builders a lot and there is a good reason for that as well. Waterproofing can often be very specific science, but it can also change with circumstances. This is especially true for sanitary waterproofing, an area that requires a careful approach. However, the fact of the matter is, the question itself is not a definitive one. Depending on the location and the application, you could end up going either way.
If bathroom waterproofing was something that you could only do before floor layout, there wouldn’t be waterproofing services offering waterproofing bathroom floor after tiling. The point is, you can do it either way, but depending on when you do it would change the type of work you can do.
For example, going for cementitious waterproofing would only be possible if you did the waterproofing part before laying tiles. However, you could still add a bathroom waterproofing membrane in some cases after tile installation as well. There is also the option to go for exterior waterproofing of the bathroom floor, walls, and ceiling. It is only as effective as the person doing the said job. Speaking of which, the most important aspect of sanitary waterproofing is the company responsible for the job.
A lot of waterproofing companies claim to perform great but that is not always true. For people looking for waterproofing companies in Dubai or other Emirates, there is still a viable solution. Proper Waterproofing is a name you ought to remember for the best quality waterproofing solutions at a reasonable price in the UAE.