A bathroom is a question of where the water can go, and in Kettering the answer depends on which grade of house you are working in.
On the smaller Victorian houses the upstairs joists were sized for a bedroom and nothing more, and a filled bath on a tiled floor is a considerably heavier load than the original design contemplated. Where a waste run means notching or drilling those joists there are permitted zones, and on a marginal floor we will strengthen rather than cut. This is the single most common place where a bathroom on this stock goes wrong.
On the larger houses the floors are heavier and the rooms bigger, which brings a different problem: a bathroom in a big Victorian room needs heating designed rather than a towel rail chosen, because the volume and the external wall will beat an undersized radiator every winter.
The soil stack runs externally on the older stock, and on a street facing elevation inside a conservation area, moving it is a permission question rather than a site decision.
Ventilation and tanking are not optional. An extractor discharging into a roof void puts moisture straight back into the building, and tiles and grout are not a waterproof layer. Our bathroom installations page sets out what a full refit involves.