Process and cost factors
What gets discovered once the old suite comes out
Removing an old bathroom exposes decades of previous work, some of it done properly and some of it not. This is the point in the job where the original plan is most likely to need adjusting.
The moving parts
Point 1
Old lead or galvanised pipework is sometimes found still in use behind a more modern-looking bath panel, and needs replacing rather than reconnecting.
Point 2
Timber floors around a WC or shower tray are a common place to find softened or rotten joists from long-term small leaks.
Point 3
Previous tiling is often found stuck directly to plasterboard with no waterproofing layer beneath it at all.
Point 4
Redundant pipework from a long-removed fitting is sometimes left capped inside a wall and needs tracing before it can be safely left or removed.
Common questions
Does finding a problem always mean extra cost?
It usually means extra work of some kind, but a good fitter will explain the options rather than assuming the most expensive fix is the only one.
Can this be checked before the job starts?
Partially, a survey that lifts flooring or opens an inspection point where possible reduces surprises, but some things only show up once the suite is out.
Not ready to book, just weighing it up?
That is fine, questions at the thinking stage are the cheapest ones to ask, and they usually save a change of mind later.