There is a major difference to a after builders cleaning service which is done at the end of a new build or renovation, compared to a clean which you'd get at your home on a regular basis. Building is a very messy job, and a clean is necessary once the building process is complete to make your new renovation, extension, or new home presentable and clean.
This is the initial stage of the builder's clean. It involves removing debris, dust, and rubbish from all of the building's surfaces. Usually, this is done part-way through a construction project (e.g. cleaning all of the plaster form the floors so that tiles may be installed). Many builders use this service as well before having their client walk-throughs to detect any trade defects.
This final stage is what really sets apart a professional builders clean from a regular home cleaning. The stage involves removing trade defects such as paint marks from the floorboards, detailing tiles, removing grout haze from tiles, straightening grout lines, splatter from windows and more.
This final detail clean will provide your house with a showroom quality finish. It is very easy to tell when a new house has been given a final detail clean since there is a huge difference.
This stage takes the longest amount of time given all of the detail that is necessary. Unfortunately, there are many cleaning companies that leave that part out of their quotes in order to make their prices appear to be cheaper or due to the fact that they don't know what a professional builders clean should include. Or even worse, there are cases where some cleaners have caused permanent damage to a house by unnecessarily using harsh chemicals without having the necessary experience to do the job right.
This is a very general outline of what a builders clean should include. You can go here for a more detailed builders clean specification.