Why use a consultant?
The staircase is the largest single item in any house, it has to meet the landings correctly and is the foundation for the handrail.
Many staircase designers and builders design the stairs without thought to the handrail or the floors that the staircase has to interact with, this can lead to many problems once the stairs have been fitted. This may mean you do not get the handrail to flow correctly and the stairs may not meet the walls at the right point or even how the underside meets the ceiling line.
wether your stairs are traditional or modern the geometry is the key. Geometry of the staircase also controls any features you may want, such as Monkey's tail or offset opening caps set over newel posts.
Getting the stairs designed correctly can save thousands of pounds in correcting design errors at a later stage. the stairs should be designed before the hallways are set out with doors and skirtings to ensure a satisfactory outcome.