Can this be done in this building, at a cost and with a disruption the owner would accept, and what would it actually involve? That is the whole exercise. It is deliberately carried out before design money is committed, because the expensive mistake in vertical transportation is not choosing the wrong equipment - it is discovering halfway through a design that the thing you set out to do was never going to work in the space available.
Space and structure first: is there a shaft, can one be created, what does the existing structure allow, where do the loads go, and what happens at the pit and the overhead. Then services: power supply and switchboard capacity, fire and emergency systems, ventilation and cooling. Then the building in use: how the works would be staged, what access is lost and for how long, and how occupants with limited mobility are supported while it happens.
Compliance runs through all of it. Adding or extending a lift usually brings requirements that the existing installation was never asked to meet, and those need to be identified at the start rather than discovered at certification.
A feasibility study that always says yes is not a study. Sometimes the answer is that it can be done but the cost and disruption are out of proportion to the benefit. Sometimes it is that a different intervention gets most of the value for a fraction of the money. Sometimes it is that the proposal works, and the useful output is simply a clear scope and a realistic budget to take to the next stage.
We would rather tell you not to proceed early than watch a scheme collect design fees on its way to being abandoned.
A written report setting out the options examined, what each would involve physically, the compliance implications, an indicative cost range and programme, the risks we can see, and a recommendation with the reasoning behind it. It is written to be handed to an architect, a builder or a committee without needing us in the room to explain it.
Not sure yet whether the building needs a lift, a second lift, an escalator, or all three? How buildings move people is our free 3D explainer for exactly that stage: have a look inside both, then see which one your building calls for.