+1 on @Chris Winterhalter comments.
Another thing that should be considered is the impact on tenants during construction. This is an issue our clients pay very close attention to when renovating any kind of building with tenants. Even the tenants who are in units not being worked on will be affected; dust, noise, parking, utility outages, etc. And remember contractors are optimists, projects rarely complete on schedule. Undiscovered issues, material availability, labor shortages and worst of all changes* in the design or the scope after construction is underway are things that through no fault of their own cause contractors to miss deadlines.
*At the construction company I owned I would tell customers that there are four main levels of cost in construction, each a magnitude of cost higher than the preceding level:
- 1. Manufactured; built in a factory and shipped to the site.
- 2. Production; where hundreds of similar buildings are built at a single site.
- 3. One-of-a-kind (used to be called custom but that term has been co-opted by production builders); building something that's never been built before... and
- 4. By Change Order.