How much will it cost? — More than you think.
How long will take? — Longer than they said.
Seriously, If you have not done this before (negotiated a lease and/or managed a build-out) get some advice.
Market conditions vary quite a bit. In most places right now though, good tenants are rarer than good locations. In those conditions, the landlord should be covering AT LEAST the cost to bring the space up to basic commercial utility. That means the cost of floors, electical, plumbing, ceiling, lights etc should come from the LL. I would suggest that you seek to have the work to be done by the LL defined rather than the $$s to be contibuted. That way, cost overuns on that work go to the LL. If you accept an allowance for those things overruns are your responsibility.
In today’s environment (again, most places, not all) the LL may be willing to give you an allowance ABOVE AND BEYOND the basic build out.
You should not pay rent until you can open for business and you should not be subject to delays in areas you do not control.
if you are in a good cash position, be flexible about how the LL contributes to these things. There are several ways to do it:
- LL writes a check
- LL provides a rent holiday as an offset
- LL offers reduced rent (below market rate) to offset.
There a number of other money buckets in a lease. Be sure you are paying attention. Hire an attorney.
Last thought: a location that is already a restaurant will be a LOT cheaper to convert.