A lot depends on where you are located.  Here in California you would probably have to include costs for seismic upgrades, especially if you are adding HVAC equipment to the roof.  A good commercial estimating source is Saylor
http://www.saylor.com/

regards

Before estimating costs for this renovation, I think you should back up and confirm feasibility of project with respect to existing conditions.

You mention a new second floor to be added .... is there sufficient reserve capacity in the foundation system to sustain these additional design loads?

I assume there is an existing main or ground floor. You should if you have not already attempt to recover the original construction plans.

There should be valuable information on these plans which states the design loads under which the building was originally designed for.

Roscoe's comment about seismic load cases is well taken.

Good luck.

Before estimating costs for this renovation, I think you should back up and confirm feasibility of project with respect to existing conditions.

You mention a new second floor to be added .... is there sufficient reserve capacity in the foundation system and the superstructure to sustain additional design loads?

I assume there is an existing main or ground floor. You should if you have not already attempt to recover the original construction plans.

There should be valuable information on these plans which states the design loads under which the building was originally designed for.

Roscoe's comment about seismic load cases is well taken. Additional load cases and combinations may be required for design.

Good luck.

mbsmith:

We have used the R S Means web site for estimating in the past for budget estimates.  However, we made it clear that no destructive or intrusive testing was included (that is an extra).  

I hope it is appropriate in this forum to ask if anyone out there knows of another renovation estimating web site?

I,ve seen many plans get shelved because no one bothered to estimate environmental costs up front. A lot of time and money was wasted for lack of an asbestos survey, issues with PCB's and lead paint. dk