The short answer is: Enter the portion of your building that is under construction as a separate Property Use (you should probably use the Property Type = Other*). For the Use Details for this new Property Use, enter: Weekly Operating Hours = 0 Workers on Main Shift = 0 Number of Computers = 0 Be sure to include the square footage under construction, in your property's Gross Floor Area (on the Details tab, under Basic Information).
*The longer (more complicated) answer: While you can always use the "Other" Property Use Type, it could affect your ability to get an ENERGY STAR score. If that's a concern for you, see if this helps: How are you defining "under construction?" If the “under construction” part of the building really has not been fully built (ex: no electricity, heating/cooling, or water), then the Property Use Type should always be "Other." If you are in-between tenants or re-configuring the space for a new tenant (and you have electricity, heating/cooling, and water), then you may be able to create a "Vacant" Property Use: If your main property type is Office, Bank, Financial Center, Courthouse, or Medical Office, then it depends on the future Property Use Type for the space under construction: If it will eventually be the same Property Use Type (e.g. Office, Bank, Medical Office, Courthouse) –> treat it as a vacant space. If it will be a different Property Use Type (e.g. Retail, Hotel, Residential), then it depends on the size of the space: If the space under construction is less than or equal to 25% of the total -> treat it as a vacant space. If the space under construction is more than 25% of the total -> enter it as “Other” If your main property type is NOT Office, Bank, Financial Center, Courthouse, or Medical Office, then the Property Use Type for space under construction should always be "Other" because Portfolio Manager cannot accurately account for this type of space.