1. Begin at the Free Library of Philadelphia.
-- In the map room, as for the folder that indexes the map holdings. This will tell you which maps exist for your area and when those maps were made. Look at a range of maps over a fairly large period of time. This will give you a complete a record as possible. Also, make sure to ask for the maps that contain owner information. These names will serve as a good starting place for later work. While you are looking at the maps, be sure to look at the key that denotes size, building material and class.
-- In the print and picture room, ask the librarian for any images that pertain to your site. They will bring them out to you.
2. Then go to city hall, room 164. This is the map room. Look at the map on the wall for the plot number of your site; this will lead you eventually to ownership records. The plot number will look something like 4S13 or 2N21. The S or the N refers to north and south. Then ask the person behind the desk for the maps pertaining to those numbers. They will bring them out to you. Those smaller maps will have plan numbers on each building. This will enable you to specifically pinpoint your building.
3. Then go to the Department of Licenses and Inspections. Go downstairs to the Central Clerical office and request to see the microfilm for building permits. These are listed alphabetically by location and will list permits beginning in 1865. On the microfilm you will see the type of permit that was issued, its date and its number. Be sure to write these down, as you will later need them in order to request the actual permit forms from the city archives.
4. Then go to the City Archives.
-- Ask the person behind the desk for the transfer sheets using the plan and lot number you found at City Hall. These transfer sheets will provide you with a record of building ownership.
-- Then ask for the permit forms (such as new building, alteration and demolition) using the permit numbers that you got at the Department of Licenses and Inspections. These will show you how the building has changed over the years.
-- While you are there, look through the Building Directory and the City Directory for any names that you have found to be connected to your property. This information may give you further context about your site.
-- You might also find it helpful to look for any photographs of your site. Look in the photograph index, which is arranged alphabetically, for your folder number. Then bring this to the person behind the desk.
5. Then go to the Historical Society of Pennsylvania. Look through the fire insurance card catalogue for any insurance surveys related to your site. You can find these either on line or in a printed version. These surveys are listed alphabetically. Make sure to record which company conducted the survey (Mutual Assurance, Philadelphia, etc.) and the policy number that was given.
6. As a final step, look through the 1880 census -- which can be found online at www.familysearch.org -- for any names that you have previously come across.
This process can be somewhat tedious as names are often spelled differently in different places and addresses are often listed by city rather than by specific location. However, if you do find the right name, it can add a further dimension to your site.
*our notes in pdf format...*