Do I own photos I took at a job site while working as a contractor for another company

As a basic premise, a person who takes photographs becomes the owner (absent a written agreement to the contrary) of the legal copyright interests in and to the photographs taken and thus, as the owner, has certain legal rights to use of the photographs.  However, there are various legal principals that may limit or restrict the basic premise set forth above.  Based on the facts that you have presented, I would have a number of additional questions in order to be able to try to answer your questions.  For instance, I understand you were an independent contractor working as project manager on a jobsite.  The company that employed you may very well have an agreement with the owner/developer of the property with regard to photographs of the property, development of the property etc, such that your employer had no right to have you or anyone else take photographs (even if the employer did not know you were doing it).  Similarly, many construction/development contracts contain specific provisions pertaining to intellectual property rights including architectural designs, construction plans and drawings, etc.  Many owners/developers of properties specifically restrict and control who has the legal right to take photographs of a project under development and where and how those photographs can be used.  If your photographs contain an image of a company name, logo, trademark, you could have another issue concerning misuse or infringement of another's trademark or other IP assets.  In short, the specific answer to your question is likely to depend on the specific facts and circumstances of your situation, and not entirely on what you did or did not sign with your immediate employer.  I would need to have more information to best respond to your inquiry.