Cornerstone is New York City's premier expediting and building code consulting firm. We have two decades of unparalleled experience with NYC building codes, which guarantees our clients receive the highest level of personal attention.In addition to expediting paperwork, we serve as the catalysts for your construction projects. Our design expertise will make sure your designs are up to code, correcting deficiencies along the way. We even help you win approvals and comply with the law after the fact.We are the leaders in knowledge. Know-how.Relationships.And Results.