Projector Mount: Normal standard ceiling for commercial and residential ceiling height is 2.4m or around 2.7m to 3m. Ceiling height for commercial office is around 2.7 meters to 3.6 meters or more. To determine which projector mount do you need, work out how much drop do you need, how much weight is the projector. Some large projector mount is for large venue projector only and may not fit other projectors. Please choose accordingly.