EMB ERJ 135 ER/LR
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Provided Assistance; Flight Crew Landed As Precaution; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; Flight Crew Returned To Gate; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft
Upon initial climb out of ZZZ on the R1 RNAV departure operating Flight XXXX ZZZ - ZZZ1 I noticed that the flight deck seemed much louder than usual. We double checked the security of all windows and proceeded with the departure. Monitoring the cabin altitude we noticed that the cabin altitude kept climbing as we did. Once we reached 11 thousand on the departure the cabin altitude was at 4000 and rising. We leveled off at 13 thousand to see what the pressurization would do. The outflow valves never closed and the cabin altitude kept rising. The collective decision was to notify ZZZ2 Center that we would like to precautionary return to ZZZ. After informing ATC of our issue they gave us radar vectors back to ZZZ and a decent clearance to 10 thousand feet. Center ended up declaring [for our] aircraft in order to get us priority vectors back to the airport. Upon landing the fire trucks and airport ops waited for us to vacate the runway to check on the passengers and flight crew. No injuries were reported and passengers were safely deplaned and escorted inside the location with out incident.Possible failure with some part of the pressurization systemThe crew communication and CRM decision making was exceptional and was all handled with utmost professionalism.
First Officer reported an air turn back after cabin would not pressurize.