Yes, nearly all room additions in Las Vegas require permits. Structural framing, foundation work, electrical extensions, plumbing, and HVAC modifications must be reviewed and approved by the local building department. Inspectors typically check foundation reinforcement, anchor bolts, framing connections, fire blocking, insulation, and final life-safety items like smoke detectors. Building without a permit can trigger stop-work orders and fines, and you may be required to open walls for inspection. Unpermitted work can also create problems during resale, since lenders and buyers often verify square footage against permitted records.