With the expanding size of additive manufacturing products, research pioneers start to explore 3D printing in the construction field. For 3D construction printing, quality means safety, cost, and efficiency. However, it is challenging to ensure quality via defect detection and deviation correction during the construction printing process. Conventionally, defect and deviation still rely on the quality check after printing is completed or on-site manual monitoring, which could cause either a waste of material and time to abort printing or lagging adjustment for printing settings after obvious defect appeared. To overcome these challenges, we propose a point-cloud-based approach for real-time 3D construction printing defect detection using a 3D camera and cloud-to-plane distance to evaluate printing layer integrity and compare printing results with CAD models. We also define different types of defects and deviations that can cause printing failure. Additionally, we feedback detection output into a closed-loop controller for updating the printhead motion. Our experiments show this joint printing and detection process handling various defects and deviations.