By using the whole house approach! First, our closed cell polyurethane foam core has the lowest perm rating in industry with a density of 2.0 per inch (water does not penetrate foam and will actually bead on the surface). Next, our wall and roof panel joining system utilize embedded cam-locks, (every 2’ along the vertical profile edge) each operating with over 800 pounds of force effectively joining the panels together. A typical panel edge would have 4 cam locks and over 2,500 pounds of force holding the panels together. To complete the seal along the edge profile, minimal expanding foam material (provided) is discharged into the edge profile. The engineered fastening and locking systems ensure an air-tight moisture resistant environment. Additionally, exterior finish systems are specified with moisture resistant materials relative to the climatic conditions.