At our passive house in Brooklyn, much of the existing structure repair is complete. The interior side of the exterior brick walls has been repaired and parched with mortar.

As a next step, a liquid air barrier is applied which will become part of the air-tight building envelope. The air barrier looks similar to white paint, but has special elastic properties resisting cracking. Air tightness is one of the two main characteristics of a passive house, together with very good insulation of the exterior envelope. To reach a high degree of air tightness, application of the barrier needs to be done very carefully, especially around the many obstructions and penetrations in this old structure. Kudos to the construction company, R Sutton Co., which has been working through the various conditions on 6 floors of the project!