Peter Rohmann Associates Inc. started out by providing Roof Consulting and Inspection services, however roofing, waterproofing and air-seal systems are all very similar in nature. When it comes to the purpose between Waterproofing and Roofing there is often no difference at all other than location. Air-seal systems were developed in the early seventies with the introduction of the rain screen principle and the addition of substantial vapour barriers (retarders) which were eventually referred to as air barriers and finally air seal membranes. Wall construction is basically no different from roof construction or terrace construction other than the fact the surfacing is different and the plane is vertical rather than horizontal. The main reason Peter Rohmann Associates Inc. also specialize in air seal systems is that these materials ultimately provide continuity with the roofing and/or waterproofing, and air barrier system.