This paper reports on the gas barrier properties of a range of different coating materials after periods of up to 3000 hours accelerated weathering. The most successful coatings were those based on methacrylates, methanes, pigmented styrene acrylates, water-based acrylics, emulsion, and ethylene co-polymers. Work on the evaluation protective treatments for concrete is continuing. For a second paper on this topic, see <i>AATA </i><b>25-1126</b>. -- AATA