A gas turbine engine includes a compressor section, a combustor section and a turbine section for rotation on an axis. The turbine section includes at least one row of rotating turbine blades each having a radially outer tip. A blade outer air seal is positioned radially outwardly of the radially outer tip. The blade outer air seal has a central web positioned radially outwardly of the radially outer tip. The blade outer air seal has an upstream mount arm and a downstream mount arm receiving mount structure from a static structure. The static structure has sealing members engaging an upstream outer surface of the upstream mount arm at an upstream seal material and a downstream outer surface of the downstream mount arm at a downstream seal material. A method is also disclosed.