the invention includes a microbe - mitigating architectural barrier that includes a barrier forming material , and at least one biocide . the barrier forming material may be a bitumen product , an elastomeric polymer and combinations thereof . the microbe - mitigating architectural barrier may be formed by applying an emulsion composition directly to an architectural surface , or may be pre - formed and adhered or otherwise secured to the architectural surface in the form of a sheet or film . the invention also includes architectural assemblies and / or building envelopes that include the microbe - mitigating barrier . related methods encompassed within the invention include a method of preparing an architectural barrier that includes : preparing an emulsion that comprises a barrier forming material chosen from a bitumen product , an elastomeric polymer and combinations thereof , and at least one biocide , applying the emulsion to at least one architectural surface , and drying and / and or curing the emulsion to form a barrier .