A moisture vapor permeable metalized composite sheet is formed by coating a moisture vapor permeable sheet-with at least one metal layer and at least one outer organic coating layer. The moisture vapor permeability of the composite sheet is at least about 80% of the moisture vapor permeability of the starting sheet. The composite sheet provides a barrier to air and liquid water infiltration while having high moisture vapor permeability and good thermal barrier properties. The composite sheet material is suitable for use as a building construction wrap such as roof lining and house wrap.
