Abstract: An end cap for preventing ingress of moisture to the end face of a structural beam, wherein said structural beam comprises metal, stone, concrete, reinforced concrete, or a mixture thereof; said end cap comprising: (i) an end plate having a shape matching the transverse cross-section of said structural beam; and (ii) a skirt for holding said end plate in position; wherein said end plate and said skirt comprise or consist of a material for preventing transmission of moisture.