a substantially rigid and substantially waterproof casing, said casing defining a casing external wall, said casing external wall having a casing wall inner surface, said casing defining a casing inner volume and a filling aperture extending into said casing, said casing being positionable in a predetermined relationship relative to the building wall; and

a filler, said filler being provided within said casing inner volume, said filler substantially contacting said casing inner surface for minimizing an amount of air between said filler and said casing external wall;

wherein:

said casing includes a casing base positionable substantially adjacent said ground surface, a casing upper portion and a casing intermediate portion extending between said casing base and said casing upper portion;

said casing inner volume includes an inner volume first section extending from said casing base up to a baseboard first filling level and a casing inner volume second section extending from said baseboard first filling level up to a baseboard second filling level;

said filler includes a first filling material filling said inner volume first section and a second filling material different from said first filling material filling said inner volume second section; and

said casing and said first and second filling materials are positionable so that said first and second filling materials are in substantially lateral contact with the building wall.