 Ancient Roman bricks found in France measured 8" x 8" x 3".The Constantine Basilica in Trier is constructed from Roman bricks 15" square by 1½" thick.There is often little obvious difference (particularly when only fragments survive) between Roman bricks used for walls on the one hand, and tiles used for roofing or flooring on the other, so archaeologists sometimes prefer to employ the generic term ceramic building material (or CBM).