An alcove for conducting molten glass to a plurality of forehearths for delivery to glassware forming equipment, comprising a series of zones with a trough extending through the zones and a barrel vault roof over the trough in each zone, the vault bearing on blocks at the top of the sides of the trough carrying burners, the vault having keystones formed to provide side channels over side portions of the stream of molten glass in the trough and a central channel over the central portion of the stream.