Wall Widths 100-215mm
Box lintels can be used for internal or external openings and with a variation of wall thicknesses. The Keystone box lintel has perforations along its length acting as a plaster key. As an optional extra Keystone box lintels can be insulated. The Keystone box lintel is designed to carry the full load of wet masonry as soon as it is installed.
Box Lintels must have a minimum end bearing of 150mm on each side of the opening, bedded on mortar. Level the lintel along its length and across its width. Masonry built must be laid on a mortar bed and all perpendicular joints to be filled with mortar. Care should be taken to avoid shock loading on box lintels when used in conjunction with concrete floors or other heavy units.