Processing of blocks with thick-bed joint

Notes on working with climate light-weight blocks

In contrast to KLB flat blocks, KLB climate light-weight blocks have a height of 23.8 cm and must be processed with a thick-bed joint of 12 mm with light-weight or normal mortar. For this the blocks are set with their slots or chambers downward onto the mortar bed and aligned as is customary horizontally and vertically.
Like the flat blocks, all blocks have a double symmetrical continuous tongue and groove formation (labyrinth interlocking) on both butt joint sides, so the butt joint generally remains free of mortar. Due to the double symmetrical formation the block can be placed without rotation from the right as well as from the left. For better processing KLB blocks have diagonally offset thumb holes as gripping aids as well as recesses aligned outside in the direction of the block axis for receiving a stone clamp when processing the blocks using a transfer tool.
The KLB climate light blocks with thick-bed joints include the KLB flat blocks: KLB full blocks SW1, KLB blocks W3, KLB pillars and shaft blocks, KLB hollow blocks, KLB sound insulation blocks, KLB butt blocks and KLB bay blocks. During manufacturing, in addition to normal-shaped solid blocks divisible blocks and end blocks are also produced. In each block layer there one such block and it can be used accordingly. For processing KLB light-weight mortar LM 21 is recommended from a thermal point of view.
While KLB blocks have a block height of 23.8 cm, KLB solid blocks generally have a height of 11.5 cm. The head sides are smooth. The blocks must always be mortared over the entire area in the horizontal and butt joint. For load-bearing masonry and pillars solid blocks are processed flat, for thin walls and light-weight separation walls generally standing on edge, the block height is then used as block width (wall thickness).
In particular, however, they are meant as supplementary blocks for normal-shaped KLB masonry, where they are used for any partitions. Due to the different deliverable sizes all masonry thicknesses can be supplemented without cost and work intensive cutting or separation work. In particular the 5 DF block can be used for 30.0 cm thick masonry as well as for 24.0 cm or 11.5 cm thick masonry. If you omit the associated 6 DF solid block for 36.5 cm thick masonry, the 2 DF block corresponding to the 24.0 cm thick masonry can also be used. The handy 2 DF block can be used for many tasks and can be described as an all-round-talent. For 36.5 cm thick masonry the 3 DF supplementary block can also be used when bricked next to each other. For reasons of rational processing single block masonry should be used when possible for partitions as well.


KLB solid blocks are frequently used as a supplement in thermally insulating, monolithic exterior masonry and are also subject to thermal stress there. The typical solid block gross density classes 0.8, 1.0 and higher were reduced by KLB by using prepared light-weight concrete aggregates to gross density class 0.60. For mortaring in the exterior wall area the same KLB light-weight mortar is recommended that the rest of the wall was built with. For the interior walls normal mortar is used. KLB building slabs or KLB hollow wall slabs are manufactured and used for light-weight, interior separation wall blocks. They can, however, also be used for partitions e.g. for jamb walls or for surround masonry e.g. shafts.


KLB building slabs are solid blocks without chambers or slots in size 8 DF. They have level butt joints that must be mortared, or a simple tongue and groove system, which remains mortar-free in the butt joint area. The deliverable size is 8 DF, where the length is 490 mm, the width 115 mm and the height 240 mm.


KLB hollow wall slabs display a row of chambers with two or three chambers. They have simple butt joint interlocking, where on one side the groove and on the other side the tongue is formed, as for reasons of small width the typical, double symmetric KLB interlocking cannot be manufactured. The deliverable size is 8 DF, with the length 495 mm, the width 115 mm and the height 240 mm. The strength class is 2, the associated gross density class 0.8.