Hebel Research Part 4 (Installation)

Hebel Adhesive

Hebel blocks are laid using premixed Hebel Adhesive. The Hebel Adhesive should be prepared in accordance with the instructions on the packaging. Importantly, the adhesive should not be retempered as this will have a detrimental effect on the bond strength. After thoroughly mixing the adhesive is ready for use.

Installation of Blocks

All blocks should be brushed clean of dirt and loose particles. Hebel Adhesive is then applied to the vertical and horizontal surfaces using a Hebel trowel of the same width as the blocks. Vertical and horizontal joint thickness should be approximately 2-3mm. The consistency of the adhesive should be such that is flows easily through the teeth of the trowel. When applied, the ribs of adhesive should maintain their shape and not collapse. A thin mix will result in poor joint strength and is indicated by collapsing ribs. A dry mix will result in the ribs not bonding to the AAC surface and peeling off the block. The adhesive must cover the whole vertical and horizontal surface of the block to maintain wall strength, sound and fire rating. All perpends should be fully covered with the adhesive, made tight and a full contact achieved.

Excess adhesive should be removed from the block face as laying proceeds. The vertical joint of the lower course must be staggered at lease 100mm relative to the vertical joint of the overlaying course.

Horizontal Surface

Hebel does not recommend a horizontal surface finish of its products in external environments. As water could pond on the surface and penetrate the coating system. In the case of a horizontal finish, Hebel recommends that the surface be treated with a waterproof membrane or metal flashing/capping. The designer should ensure that the waterproof membrane is compatible with coatings, finishes, environment conditions, AAC substrate, etc. The main areas to detail correctly are roof and floor panels, window sills and the top of parapets. Importantly, the AAC substrate should be prepared in accordance with the membrane manufacturer’s instructions.

Figure. Hebel Installation Checklist