Golden Rules

Points to consider when specifying or constructing with Rods & Mortar:

To install Rods & Mortar successfully, preparation, planning, following the golden rules and understanding the reasons for each accessory is crucial.

The golden rules of building with Rods & Mortar

Glass block walls are self supporting, but not load bearing. In addition to their own weight, they can withstand wind loads, horizontal live loads and impact loads. A lintel provides the head for the panel to be anchored into whilst ensuring no downward pressure is placed on the glass blocks. 

Openings must be square and perpendicular and the opening dimensions must be designed to suit glass block modules. Glass blocks cannot be cut like masonry bricks or tiles.

Glass block walls are connected to the surround by reinforcement bars being inserted into pre-drilled holes (or panel anchors). For best integral strength, panels should be installed into a four-sided pre-prepared opening. The opening can be timber, brick, steel, concrete or block work. 

Between the opening and glass blocks it is essential to incorporate expansion joints to the perimeter to allow the panel to expand and contract freely with temperature change. The foam should not be bridged in order to freely absorb the panel expansion. The expansion material should not be bridged by mortar (render/plaster) and caulked with Rods & Mortar expansion joint sealer (fire-retardant in fire-rated applications).

Rods and Mortar glass block walls are generally constructed with 10mm joints, other spacers are available for 80mm-thick blocks (such as 6mm x 6mm and 6mm x 10mm) to achieve a narrower joint for aesthetic purposes or for smaller openings also ideal for creating curved panels when a tighter radius is required. With the inside vertical joint being narrower the external vertical joint will also be reduced.

Glass blocks should not be installed when the surrounding temperature is 5^OC and falling or 30^OC and rising.

Using standard glass blocks the maximum panel size without intermediate support or slip joints is 25m²,with no dimension exceeding 6m in either direction. For TF30 and TF60 fire blocks, the maximum panel size permissible is 9m² (in line with test specification).