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Architectum Magazine
Modern architectural aesthetics with thin jointed masonry
Gluing facing bricks: technique of the future
Important technical, economical and architectural advantages
With the technique of gluing TERCA clay facing bricks Wienerberger has set completely new accents in façade design. Architects have praised above all the playful new possibilities this façade design offers.Wienerberger is convinced that gluing of façade bricks is the technique of the future; the bricks are not affixed to each other with ordinary mortar but rather with a thin layer of glue. This creates all kinds of new perspectives, both technical and creative.
Technique and processing
The technique was mainly developed in the Netherlands in close cooperation between all involved parties: brick and mortar industry, building firms and the Dutch building and construction research institute TNO. Because of the great variety in the range of TERCA facing bricks many different kinds of adhesive mortar have been developed. The processing of these adhesive mortars was also studied carefully, resulting in the creation of different application methods. Thus, adhesive mortar can be applied with a machine developed especially for this purpose or manually, if desired.
Specific characteristics of glued façades
High qualityBased on physical qualities such as frost resistance, strength and stiffness, as well as on the basis of existing references it has been proved that you can do all the same things with the adhesive procedure as you can with traditional masonry.
Extensive constructive options
From a constructional viewpoint the tensile and bending strength of the glued masonry is increasing by the factor three compared to traditional masonry. The structural engineer can use this increased strength in several ways, not only to make larger holes but also for a slimmer construction. An example of this is when we glue the façade bricks on edgeways. The much stronger adhesion of the glue makes it possible to affix relatively large façade holes without concrete or steel supports.
Durability
The glued masonry is also more durable: Scientific tests have proved that these joints positively effect the visual appearance of the façade's ageing – efflorescence does not appear and the façade remains clean for a much longer time.
The adhesive mortar is rich in cement and makes glued brickwork extremely impermeable and water repellent. The larger surface of walls with recessed joints ensures that the façade brick also dries more quickly after a rain shower. UV weathering tests were done along with frequent alterations between frost and dew and they also showed no measurable ageing in this area.
Adhesive mortar
Wienerberger has developed its own processing recommendation for gluing facing bricks. Here are the most important points:
- Any type of façade brick can be glued be it hand moulded, stock or extruded.
- The recommended joint thickness is nominally 5 mm. For façade units with an extremely accurate size, a joint of 3 to 4 mm can be maintained.
- With traditional laying, the standard brick shapes are assembled in a modular manner, with brick dimensions and normal mortar joint thickness. This coordinating brick module is no longer applicable for glued brickwork with 5 mm or smaller joints, with the relationship of conventional brick length and width.
- Façade bricks can provide a range of distinctive bond patterns including stack bond and for those products with adapted dimensions, traditional patterns displaying header and stretcher units can be achieved.
- Depending on the dimensions of the facing brick, approximately 10 to 15% more facing bricks are required per m².
- It is possible to choose a coloured adhesive mortar to match the colour of the clinker.
- We highly recommend mixing the adhesive mortar with a glue pump and a glue gun application. This provides an optimal mixture of the mortar and ensures that the construction technique is achieved satisfactorily.
- Using air cavity as main water barrier you can choose between open and closed vertical joints - suitable detailing must be considered to prevent potential rainwater ingress.
- A successful glued masonry project requires good communication between the brick manufacturer, the mortar manufacturer, the contractor on site, the sales team and the architect and client.
Thin layer mortar
In addition to adhesive mortar, thin layer mortars are also available. They offer the same aesthetic appearance in panelling as glued masonry but they do not have the higher bond strengths of adhesive mortar. They can be applied traditionally with a brick trowel. All other focal points mentioned above apply to the thin layer masonry procedure as well.
