Replacing mortar with adhesive offers a solution to one of the greatest limitations to the use of brickwork - the fact that it is strong in compression but weak in tension. This weakness in tension is due to the bonding characteristics - or adhesion - between the bricks and mortar.
In traditional loadbearing brickwork, it is completely acceptable.The design philosophy for masonry engineering is to ensure that high compressive loading is present with minimal tensile loading.This should not be difficult to achieve since the loads from the floors and the roof are compressive. But with modern cavity-wall construction, the outer leaf of brickwork carries no loads other than its own weight.This makes the problem of tensile loading critical when considering wind load.As a result, modern cavity walls rely heavily on fixings, ties, shelf angles and lintels.All of these have an effect on the cost of the wall, as well as on the skills required and the complexity of construction.
In this situation using masonry adhesives instead of mortars offers considerable advantages.This form of construction is not a new one; it was developed in Holland about 10 years ago for a number of reasons:
to improve the working conditions for the bricklayer and to 'raise the profile'of the job;
to create a high-tech appearance - a new look with thin sharp joints.
In terms of design performance, there are two major benefits:
the brickwork has a high tensile strength;
walls built in thin-jointed masonry have a high resistance to rain penetration.
One of the first notable projects to incorporate the masonry adhesive system was the Belgian national football stadium, the Heysel Stadium.Other projects soon followed, and it is no longer unusual to see projects using this technique. The high tensile strength is particularly beneficial to designers since it allows them to eliminate structural support systems, beams and lintels.
The strength is provided by the masonry itself.
Hanson now provides a range of products suitable for the system, in particular a brick range which is 297mm long by 97mm high.With a 3mm masonry joint, these products give a convenient modular dimension (300 x 100mm) allowing simplicity in construction and in the setting out of the masonry.
There are a number of training courses which provide a bricklayer with the additional skills to carry out the adhesive process, although it must be emphasized that it is a very straightforward operation.