Influence of horizontal joint on the thermal properties of single-leaf walls with lightweight clay blocks

In the present work, single-leaf walls built of large-format lightweight ceramic clay blocks are taken as the starting point. Several types of block, tongue and groove systems and horizontal joint are examined. To compare the improvements provided by each of the systems studied in terms of energy, the equivalent thermal transmittance levels of the shell of the wall are compared.Recent studies have optimised the geometry of the voided clay bricks [7], [8], [9] and [10] and the tongue and groove system [11], but the influence of the mortar horizontal joint has not been studied. The mortars suppose one of the principal weak points of the wall due to his high conductivity, his penetration and his great thickness.Calculations are drawn up in line with Spanish UNE [16], AENOR [14], European EN [17], [18] and [19], and international ISO [20], [21], [22] and [23] standards.It is concluded that the type of exterior wall used has a great impact on the energy consumption of buildings. By using blocks with the optimal geometric distribution, optimal vertical joints and thin horizontal joints energy savings of up to 37%.

► Horizontal joints are the key element in improving insulation in outside walls.
► A wall built with thin joints and pre-ground blocks has major advantages.
► The heat dissipated through the horizontal mortar joints is greatly reduced.
► The thermal performance of a wall with thin horizontal joints improves 19–24%.
► This means less energy consumption and a proportional decrease in GHG emissions.