Technical Note: Masonry Structures

Technical Note: Masonry Structures

After completing the reinforced concrete foundation slab, the construction continued with the next phase – the erection of the external and internal walls. As in previous stages, we used unfired ICEB bricks (Interlocking Compressed Earth Blocks), i.e. pressed blocks equipped with a pair of interlocking joints. Again, for this construction season, we opted for the variant with a 5% cement additive, which improves the material's mechanical properties (strength and hardness), but most importantly, increases its resistance to termites.

Benefits of using ICEB blocks

The material for the structures was chosen for several key reasons:

• Local availability – The bricks can be produced directly from local raw materials, minimizing the need for transportation. Transport is generally problematic in Zambia and this year was further complicated by the construction of the main highway connecting Lusaka with towns in the north of the country. The production process uses a mixture of water, clay, sand, and cement (as an additive to improve resistance to water, termites, and to enhance mechanical properties).
• Sustainability – The production of bricks does not require firing. This eliminates the need to build kilns and use fuel, which in the region often leads to deforestation and increases the risk of fires during the dry season, threatening both agriculture and residential areas. The loss of trees causes soil erosion, intensifies climate change effects, and results in long-term problems with crop yields.
• Educational value – The interlocking system makes masonry easier even for beginner masons and reduces errors. The construction process thus also serves as a practical training opportunity for the local community, which aligns with the socio-economic goals of our development project.

Masonry

This year we paid particular attention to the precision of masonry work. In previous years, we encountered difficulties with local workers being accustomed to using mortar joints 4 cm thick or more. This year, we agreed with them to maintain a joint thickness of 1 cm and made sure this was followed. As a result, the masonry phase took longer, but under our supervision and especially with guidance from masons Patrick and Charles, the careful workmanship was carried out consistently up to the bond beam.

A major challenge for our workers were the double external walls, as this practice is not common locally. We therefore had to be extra careful with maintaining proper bonding and staggered courses to avoid long vertical joints.

Structural solution

The load-bearing external walls were designed as double-layer masonry, supplemented along the length of the building with half-pilasters to increase the spatial rigidity of the structure.

Openings and ventilation

Window openings are concentrated in rooms with constant human presence – the operations office and the area designated for honey and wax extraction and processing. Storage spaces are equipped with ventilation ducts created by laying bricks "on edge." Thanks to the holes in the bricks, natural ventilation is enabled without weakening the wall. All openings (windows and ventilation ducts) are fitted with insect screens from the inside. These elements serve several functions:

• ensuring hygienic conditions during product processing,
• protecting workers from bees, which can become aggressive when handling honey,
• preventing mosquito entry and thus reducing the risk of malaria infection, especially during evening work in the rainy season.

Window openings are also fitted with metal frames with glass panes, ensuring durability, safety, and easy maintenance during the building's operation.

The building is not equipped with forced ventilation; natural ventilation is provided by ventilation ducts, openable windows, and threshold-free doors.