Across the world, numerous construction techniques have developed locally over hundreds of years to suit the specific climatic conditions and needs of the region. These construction techniques are typically sustainable and embody the spirit of vernacular architecture. One such construction methodology is wattle and daub, which is believed to have a history spanning thousands of years. Read on to discover what wattle and daub is and learn about the features, benefits and process of daub and wattle house construction.
What is Wattle and Daub?
Wattle and daub is a construction method, commonly for walls, using materials like wood, bamboo, reeds, clay and straw. With origins dating back to more than 6000 years ago, this method was ordinarily used to construct primitive huts in parts of North America, Africa, central Europe and South-East Asia. However, this process is still adopted to build modern structures, especially when eco-friendly house construction is a priority. Regional variations of wattle and daub construction include Jacal (southwestern USA), Pierrotage (France) and Pug and Pine (Australia).
Building a Wattle and Daub Home
Components of Wattle and Daub Construction
- Frame: The building framework typically consists of stone (or concrete in modern construction) foundations with wooden posts and beams. This framework is responsible for the transfer of structural loads.
- Wattle (Withies): Wattle refers to a woven lattice. This lattice is commonly made of bamboo, but other materials like reeds, straw, timber branches and twigs can also be used as alternatives.
- Daub (Infill Material): Clay is the most frequently used infill material in wattle and daub construction. Sometimes, additional elements like straw, cow dung, gravel, crushed chalk and sand are also added to enhance bonding.
- Reinforcements: Additional reinforcements like high density fiber, straw, glass bottles, crushed glass, gravel and lime are occasionally used to increase the strength of wattle and daub walls.
Wattle and Daub Construction Process
- Erection of Framework: First, the framework consisting of wooden structural members is erected. This framework is erected in the conventional post and beam form, but can also have additional members in diverse shapes to increase the strength and enhance aesthetics.
- Wattling: Lattices made of bamboo (or other similar materials) are woven around the wooden framework- this process is known as wattling. The lattice can take on different forms, such as a panel with layers of bamboo strips stacked over one another or interlaced like woven baskets. The type and density of the lattice depends on the structural requirements specific to each project.
- Daubing: This process involves pressing in the daub materials (lime, clay, cow dung, etc.) between the lattice panels on both sides. The daub filling is well compressed and then cured for a few days to obtain adequate strength.
- Finishing: The wattle and daub wall surface is treated after it dries and hardens (which takes 3-4 weeks) with materials like lime plaster or cow dung to ensure a smooth and even finish. This surface layer also protects the inner elements from degradation.
Image source: Link
Although the wattle and daub construction method is thousands of years old, it has inspired new building technologies like ferrocement, in which cement mortar is infilled between steel mesh panels and framework.
Why Opt for a Wattle and Daub House?
Wattle and daub construction offers the following benefits:
- Eco-friendly: The use of locally sourced and naturally available materials in wattle and daub architecture makes this method environmentally friendly. Reduced carbon emissions during the transport, manufacture and construction of such structures promotes sustainable building practices.
- Flexibility: A wattle and daub wall can take on complex organic forms such as hyperbolic and parabolic curves. This is possible because bamboo can be woven in curved forms as required,—unlike typical masonry walls—enabling increased design freedom and innovation.
- Thermal Insulation: Wattle and daub walls have good thermal insulation properties,—better than brick masonry walls—meaning that they can maintain comfortable internal temperatures even with varying external climatic conditions.
- Seismic Resistance: Since wood is the material commonly used for structural framing, wattle and daub structures generally have good earthquake resistance. The wooden joints are typically flexible and have the ability to undergo slight deflections that reduce the impact of tectonic waves during earthquakes.
- Cost Effective: When locally available materials are used in the construction of a daub house, the total project cost gets significantly reduced. However, the cost can increase if premium qualities or exotic varieties of wood and other materials need to be sourced from distant places.
Limitations of Wattle and Daub Construction
Despite its benefits, wattle and daub construction has its challenges, some of which are:
- Labour Requirement: Labour with adequate knowledge and skills regarding the wattle and daub construction method can be difficult to find. Training unskilled labourers can be an expensive undertaking.
- Wall Thickness: Although a wattle and daub wall can be constructed with a thickness as low as 2 inches, such a wall would not be very strong or durable. A typical wattle and daub wall is around 12 inches thick, which is much higher than conventional brick or cement block masonry walls.
- Shrinkage and Porosity: Even when well executed, shrinkage and cracks can often occur in wattle and daub walls. Thin daub layers also make the walls very porous, making the inner layers vulnerable to decay by moisture penetration.
- Modern Finishing: When modern materials like cement plaster are used to finish wattle and daub walls, gaps between junctions can form, leading to increased porosity.
- Maintenance and Repair: As long as the inner wattle layers are in good condition, the surface daub layers can be redone in case of any external damage. However, when the daub layers get degraded, wattle layers get easily degraded by fungi, pest attacks and weather changes. In this case, the entire wall requires replacement.
Constructing a Modern Wattle and Daub House
Although they have their limitations and challenges, the benefits of sustainable construction methods like wattle and daub far outweigh the cons. Moreover, the integration of modern construction technologies with ancient building knowledge—along with the efforts of architects and other building professionals—can lead to the evolution of a wattle and daub construction system which has overcome its limitations. With the looming threats of global warming and climate change, such methods must be promoted to ensure sustainable development and mitigate the negative impacts of the AEC (Architecture, Engineering and Construction) industry.
Hemali Patel