Bamboo construction, Ferrocement, Wattle & Daub technique

A presentation on the constrcution techniques by Bamboo construction, Ferrocement, Wattle & Daub techniques, their applications and advantages disadvantages and site images

1. Ferrocement, Bamboo and Wattle & Daub Techniques Presented by – Azleen F. Kazi FO. Y. B. Arch SE&CM’s COA, JALGAON

2. Ferrocement What is Ferrocement ? Ferro Cement (also called Ferro-concrete) is a rich or composite mortar plaster applied to both sides of a thin and well distributed reinforcement layer (usually a layer metal mesh and closely spaced thin steel rods). Normally plaster of 1:2 cement mortar should be applied to a matrix structure made of weld mesh would round the chicken mesh. Ferro cement componets have high strength as the cement content is very high ( i.e , in the orders of 700 kg/m3). Since the steel is spread over the area, the ferro cement components are usually a homegenious in composition. Ferro cement is applied with pressure over the weld chicken mesh matrix. The mortar holds in position because of the mechanical interlocking. So No shuttering is required to cast ferrocement components. Since Ferrocements are made of mortar with higher cement content, the chances of shrinkage cracks are high. Ferrocement components are to be cured for a minimum period of 7 days without interruption to avoid any shrinkage cracks. Typical Cross section of ferrocement Dome construted out of ferrocement

3. Applications of Ferrocement . Advantages: Raw materials required for Ferrocement construction are easily available The fabrication of the mesh can be done in many shapes that suits the requirements Ferrocements are more durable and are cheaper than steel and wood Application of Ferro-cement doesn’t require any heavy machinery Disadvantages: Excessive shrinkage due to higher cement content. Needs constant curing for a period of 7 days to avoid any shrinkage cracks Prone to corrosion of MS rods and GI mesh due to incomplete coverge of materials by mortar Ferro-cement is labour intensive. So it might not be economical to use ferrocements in places where the labour costs are high As ferro-cement components are usually thin structures, Buckling is another factor that needs to be taken into consideration during Used in making boats Used as planks for shelves in housing projects replacing costly wooden planks Used in construction of boxes for water and electrical meters Used in construction of sewage manhole covers Ferro-cement components are Used in Rural areas for low cost housing Recently Ferro-cements are used in some residential and industrial buildings also Ferrocement Typical Cross section of ferrocement Ferrocement Construction

4. Construction Methods Armature System :   The armature system is a framework of tied reinforcing bars (skeletal steel) to which layers of reinforcing mesh are attached on each side. Mortar is then applied from one side and forced through the mesh layers towards the other side, as shown in Fig 12.5.1. The skeletal steel can assume any shape. Diameter of the steel bars depends on the size of the structure. Skeletal steel shall be cut to specified lengths, bent to the proper profile, and tied in proper sequence. Sufficient embedment lengths shall be provided to ensure continuity. For bar sizes 6 mm or less, lap lengths from 230 to 300 mm may be sufficient. The required number of layers of mesh shall be tied to each side of the skeletal steel frame. 12.5.2.2 Closed‐ mould System :    The mortar is applied from one side through several layers of mesh or mesh and rod combinations that have been stapled or otherwise held in position against the surface of a closed mould , i.e. a male mould or a female mould . The mould may remain as a permanent part of the finished ferrocement structure. If removed, treatment with release agents may be needed. The use of the closed mould system represented in Fig 12.5.2 tends to eliminate the use of rods or bars, thus permitting an essentially all mesh reinforcement. It requires that plastering be done from one side only.   12.5.2.3

5. Construction Methods Integral‐ mould System :   An integral mould is first constructed by application of mortar from one or two sides onto a semi‐rigid framework made with a minimum number of mesh layers. This forms, after mortar setting, a rigid but low quality ferrocement mould onto which further layer of reinforcing mesh and mortar shall be applied on both sides. Alternatively, the integral mould may be formed using rigid insulation materials, such as polystyrene or polyurethane, as the core. A schematic description of this system is given in Fig 12.5.3. 12.5.2.4 Open‐ mould System :   In the open‐ mould system, mortar is applied from one side through layers of mesh or mesh and rods attached to an open mould made of a lattice of wood strips. The form, shown in Fig 12.5.4, is coated with a release agent or entirely covered with polyethylene sheeting (thereby forming a closed but nonrigid and transparent mould ) to facilitate mould removal and to permit observation and/or repair during the mortar application process. This system is similar to the closed‐ mould system in which the mortar is applied from one side, at least until the mould can be removed. It enables at least part of the underside of the mould to be viewed and repaired, where necessary, to ensure complete and thorough impregnation of the mesh.

6. Some important uses of ferrocement are as follows: Ferro cement planks & panels can be used for construction of beams, columns, floor, roofs, walls, chajjas and lintels. It can be used in combination with plain cement concrete or reinforced cement concrete. Ferro cement being a thin material single piece panel of size up to 4.5m x 4.5m or more can be manufactures as floors and walls. Large span beams, roofs can also be constructed. Ferro cement being crack resistant and anticorrosive material lasts much more than R.C.C. Quantity requirement of ferrocement in building construction is much less as compared to R.C.C. Therefore dead load of ferrocement building is reduced by at least 50%. Consequently the foundation cost gets reduced. Ferro cement membrane lining is used for water proofing of terraces, basements, tanks. Ferro cement water proofing is the only treatment where reinforcement is used in the form of wire mesh layers and vibrations are provided in the matrix layers. Therefore ferrocement water proofing treatment should generally last longer than conventional. 9 Ferro cement anticorrosive protective lining for rehabilitation is far better the gunting . In the case of Gunting there is generally one layer of weld wire mesh with wires at 3" to 6" spacing and the dia. of wires is form 1.5mm to 2.5mm. In the case of ferrocement galvanised wire mesh layers with small dia. wires 18 swg to 20 swg , spacing about 12mm center to center are used. Therefore unreinforcement and consequently least possibility of crack formation. Ferro cement is a good material for elevation treatment. Since it is constructed in these sections, it contributes negligible dead weight, and at the same time it is crack resistant, water proof and strong. Ferro cement is a very good fire resistant material having capacity to resist fire up to 750°C for long period of 48 hours and even more. Ferro cement can be modified to resist even high temperatures, say 1200°C to 1500°C. Ferro cement buildings are better pollution and fire resistant as compared to RCC. Therefore, ferrocement buildings are preferable to RCC for functional VIP and strategic buildings.

7. Case study : Shell Retrofit The DesignBuilder energy model, including floorplan zones, is shown in Figure. The wall and roof ferrocement composite is variable XPS rigid insulation and 75 mm of outside concrete. The ground floor is a covered but uninsulated 100 mm concrete slab with a U-value of 0.350 W/m2 -K. The original slab is not replaced for the retrofit. It’s assumed that the retrofit has only had the HVAC and DHW components upgraded to heat pumps. The conditioned floor area is 128 m2 . Prior to the retrofit, the walls are assumed to be wooden studs with plywood sheathing and fiberglass insulation, for a U-value of 0.432 W/m2 -K. The roof is also wooden studs, plywood and asphalt shingles for a U-value of 0.254 W/m2 -K. Windows are double-pane with a Uvalue of 2.71 W/m2 -K. The existing building is left intact after placing the ferrocement shell, 50 energy model which means that less XPS needs to be added. Thermal bridging of the soft wooden studs and fiberglass batt insulation is not directly supported by EnergyPlus . In this case, bridging is ignored because it would only increase the effective U-value by less than 10%. The retrofit baseline also includes lighting and appliance upgrades that reduce electricity use and heat gains.

8. A combination of ferrocement and bamboo wall construction

9. BAMBOO

10. Historic use of bamboo for construction In its natural form, bamboo as a construction material is traditionally associated with the cultures of South Asia, East Asia, the South Pacific, Central and South America. In China and India, bamboo was used to hold up simple suspension bridges, either by making cables of split bamboo or twisting whole culms of sufficiently pliable bamboo together. One such bridge in the area of Qian-Xian is referenced in writings dating back to 960 AD and may have stood since as far back as the third century BC, due largely to continuous maintenance. Bamboo has also long been used as scaffolding; the practice has been banned in China for buildings over six stories, but is still in continuous use for skyscrapers in Hong Kong. In the Philippines, the nipa hut is a fairly typical example of the most basic sort of housing where bamboo is used; the walls are split and woven bamboo, and bamboo slats and poles may be used as its support. In Japanese architecture, bamboo is used primarily as a supplemental and/or decorative element in buildings such as fencing, fountains, grates and gutters, largely due to the ready abundance of quality timber. In parts of India, bamboo is used for drying clothes indoors, both as a rod high up near the ceiling to hang clothes on, and as a stick wielded with acquired expert skill to hoist, spread, and to take down the clothes when dry. It is also commonly used to make ladders, which apart from their normal function, are also used for carrying bodies in funerals. In Maharashtra, the bamboo groves and forests are called Veluvana , the name  velu  for bamboo is most likely from Sanskrit, while  vana  means forest. Furthermore, bamboo is also used to create flagpoles for saffron- coloured , Hindu religious flags, which can be seen fluttering across India, especially in Bihar and Uttar Pradesh. In Central and South America, bamboo has formed an essential part of the construction culture. Vernacular forms of housing such as bahareque have developed that use bamboo in highly seismic areas. When well-maintained and in good condition, these have been found to perform surprisingly well in earthquakes. Bamboo scaffolding can reach great heights.

11. Modern use of bamboo round poles for construction Over the past few decades, there has been a growing interest in using bamboo round poles for construction, primarily because of its sustainability. Famous bamboo architects and builders include Simón Velez, Marcelo Villegas, Oscar Hidalgo-López, Jörg Stamm , Vo Trong Nghia , Elora Hardy and John Hardy. To date, the most high profile bamboo construction projects have tended to be in Vietnam, Bali (Indonesia), China and Colombia. The greatest advancements in structural use of bamboo have been in Colombia, where Universities have been conducting significant research into element and joint design and large high profile buildings and bridges have been constructed. In Brazil, bamboo have been studied for more than 40 years at the Pontifical Catholic University of Rio de Janeiro PUC-Rio for structural applications. Some important results are: the bamboo bicycles, the bamboo space structure with rigid steel joints, the deployable bamboo structure pavilions and the active bending bamboo amphitheater structure with flexible joints Bamboo Transcends

12. Modern use of laminated bamboo for construction Bamboo can be cut and laminated into sheets and planks. This process involves cutting stalks into thin strips, planing them flat, and drying the strips; they are then glued, pressed and finished. Long used in China and Japan, entrepreneurs started developing and selling laminated bamboo flooring in the West during the mid-1990s; products made from bamboo laminate, including flooring, cabinetry, furniture and even decorations, are currently surging in popularity, transitioning from the boutique market to mainstream providers such as Home Depot. The bamboo goods industry (which also includes small goods, fabric, etc.) is expected to be worth $25 billion by 2012.  The quality of bamboo laminate varies among manufacturers and varies according to the maturity of the plant from which it was harvested (six years being considered the optimum). Taichung World Flora Expo

13. Case Study Bamboo was used for the structural members of the India pavilion at Expo 2010 in Shangha i. The pavilion is the world’s largest bamboo dome, about 34 m (112 ft) in diameter, with bamboo beams/members overlaid with a ferro-concrete slab, waterproofing, copper plate, solar PV panels, a small windmill, and live plants. A total of 30 km (19 mi) of bamboo was used. The dome is supported on 18-m-long steel piles and a series of steel ring beams. The bamboo was treated with borax and boric acid as a fire retardant and insecticide and bent in the required shape. The bamboo sections were joined with reinforcement bars and concrete mortar to achieve the necessary lengths. Bamboo has been used successfully for housing in Costa Rica, Ecuador, El Salvador, Colombia, Mexico, Nepal and the Philippines. An appropriate way of using bamboo for housing is considered to be "bahareque encemendato ", or "improved bahareque"/"engineered bahareque". This method takes the Latin America vernacular construction system bahareque (a derivative of wattle and daub and engineers it, making it considerably more durable and resistant to earthquakes and typhoons.

14. Kontum Indochine Cafe by Vo Trong Nghia Architects

15. Kontum Indochine Cafe by Vo Trong Nghia Architects Fifteen conical bamboo columns support the roof of this waterside cafe designed by Vo Trong Nghia Architects at a hotel in central Vietnam. Referencing the shapes of typical Vietnamese fishing baskets, the top-heavy bamboo structures form a grid between the tables of the open-air dining room, which functions as the restaurant and banqueting hall for the  Kontum Indochine Hotel. Vo Throng nghia Architects designed the restaurant without any walls, allowing uninterrupted views across the surrounding shallow pools of water, and beyond that towards the  neighbouring river and distant mountains. The roof of the structure is clad with bamboo but also contains layers of thatch and fibre -reinforced plastic. In some places the plastic panels are exposed, allowing natural light to permeate the canopy.

16. There's no air conditioning, but the architects explain that the surrounding waters and the shade of the overhanging roof help to keep the space cool, even in the hottest seasons. "By providing shadow under the bamboo roof and maximising the cool air flow across the water surface of the lake, the open-air indoor space successfully operates without using air conditioning," they say. All of the fixings for the columns are made from bamboo rather than steel and were constructed using traditional techniques, such as smoke-drying and the use of bamboo nails. "The challenge of the project is to respect the nature of bamboo as a material and to create a distinctive space unique to bamboo," say the architects. "The bamboo columns create an inner lining, giving the impression of being in a bamboo forest.“ Bridges cross the water to provide access to the cafe from three sides, plus a concrete and stone kitchen is positioned at the back. Kontum Indochine Cafe by Vo Trong Nghia Architects

17. WATTLE AND DAUB WALLS

18. INTRODUCTION A Wattle is a woven lattice of willow or hazel striplings (young, thin branches). Daub is a sticky mixture of subsoil, day and straw, sand or animal hair, very similar to cob. Wattle and daub  is a composite building method used for making walls and buildings, in which a woven lattice of wooden strips called  wattle  is  daubed  with a sticky material usually made of some combination of wet soil, clay, sand, animal dung and straw. Wattle and daub has been used for at least 6,000 years and is still an important construction method in many parts of the world. Many historic buildings include wattle and daub construction, and the technique is becoming popular again in more developed areas as a low-impact sustainable building technique. Wattle and daub in wooden frames.

19. HISTORY The wattle and daub technique was used already in the Neolithic period. It was common for houses of a Linear pottery and  Rössen  cultures of Central Europe, but is also found in Western Asia ( Çatalhöyük ,  Shillourokambos ) as well as in North America (Mississippian culture) and South America (Brazil). In Africa it is common in the architecture of traditional houses such as those of the Ashanti people. Its usage dates back at least 6000 years. There are suggestions that construction techniques such as lath and plaster and even cob may have evolved from wattle and daub. Fragments from prehistoric wattle and daub buildings have been found in Africa, Europe, Mesoamerica and North America. A review of English architecture especially reveals that the sophistication of this craft is dependent on the various styles of timber frame housing. A wattle and daub house as used by Native Americans during the Mississippian period

20. Styles of infill panels  There were two popular choices for wattle and daub infill paneling: Close-studded paneling Square paneling 1 . Close-studding Close-studding panels create a much more narrow space between the timbers: anywhere from 7 to 16 inches (18 to 40 cm). For this style of panel, weaving is too difficult, so the wattles run horizontally and are known as ledgers. The ledgers are sprung into each upright timber (stud) through a system of augered holes on one side and short chiseled grooves along the other. The holes (along with holes of square paneling) are drilled at a slight angle towards the outer face of each stud. This allows room for upright hazels to be tied to ledgers from the inside of the building. The horizontal ledgers are placed every two to three feet (0.6 to 0.9 metres ) with whole hazel rods positioned upright top to bottom and lashed to the ledgers. These hazel rods are generally tied a finger widths apart with 6–8 rods each with a 16-inch (40 cm) width. Gaps allow key formation for drying. A woven wattle gate keeps animals out of the 15th century cabbage patch ( Tacuinum Sanitatis , Rouen)

21. 2. SQUARE PANELS Square panels are large, wide panels typical of some later timber frame houses. These panels may be square in shape, or sometimes triangular to accommodate arched or decorative bracing. This style does require wattles to be woven for better support of the daub. To insert wattles in a square panel several steps are required. First, a series of evenly spaced holes are drilled along the middle of the inner face of each upper timber. Next, a continuous groove is cut along the middle of each inner face of the lower timber in each panel. Vertical slender timbers, known as staves, are then inserted and these hold the whole panel within the timber frame. The staves are positioned into the holes and then sprung into the grooves. They must be placed with sufficient gaps to weave the flexible horizontal wattles. Wattle panel

22. Advantages of wattle daub walls Simple construction Made of naturally occurring, abundant materials. Highly durable if properly constructed concerning it's structure, but also considering climate and location. Historically proven method. Failure possibilities and causes are well-known. Highly sustainable Villages/houses could be constructed with help from community members/families. If properly designed regarding orientation and ventilation, the high thermal mass of these buildings could be used as an advantage. Strategies vary depending on climate. Proper design, planning and construction can make maintenance costs irrele Wattle and daub construction in the Dominican Republic. Disadvantages of wattle daub walls Most problems arise from improper design and construction, and these disadvantages can be dramatically decreased with good planning. Other disadvantages are relative. Although construction and design are relatively simple, they can be quite labor-intensive, especially the assembling of the wattle panels. Drying of the daub can take a long time, depending on climate and humidity, although good planning usually resolves this problem. Little information available on the installation of regulated fittings, such as electricity and plumbing elements. Likewise, the installation of standardized fittings such as pre-made windows and doors could be a problem, since most are designed to fit into a frame of specific dimensions, usually made of cement.(More applicable to developed countries or cities.) It is highly recommended to limit the contact of the walls with water to a minimum, mostly through the foundations and roof.

23. Construction The key components in creating a wattle and daub building are the frame, the wattle panel, and daub . The Frame The first step in creating a building using wattle and daub is the creation of the frame. The frame should provide the correct detailing necessary to accept and hold the staves of the wattle panel. Two of the most common frameworks are close studding and parallel bracing. Close studding creates narrow spacing between the timbers and allows for support of the wattle. Parallel bracing uses diagonal bracing to offer support to the wattle. Materials Wood Wood is an abundant renewable resource provided that it is used rationally. Wood is also physically and mechanically resistant. Wood should be cut when the sap contents is at its lowest and during the dry season. The reason for cutting wood during this time is that it reduces the possibility of attacks by insects. After cutting the wood it should be left out to dry. Drying the wood improves the structural integrity and helps with humidity control. Wood should also be preserved in order to repel biological and environmental elements The frame of a structure before applying wattle and daub.

24. Cane/Bamboo Like wood, Cane/Bamboo is an abundant renewable resource. It is also easy to manually work with. Cane/Bamboo must be cut at adult age and during the dry season. Adult age will depend on the species used. Drying is needed to avoid cracks and dimensional changes (shrinking) during construction. Preservation of this material is great due to the space between the fibers. Soaking the poles in a salt, lime, or asphalt solution can greatly reduce the negative effects of biological and environmental elements. Wattle Panels The wattle panel consists of two main components; staves and withies (small malleable twigs or bamboo battens). Staves are used to help support the wattle panels. It’s important that the staves are not too thick. If the staves are too thick then it will be hard to work the withies around them and increases the possibility of breaking the withies. The withies are woven around the staves to form a basket like design. The withies should enter in alternate directions to make them self-anchoring, further strengthening and supporting the wattle panel. Once the wattle panels are constructed the daub can be applied. Construction A mud and stud wall in Tumby Woodside, Lincolnshire Example of  pierrotage  construction in Ste Geneviève, Missouri.

25. Daub The word, daub, is derived from the old French term dauber, which means to plaster. Daub is primarily composed of earthen materials such as silt, sand, clay, and dirt. Earth can be a good building material due to its plasticity and compactability . However, earth does also have cohesive qualities which can be troublesome in humid regions and regions with great seasonal variations. Earth with large amounts of clay has higher cohesive qualities. To reduce cohesion, straw and sand can be added. Plastering The frame and wattle panels should be dusted before applying daub to the walls. Moreover the wall should be dry. These steps will help to insure that the daub will adhere to the panels. The next step is to plaster an underlay. The purpose of the underlay is to help level out the walls imperfections for the finishing layer. After the underlay is plastered, incisions should be made along the wall using wire brush or nails. The incisions will help increase the adhesion of the second layer. Once the underlay has dried, apply the final finishing layer to the wall. The second layer should consist of more sandy earth to help reduce cohesion of the daub. Finally, paint on a solution of chalk or lime to create a seal. The seal will further protect the walls from biological and environmental elements. Construction The durability of wattle and daub is illustrated by this wall, still standing after fire burnt the roof off. A wattle and daub panel in need of repair