Timber is widely used as a structural material in residential house construction. Among them, the roof is the most crucial part of a house that covers the interior of a building. The Western Province has the highest number of residential houses in Sri Lanka. Approximately 22,414 homes are built in the Western Province within a year, and various roof designs can be identified under different complexity categories. This study aimed to identify and categorize major roof types in Western Province houses based on their design complexity. For this study, 30 house plans were collected fromColombo, Kaluthara, and Gampaha districts (a total of 90 house plans) from the house owners, architects, and draftsmen as softcopies and hard copies. Collected 90 house plans were visually analyzed to identify their basic roof types. Then the roof design complexity was analyzed based on the number of basic roof types presented in each house plan. Five basic roof types (Gable roof, Hip roof, One side hip roof, Lean-on roof or Shed roof, and Pyramid roof) and 23 roof designs were identified in the Western Province houses of Sri Lanka. 75.5% of selected house plans had a Gable roof as the primary roof type. The simple-level roof design was the most abundant in Kaluthara andGampaha districts with 40% and 43.33%, respectively. However, moderate-level complexity roof design was the most abundant type in the Colombo District with 46.66%. Only 3.33% of complex level roofs were found in the Kaluthara District, while Gampaha and Colombo districts had 6.66%and 10% complex roofs. As per the final result the complexity of roofs increases from Kaluthara, Gampaha, and Colombo districts, which may be attributed to the economic levels of house owners.Out of the 90 house plans in the Western Province houses, 38% of roof designs had the simple-level of complexity. 34%, 21%, and 7% of house roofs had moderate, very simple, and complex-level categories, respectively. Roof design directly relates to the house owner’s perception. However, roofdesigners can recommend simple roof designs for their clients to enhance the structural accuracy and the cost-effectiveness of a residential house roof. Keywords: Roof design, Complexity, House plans, Western province

Building material with a thousand-year history which is only being second for stone can be introduced as wood. Complexity of wood is found in the interrelationship between several cells at a much larger scale. Wood cell wall is made up of cellulose, hemicellulose and the hydroxyl groups on these chemicals make the cell wall hygroscopic. Lignin is the agent cementing cells together while rigidifying the cell wall. It creates a comparatively hydrophobic molecule. Moisture in wood has a resilient effect towards its properties, and wood-water relations greatly affects on the wood in application. The aim of the study is to investigate the impact of hydroscopic property of historical timber against load bearing in heritage structures in Sri Lanka. Ambalam(s); heritage structure, a way side resting place built under vernacular architecture was selected as the case study. Padivitiya Ambalama, Panavitiya Ambalama, Karagahagedra Ambalama, Giruwa Ambalama and Rukula Ambalama were selected as in prior to timber as the main constructive material. This paper reviews on wood-water interaction through mapping the grain orientation of exposed cross sections of the structural components. The capability of water to alter physical properties of wood are only deliberated in cases wherever there is an influence on state and in transition. Results depicted the historical structural components have overcome the impacts caused due to the hydroscopic property through proper grain oriented sectional applications. This had influenced the structure to rest stable against load bearing for years.Keywords: Timber; Grain distribution; Hydroscopic property, Fibre saturation pointWood Science, Wood and Non-Wood Industry71Proceedings of the 25th International Forestry and Environment Symposium 2020 of the Department of Forestry andEnvironmental Science, University of Sri Jayewardenepura, Sri Lanka(87)

Moratuwa is traditionally famous for the carpentry and furniture manufacturing. There are several types of wood working industries in the cluster. Among them carpentry shops, sawmills and integrated sawmills were identified as the wood waste generating industries. Main objective of the study is to identify the current wood waste utilisation patterns and optimising the wood waste flow. Questionnaire surveys were conducted and field measurements were taken to gather reliable data. Stratified sampling method was followed. The prominent species use in the wood working industry is Teak (38.7%) followed by species are Mahogany (28.8%) and Albizia (3.1%). Machinery usage varies among different industries. Integrated sawmilling industry has the highest diversity of the machinery usage. Circular saw (44.6%) is the most abundant type of machinery used by integrated sawmilling industry. In carpentry industry planer saw (41.0%) is the most frequently using mechanical tool. Sawmilling industry uses different types of saws but the prominent type of sawing equipment is the circular saw (73.0%). 6,489.879 MT of total wood waste is generated within a month by entire population of wood working industries in Moratuwa. Out of them, sawmills produce 4,279.750 MT/month of wood waste, 2,003,467 MT/month of waste by the integrated sawmills and carpentry shops produce 206,662 kg/month. Among the total wood waste generation saw dust contributes 76.5%, 16.5% of wanes and 6.9% of offcuts. It was found that 63.4% carpentry shops, 100.0% of sawmills and 91.0% of integrated saw mills already utilise their wood waste. Quantity of current overall wood waste utilisation within the area of 20 km radius is calculated as 2,903,625 kg/month which has a possible increment up to 4,198,319 kg only by improving the current wood waste transportation. Wood waste generation and utilisation flow diagram and shortest path among the utilisers and waste collection points were illustrated. By adopting this waste utilisation methods, several business opportunities can be created and waste can be utilised in environmental friendly manner.Keywords: Sawdust, Wood waste, Utilisation

The Moratuwa Woodworking Industry Cluster (MWIC) is a geographically concentrated cluster of over 1,600 small-to-medium scale wood-based manufacturing and retail facilities in Sri Lanka. Firms include furniture manufacturers, carpentry shops, sawmills, and integrated sawmills in Sri Lanka. The concept of industrial symbiosis was used to explore potential synergies and scale economies between cluster firms to share inputs such as energy and water, and currently common by-products, and waste to achieve higher efficiency in resource utilization. In this study, a survey of 180 primary and secondary wood product manufacturers was undertaken to quantify MWIC firm by-product production and consumption of wood residues to establish a baseline for possible end-use and waste synergies. The total population of enterprises generating wood waste is 730; retail facilities are not included. Sawmills produce approximately 66% of the 6,490 MT of MWIC’s monthly wood residue generation, with the balance produced by carpentry and integrated enterprises. Teak (Tectona grandis) and Mahogany (Swietenia macrophylla) are the dominant species used in the MWIC, accounting for most of the wood waste. The survey identified three main types of wood waste: sawdust (76.5%), boards with significant wane (16.5%) unusable for further products, and offcuts (6.9%). Sawdust accounted for 77% of wood waste generated within the study area. Only 55% of the wood waste generated in MWIC is currently utilized; the remaining 45% is taken to landfills or disposed in other ways such as simply disposed in waterways or non-approved locations. Improved wood waste sorting by type at the mill level and aggregated within the MWIC was determined to substantially increase the usability of wood waste as potential inputs in other wood manufacturing sectors in the MWIC.

The aim of the study is to identify the wood utilized in the traditional houses built in Uva province of Sri Lanka, constructed using traditional construction technologies. The timber samples were taken out from roof elements such as rafters, wall plates and reapers from three different timber structures located at three different locations constructed during 1960 - 1970 using vernacular timber preservation technics and preservatives. Samples were extracted and adequately prepared for a microscopic investigation to observe the characteristic microscopic anatomical features. Sledge microtome was used for wood sectioning and photomicrographs were obtained by polarized light microscope. The authentic samples and reference microscopic identification keys were employed in order to conclude on the wood species involved. The relative density of the samples was also measured using the maximum moisture content method to verify the identification. Timber samples were identified using vessels, fibers, rays, parenchyma, and other microscopic features. Based on the macro and micro examination of the external and microanatomical features the timber used for rafters, reapers, wall plates were identified as Mango wood which is scientifically known as Mangifera indica. The relative density values were in the range of 0.52 - 0.7

Upgrading Wood Based Industries in Sri Lanka with special reference to Moratuwa Furniture Cluster   H S Amarasekera Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Sri Lanka   The wood-based industry is one of the oldest industries in the country that provides livelihood to many people in both rural and urban areas. However, the industry has been in a state of deterioration in terms of quality and competitiveness due to inadequate wood supply in term of quality and quantity, unfavorable business climate, scarcity of trained manpower, lack of market opportunities, research support and finances for investments to improve the industry. There are around 1700 industries in Moratuwa wood based furniture cluster and it has been in existence for many decades. This industry has deteriorated over the years and is currently incapable of producing furniture of high quality for the export market.  However large firms in the cluster use advanced technology and have a totally integrated production process with saw mills, timber seasoning and treatment facilities indicating that it is an organized cluster that can be upgraded to an innovative cluster by implementing a comprehensive development program. There have been several initiatives on development of wood working industry and timber utilization research on timber processing have yielded data towards upscaling and redefining the small timber manufactures in Sri Lanka.  The key options that can be adopted to improve the industry are to improve utilization of available sustainable timber resources to increase the supply of raw materials to the Moratuwa cluster, improve product quality, increase marketability of products and minimize environmental pollution. Selected industries in this cluster can be upgraded into international standards by introduction of new technology and transfer of knowledge, providing systematic training in improving furniture designing, timber preservation, seasoning and machine maintaining capabilities.   Achievement of productive wood products industry will make a significant contribution towards employment generation and increasing the percentage of contribution to GDP by Timber based products. Keywords – wood industry, furniture, forestry, timber, development plan https://www.dropbox.com/s/kysnyqk8vbr4q7t/Amarasekera%20Moratuwa%20wood%20working%20industry%20SMAR%20conference%20abstract.pdf?dl=0  https://www.slideshare.net/studentlanka/upgrading-wood-based-industries-in-sri-lanka-with-special-reference-to-moratuwa-furniture-cluster

Structural timber can be identified as a construction material which has high strength to weight ratio, therefore can be used for structural members with larger spans. Timber is used for construction of roofs, doors, windows and ceilings and for house construction. In order to construct a typical single story house of 100 m2, a volume of approximately 1.5 m3 timber is used for roofing. About 320,000 houses are built in a year locally which require more than 470,000 m3 volume of timber. This is approximately 110,000 trees are harvested per year. Timber is the most common structural material used for roof construction in Sri Lanka, especially in residential house construction, and Coconut and Kempas are the most common timber types used. In order to investigate the timber usage in residential houses’ roof construction in Sri Lanka, ten residential houses roofed with timber were selected in Colombo area and the timber element sizes of those houses were investigated. The structural members of the roofs such as rafters, purlins, ridges and wall plates of each of these houses were designed against bending, deflection, bulking, shear and bearing. These were designed in accordance with according to the timber design guideline BS 5268-2:2002 (British Standard, 2002) to meet the relevant loading conditions. The results were compared with the actual member sizes used in each house. The typical sections used for rafters, ridge plates, wall plates and purlins are 4”×2”, 7”×2”, 4”×3”, 4”×2” respectively. It was found that the timber in 60% of Coconut rafters, in 80% of Kempus ridges and wall plates and in 55% of Kempus purlins was overused. Such timber wastage can be minimized by designing the roof members according to the design guidelines. This can save a large amount of timber thereby saving trees and environment. Show full item record

Timber is one of the major construction material in Sri Lanka and timber seasoning is a common practice for achieving dimensional stability. The industry uses timber for interior and exterior joinery work such as doors, windows, door and window frames and panelling. However, forming seasoning defects is a common issue which prevalent in this industry. Therefore this study is conducted to identify defects caused by seasoning for teak timber and to find out solutions. For this reason, there different kilns located in Biyagama, Horana and Kottawa, operated under different schedules were selected. The impacts of three schedules were tested using teak planks. Kiln temperature and moisture content were measured for the entire seasoning period. Cupping, twisting and end cracking were measured as defects. Moreover, prong test was also conducted to determine the stress condition of the dried wood samples. Among the selected kilns, only one was maintained under the operating parameters recommended by the kiln manufacturer. The results revealed that the kiln which was programmed to regulate temperature produced the least amount of defects. However, moisture content was not programed for any of the kilns. Therefore it can be concluded that temperature has more impacted on causing defects on timber drying in the seasoning period. Therefore it is essential to regulate the temperature as per with kiln schedule. Keywords: Construction industry, Timber identification, Seasoning issues, Kiln drying

In recent years, due to rising raw material and labor costs, increasing attention is being devoted to improve wood sawing practices. While a high cutting rate is still among the most desired characteristics, other factors such as improved cutting accuracy and surface quality, reduced kerf losses, noise, downtime, and maintenance of the machine are becoming increasingly important. However, band sawmilling have advantages over circular saws which include higher cutting speeds lower kerf waste, and typically lower noise levels. Considering above advantages several Sri Lankan companies have now established band saw milling factories. Thus the key objectives of this study were to evaluate cutting time of band sawmills and to investigate waste generation. Three different band saws (TRAK-MET TTP 600 premium; TM, Wood-Mizer LT20; WM, and Veheran; V) which are commonly used in Sri Lanka were used to this study. Evaluation of cutting time and waste generation in different band sawmills were done with special reference to Teak timber. Results show that the fastest cutting time in WM (mean cutting time of 27s), medium cutting time in TM (mean cutting time of 60s) and the slowest cutting time in Veheran (mean cutting time of 180s). The factors such as tooth profile, setting value, sharpening frequency, status of lubrication, tensioning pressure of the blade and capacity and the condition of the machine may have affected to the fastest cutting time. According to the results of evaluation of saw dust Veheran showed the highest wastage owing to high kerf and factors such as poor lubrication, lower tensioning pressure. Moreover, cutting time negatively correlated with the lubrication and saw tension in band sawmills. Therefore, it can be concluded that proper saw mill management is necessary for reduction of timber wastage and increase the efficiency of the industry.

A large scale solid wood flooring factory is to be established in Sri Lanka. On the planning stage of this industry it was found that information on wood properties of local timbers such as Hevea brasiliensis for wood flooring are not available. Hence, the present study has been conducted to gather data on selected wood properties of Rubber wood and how the wood quality changes with growth rate of trees.Hevea brasiliensis 35 year old trees were selected from three size classes: suppressed, co-dominant and dominant. Sample disks were removed at top (80%), middle (50%) and breast height of the log length. Radial variations were also studied at percentage distances from pith to bark.Wood quality was assessed by ring specific gravity. Ring width remained more or less constant from pith towards bark with slight decrease towards the bark indicating the uniform growth rate. However no specific variation was observed in ring specific gravity. This radial variation of growth rate and specific gravity was similar in all three size classes. Application of Rubber wood as solid wood elements for flooring was experimentally assessed by hardness to loads applied to the wood and specific gravity. The mean specific gravity of suppressed, co-dominant and dominant trees were 0.564, 0.629 and 0.631 respectively indicating that the specific gravity of Rubber wood lies within the required standard for flooring which is 0.5-0.75. In the hardness test, it was observed that all three size classes generally show a gradual increase in hardness from pith towards bark. The values of average hardness of suppressed, co dominant and dominant trees were 341 kgf, 405 kgf and 433 kgf, hence co dominant and dominant trees have hardness values above 400 kgf, the standard value for wood flooring. These results indicate that Hevea brasiliensis has wood properties which are within European standard and Indian standard for manufacture of wooden flooring.