Building Technology 1 Reviewer PDF

SEMESTER 2 (P1) – BUILDING TECHNOLOGY 1 REVIEWER SCIENTIFIC BACKGROUND 2 TYPES OF WOOD Through Photosynthesis, 1. NATURAL WOOD GLUCOSE is converted into organic molecules A. Softwood that comprise the tree,...

SEMESTER 2 (P1) – BUILDING TECHNOLOGY 1 REVIEWER SCIENTIFIC BACKGROUND 2 TYPES OF WOOD Through Photosynthesis, 1. NATURAL WOOD GLUCOSE is converted into organic molecules A. Softwood that comprise the tree, Usually softer Almost always light CELLULOSE- forms the walls of wood cells Loose grain chemically cellulose is a polymer Lighter weight the reinforcement bars Higher sap “GYMNOSPERMS”- Do not bear flowers, LIGNIN- glue that binds the cells have a single main stem and most are evergreen, with leaves that are needlelike. hardened cement B. Hardwood Denser (PARTS OF A TREE) Usually darker in color BARK- outer layer Slower growth rate Heavier CAMBIUM- thin layer after the bark Compressive and tensile SAPWOOD (ALBURNUM)- the younger, softer, Strength living portion of wood between the cambium Close grain and heartwood “ANGIOSPERMS”- Generally flowering trees. Have broad leaves and are deciduous, HEARTWOOD (DURAMEN)- older, harder, shedding and regrowing leaves annually. inactive core of a tree, usually darker, denser, 2. ENGINEERED WOOD and more durable than the surrounding Composite Wood sapwood. Plywood GROWTH RINGS (ANNUAL RING) – produce Veeners during a single year’s growth of a temperate Laminates tree. Partcile board Mdf/hdf (ADVANTAGES OF WOOD) (DIFFERENCE BETWEEN) Lightweight FIRE RETARDANT - make combustible material difficult to ignite Renewable Natural Resistor FIRE RESISTANT- non-combustible creates a barrier against fire Sound Absorption Aesthetic (DISADVANTAGES OF WOOD) ANISOTROPHIC- Different value of wood product when measured in different directions. (When you Flammable cut the wood into 2, the left one and right one is Insect Damage different Size Irregularities WOOD, WHICH IS STRONGER ALONG THE GRAIN THAN ACROSS IT. AESOTROPHIC- when you cut it into the middle it has the same materials.  SEMESTER 2 (P1) – BUILDING TECHNOLOGY 1 REVIEWER (HARDWOOD) (SOFTWOOD) MAHOGANY (SWIETENIA MACROPHYLLA) PINE Native range: Mexico to southern Strong, shock resistant material suitable for Amazonia, Brazil. furniture dents show up in the wood just add Most widespread and only true to the aged look. commercially grown mahogany species. GMELINA (GMELINA ARBOREA) Comparison to Gmelina is a fast-growing tree introduced to the Mahogany grows slower but matures for Philippines, valued for its light, strong, and harvest in 15-20 years. termite-resistant wood. It’s commonly used in furniture, construction, and paper pulp Downside production. The tree can reach up to 30 Toxic leaves can kill native plant species meters in height and 50 cm in trunk diameter. under its canopy. PRODUCTION OF WOOD NARRA Conversion of logs into lumbers happens in Narra is the Philippines’ national tree. lumber mills, usually located close to forests, Premium hardwood for furniture and process consists of four basic steps: construction. 1. TRANSPORTATION OD LOGS FROM Used in carving and musical THE FOREST TO THE MILL instruments. 2. DEBARKING OF LOGS Considered vulnerable but highly valued. 3. SAWING THE DEBARKED LOGS INTO MOLAVE LUMBER 4. SURFACING LUMBER MEMBERS A valuable Philippine tree. SMOOTH Wood is hard, durable, and used for furniture, carvings, and construction. IN A MODERN MILL, THE SAWING HIGHLY Among the most expensive lumbers AUTOMATED AND IS TYPICALLY CONTROLLED BY ONE PERSON Ideal as an ornamental shade tree with violet flowers. – THE SAWYER YAKAL (SHOREA ASTYLOSA) Endemic to: Philippines (DIFF. TYPES OF SAWING) Size: 25–30 meters tall 1. FLAT SAWING (PLAIN SAWING) Wood: Hard, dark brownish-yellow Uses: Furniture, stairs, carvings In flat sawing (plain sawing), boards are cut such that growth rings can be parallel, Habitat: Primary forests at low altitudes diagonal, or perpendicular to the board’s in Luzon, Samar, Negros, and Mindanao surface, resulting in varied grain patterns. Traditional Use: Wood extractions have tumor-inhibiting properties  SEMESTER 2 (P1) – BUILDING TECHNOLOGY 1 REVIEWER 2. RADIAL SAWING (QUARTER SAWING) TYPES OF SEASONING Log is first converted into 4 pcs thru the center, KILN DRYING- is a process where wood growth rings are perpendicular to the wider is dried in a controlled chamber, faces. minimizing moisture content without causing defects. AIR DRYING- a method where lumber SEASONING is stacked outdoors on stickers, After sawing, lumber undergoes seasoning (a allowing natural air circulation to controlled drying process) to reduce its reduce moisture content by about 20%. moisture content to suitable levels for SOLAR DRYING- Uses solar energy as construction. Seasoning implies to the an alternative controlled rate of drying CHEMICAL DRYING- high value application, involves soaking lumber in Moisture content (MC) in a piece of wood is an anhydrous chemical for about a day the weight of water in wood divided by its oven to slow moisture loss, minimizing dry weight: internal stresses and reducing the risk of checking. FORMULA W/ SAMPLE SOLUTION MC= WEIGHT OF WATER IN WOOD/WEIGHT WOOD WEIGHT- 480-500 kg/cubic meter OF OVEN DRY WOOD X 100 6 KG-WOOD FIBER SATURATION POINT AFTER DRYING WOOD IS NOW 4.5 KG MC IS 30% 6KG - 4.5KG = 1.5KG (weight of water in wood) CELL WATER HAS JUST BEGUN TO EVAPORATE WEIGHT OF WATER IN WOOD/WEIGHT OF SWOLLEN STATE OVEN DRY WOOD x 100 IF MC IS AT 15% WOOD CAN BE 1.5KG/4.5 KG x 100 = 33% CONSIDERED STRUCTURAL GREEN LUMBER VS DRY/SEASONED LUMBER SURFACING LUMBER SIS- SURFACED ON 1 WIDE SIDE MOISTURE CONTENT IS LESS THAN S2S- SURFACED ON 2 WIDE SIDES 19%= DRY/SEASONED LUMBER S4S- SURFACED ON 4 SIDES MOSITURE CONTENT GREATER THAN S1S1E- SURFACED 1 SIDE, 1 EDGE 20%= GREEN LUMBER S2S1E- SURFACED 2 SIDES, 1 EDGE MC OF LESS THAN 19% IS NOT SUSCEPTIBLE TO FUNGAL DECAY “STRENGTH AND STIFFNESS OF LUMBER LUMBER CLASSIFICATIONS INCREASES AS THE MOISTURE CONTENT WOOD BOARDS- thickness less than 2 DECREASES” inches  SEMESTER 2 (P1) – BUILDING TECHNOLOGY 1 REVIEWER DIMENSION LUMBER- thickness 2-4 inches ENGINEERED WOOD MOST USED LUMBER 2X Engineered wood products for structural applications TIMBER- 5 inches or greater GLUELAM- means Glued and Laminated Dimension lumber glued together WOOD DEFECTS AND DEFORMATIONS KNOT- branch of tree emerges from the PLYWOOD- made of thin plies of wood glued trunk together WOOD CHECK - separation of wood fibers along the rays BLOCK BOARD- soft wood strips glued together as core - surface of wood dry faster than its interior WOOD VEENER- thin slices of wood glued to a WOOD SHAKE core - separation of wood fibers along the growth ring - occurs during the growth of the tree WOOD SPLIT - complete separation of wood members - occurs during the growth of the tree and aggracated during drying LAMINATE- thin sheet of a material used to WANE cover a core, usually involves plastics and composites - absence of wood or presence of bark on the corners PARTICLE BOARD (CHIP BOARD)- from wood chippings and shavings with resin as binder BOW, CROOK, CUP, TWIST MDF/HDF- medium/high density fiberboars; Breaking down wood residuals into wood fibers combined with resin then heat pressed. ORIENTED STRANDBOARD- wood shavings and then glued by bind resin then bind them together by heat