BTECH 1: Construction Materials - Wood and Stones Quiz

Wood

• Wood is a fibrous substance that composes the trunk and branches of a tree, lying between the pith and the bark.
• Xylem is the technical term for wood, while lumber refers to processed wood used as a building material.
• Timber refers to wood from trees that are yet to be processed.

Components of Wood

• Pith: the very center of the wood, the oldest part of the tree.
• Sapwood: the soft outer layer of the wood.
• Bark: the outermost layer of a tree, helping to keep out moisture.

Advantages of Wood

• Workability: wood is easy to work with.
• Non-Conductor of Heat: wood is a poor conductor of heat.
• Flexible & Durable: wood is flexible and durable.
• Lightweight: wood is a lightweight material.

Disadvantages of Wood

• Shrinkage and Swelling: wood can shrink and swell with changes in humidity.
• Fire Vulnerability: wood is vulnerable to fire.
• Moisture and Water Damage: wood can be damaged by moisture and water.
• Pest and Fungi: wood can be damaged by pests and fungi.

Types of Wood

• Hardwood: comes from deciduous trees (e.g. Narra, Yakal, and Gujo).
• Softwood: comes from conifers (e.g. Pine).

Philippine Timber

• Group 1: Ph Timber (Acacia, Agoho, Oak, Pili, and Malabayabas).
• Group 2: Ph Timber (Bakawan, Malakamias, and Malasaging).
• Group 3: Ph Timber (Yakal, a hard and golden mahogany type).

Preparation of Wood

• Cutting: the first step in preparing wood.
• Skidding: the process of moving felled trees to a landing area.
• Bucking: the process of cutting felled trees into manageable sections.

Illegal Logging

• Section 68: illegal logging is prohibited in the Philippines.

Wood Measurement

• Board Foot: a unit of measurement of volume of lumber, calculated by multiplying thickness, width, and length ( Formula: thickness x width x length / 12).
• Formula for Board Foot for Slabs: (Diameter - 4)sq x Length / 16.

Defects in Wood

• Abnormal Growth: defective wood growth.
• Deterioration: decay or rot in wood.

Wood Seasoning

• Air Seasoning: natural drying of wood.
• Forced Air Drying: artificial drying of wood using air.
• Kiln Drying: artificial drying of wood using heat.
• Radio Frequency Drying: artificial drying of wood using radio frequency energy.

Plywood

• Lightweight, made of thin veneers of wood.
• Softwood: most common type of plywood for structural use.
• Hardwood: most common type of plywood for paneling and finishing.

Grades of Plywood

• Grade A: free from defects, smooth.
• Grade B: sanded but with few defects.
• Grade C: unsanded.
• Grade D: unsanded, 1 1/2" wide.

Engineered Wood Products

• Hardboard (HDF): compressed, high-density fiberboard for cabinets and toilets.
• Particle Board (LDF): engineered wood made from chips and resin.
• MDF: medium-density fiberboard, denser than LDF, used in 4ft x 8ft sheets.