CONSTRUCTION TECHNOLOGY 1 LEC 04

CETE 101: Construction Technology 1 Overview

Wood

• Defined by the National Structural Code of the Philippines (NSCP) as:

  • Hard, fibrous tissue found in the stems and roots of trees.

Lumber

• Processed wood into uniform sizes, ready for construction.

• Types of Lumber:

  • Rough Lumber: Raw material for multiple uses.

  • Finished Lumber: Processed wood, ready for use with minimal cutting.

Timber

• Defined as square or nearly square sawn lumber, at least 125 mm wide, used in various building parts.

NSCP

• The National Structural Code of the Philippines

Key Components of Wood Framing:

• Studs: Vertical wood members used in walls

• Joists: Horizontal wood members that support floor and ceilings

• Rafters: Sloped wood members that support the roof structure

• Sills: Horizontal and treated wood members that lay directly on the foundation, and provide base for the wall framing

• Headers: Horizontal wood members placed above door and window openings to support the weight from above

• Plates: Horizontal wood members at the top and bottom of walls

  • Sole plate or Bottom plate: Bottom

  • Top plate: Top

• Sheathing: Panels attached to the exterior of the framing to provide structural stability and a base for exterior finishes

• Diagonal Subfloor: Provides structural integrity.

• Double Joists: Supports weight.

• Solid Bridging: Connects joists for strength.

• Plywood Subfloor: Acts as a base layer.

• Anchored Sill: Secures the structure.

• Lapped Joists: Joined at the girder.

• Space for Sheathing: Needed in joist arrangements.

Definition of Board Foot

• Measurement unit for lumber volume despite metric usage.

• 1 board foot = 1 sq. ft. x 1 inch thick = 144 cubic inches.

Calculation Example

• Volume calculation: 12 in. x 12 in. x 1 in. = 144 cu. in. = 1 board foot.

Nominal Sizing

Understanding Sizing Differences

• Nominal Size: Original dimensions before drying/planing, used in merchandising.

• Actual Size: Smaller, due to drying and planing processes.

• Drying: As wood dries, it shrinks in width and thickness.

• Planing:The planing process removes up to ¼ inch from both dimensions of the wood.

• Examples of Size Reduction:

  • 1" x 2" nominal becomes 3/4" x 1 1/2" actual.

  • Planing can remove up to 1/4 inch from both dimensions.

According to the National Institute of Standards American Softwood Lumber Standard (PS 20)

Nominal Actual