Terrain Category 2.5

Overview

Terrain Category 2.5 (TC 2.5) describes terrain with a few or isolated obstructions, representing an intermediate classification between TC 2 and TC 3. It is typically used for developing outer urban areas or large acreage sites with scattered buildings or vegetation.

Why This Is Important

Provides a more accurate classification for areas that don’t clearly fit into TC 2 or TC 3.
Ensures appropriate wind loading calculations in semi-developed zones.
Helps guide estimators and engineers in selecting the correct terrain factor.

Examples

Small acreage subdivisions with fewer than 1 house per 1,000 m² (or 10 per hectare)
Areas with 2 to 10 large trees, groups of trees, or buildings per hectare (≈ 25–140 per cardinal sector)

In cyclonic areas, terrain with:
- Vegetation or high crops (≥ 600 mm), such as:
  - Sugar cane
  - Wheat
  - Vineyards

Tips, Best Practices & Troubleshooting

Use satellite imagery to count obstructions per hectare for classification.
For borderline cases between TC 2.5 and TC 3, consult engineering support.
Consider local vegetation and building density in all directions (cardinal sectors).

Terrain Category 1

Terrain Category 2

Terrain Category 3

Site Specific Engineering

Request Engineering (Site Check)