Applied Engineering Math
Ratios in Construction & Building
From material mixing ratios to scale blueprints and roof pitch gradients, proportional accuracy ensures structural safety and compliance.
1. Concrete & Mortar Mixing Ratios
Building materials must be mixed in exact volumetric ratios to attain specified compressive strengths (PSI):
🏗️ Standard Concrete (C20/25)
1 : 2 : 3 (Cement : Sand : Coarse Gravel)
1 part Portland cement, 2 parts clean sand, and 3 parts aggregate stone by volume.
🧱 Bricklaying Mortar (Type N)
1 : 1 : 6 (Cement : Lime : Mason Sand)
Standard residential load-bearing exterior wall mortar offering flexibility and bond strength.
2. Scale Drawings and Blueprints (1:50 & 1:100)
Architectural blueprints translate real building dimensions to paper using standard reduction ratios:
- 1 : 50 Scale: Every 1 centimeter on the plan equals 50 centimeters (0.5 meters) in reality. A 6-meter wall measures
600 cm ÷ 50 = 12 cmon paper. - 1 : 100 Scale: 1 cm on paper equals 100 cm (1 meter) in reality.
3. Roof Pitch and Slope Ratios
Roof pitch represents the vertical rise over a horizontal run of 12 units (e.g. 4 : 12 pitch means 4 inches of vertical rise for every 12 inches of horizontal run).