Home & Construction5 min read
Roof Pitch Ratio: Rise per 12 Inches of Run
Roof pitch is rise ÷ run × 12, quoted as 'x in 12'. A 2 unit rise over an 8 unit run is a 3 in 12 pitch, about 14 degrees. Includes rafter length.
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- Home & Construction4 min read
Energy to Heat a Room: m × c × ΔT in kJ and kWh
Raising 100 kg of water by 10 °C takes 4,180 kJ, and 150 m³ of room air by 10 °C only about 1,809 kJ. See the m × c × ΔT sum and a heater run time.
- Home & Construction4 min read
Screed Volume: Floor Area × Thickness
A 70 m² floor screeded 50 mm deep needs 3.5 m³ of mix, about 3.85 m³ with a 10% allowance. Convert thickness to metres and order with confidence.
- Home & Construction4 min read
How to Work Out Stair Riser Height
Divide the total rise by the number of risers: a 280 cm floor-to-floor gap over 16 steps gives 17.5 cm per riser. See how to pick the count and check comfort.
- Home & Construction5 min read
Steel Weight Formula for Plates, Bars and Pipes
Steel weighs about 7,850 kg per cubic metre. A 2 m × 1 m plate that is 10 mm thick is 0.02 m³, which comes to 157 kg. Here is the method for any shape.
- Home & Construction5 min read
How Much Grout Do You Need for a Tiled Area?
Grout fills thin joints, so volume is tile edge length × width × depth. 20 m² of 300 mm tiles with 3 × 5 mm joints needs about 2.0 L of grout before waste.
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