Roof and heat: colour, insulation, height, open ridge
At 2 p.m. in March, a bare sheet in the sun reaches 60 to 70 °C. It is 2.8 m above the chickens, and it radiates onto them like the plate of an open oven. In an open-sided house, the roof is both enemy number one (it catches the sun) and ally number one (it gives shade and pulls the hot air upwards). This lesson explains how a roof heats a house, and gives the four levers to make it cool the house instead of heating it: colour, insulation, height and the open ridge, with measured temperatures and the quantities to plan.
13 min read · 5-question quiz at the end
By Abdul Hussein ChoumanFounder of NEXTEKCI · Agnibilékrou hatchery since 2006This lesson is part of Designing and building a poultry house specialisation. It opens to every registered student, from free registration. Levels 1 to 5 and the tracks remain readable by everyone.
At 2 p.m. in March, a bare sheet in the sun reaches 60 to 70 °C. It is 2.8 m above the chickens, and it radiates onto them like the plate of an open oven. In an open-sided house, the roof is both enemy number one (it catches the sun) and ally number one (it gives shade and pulls the hot air upwards). This lesson explains how a roof heats a house, and gives the four levers to make it cool the house instead of heating it: colour, insulation, height and the open ridge, with measured temperatures and the quantities to plan.
- ✓Explain how the heat of the roof reaches the birds (radiation, trapped hot air) and measure the temperature of a sheet
- ✓Choose the colour and the paint of the roof, and calculate the quantity of paint for 467 m²
- ✓Compare the insulation solutions available (mat under-roof, ventilated false ceiling, double roof) and know when they are worth it
- ✓Size the ridge vent and check that it draws, then combine tree shade, roof sprinkling and fans
- How a roof heats a house
- Colour: the cheapest and most forgotten lever
- Insulation: putting something between the sheet and the birds
- Height and slope: moving the source away
- The open ridge: the chimney of the house
- The complements: trees, sprinkling, fans
- Going further
- •A bare sheet reaches 60 to 70 °C at 2 p.m. and radiates onto the birds; the chicken receives heat through the air, the floor and the radiation of the roof.
- •White: sheet at 40-45 °C instead of 62-68, 2 to 4 °C less below; acrylic 135 L for 467 m² every 4 to 6 years, or lime 210 kg every year in February.
- •Insulation: mats under the purlins (2-3 °C), ventilated false ceiling (3-5 °C), double roof; always a free ridge and a ventilated void.
- •Height 2.8 m under the eave and 35% slope: 1,120 m³ of air for 1,600 broilers (0.7 m³ each); the hot air slides towards the ridge.
- •Ridge vent 0.4 × 40 m = 16 m² = 5% of the floor area, cap at 0.3 m; smoke test at 1 p.m.; trees, roof sprinkling (1-2 L/m²) and fans as complements.