As much as 25% of all the heat lost from an average home escapes through the roof. Over a half million homes have no attic insulation at all.
Most Irish houses have some attic insulation, but the majority with 100mm (4 inches) or less should be substantially topped-up to around 270mm (11 inches), the requirement for new homes. The loft insulation material is rolled between the joists and may then be applied in a second layer across the joists to avoid cold-bridging.