A landlord had fire-rated downlights fitted throughout an HMO loft conversion, then two years later a contractor topping up the loft insulation buried every fitting under 300mm of mineral wool, pressed right against the housings. The downlights were fire-rated, but once insulated that way, the installation wasn't automatically safe. This guide covers why a fire rating doesn't cover every insulation scenario on its own, what a fire-rated loft cone actually does to prevent overheating, and what to check before a loft re-insulation job buries existing downlights that were never fitted with one.