Loft Insulation Calculator
Work out how many rolls of insulation you need to properly insulate your loft and save on energy bills.
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Frequently Asked Questions
What is the recommended depth for loft insulation?
The UK government recommends a minimum depth of 270mm of mineral wool insulation to maximize energy efficiency and reduce heating bills.
Do I need gloves to lay loft insulation?
Yes. Mineral wool insulation contains fine glass fibers that can severely irritate the skin, eyes, and lungs. Always wear a dust mask, goggles, gloves, and long sleeves.
Should I insulate between or over the joists?
Both. To achieve the 270mm depth, a base layer (usually 100mm) is laid tightly between the joists, and a top-up layer (usually 170mm or 200mm) is laid at a 90-degree angle right across the top of the joists to prevent cold bridging.
Can I compress loft insulation under boards?
No. Compressing insulation squeezes out the trapped air pockets that actually provide the heat retention. If you want to board your loft for storage, you must use raised loft legs.