Loft Insulation Calculator
Calculate how much loft insulation you need to meet UK building regulations. Works with existing insulation.
How to use this calculator
1. Measure your loft
Measure the length and width of your loft floor space in metres.
2. Check existing insulation
Measure the depth of any existing insulation between the joists.
3. Choose target depth
Select 270mm minimum or higher for better energy savings.
4. Select insulation type
Choose mineral wool rolls, PIR boards, or rockwool slabs.
5. Calculate materials
Click Calculate to see how many rolls or boards you need.