How much loft insulation do I need?
Depth matters, but so does condition. Deep insulation that’s damp or squashed doesn’t do much.
| Recommended depth (mineral wool) | 270mm in total |
|---|---|
| Made up of | A layer between the joists plus a layer across them |
| Other materials | Depth depends on their thermal conductivity |
The depth
For mineral wool, around 270 mm is commonly recommended. Other materials need slightly different depths.
Condition counts
Insulation that’s flattened, wet or soiled loses much of its value however deep it once was.
Common questions
Can you check it for me?
Yes. Book a free loft check on the form.
Tell us what you’ve found. We’ll find the cause.
Describe the problem and we’ll look, explain it and quote the fix in writing. Free.