Loft insulation is one of the most cost-effective ways to reduce heat loss. It creates a thermal barrier between your living space and the cold roof space above, keeping warmth where you actually live.
Check access and condition – Make sure your loft is dry, ventilated, and safe to move around.
Clear the loft floor – Remove stored items and old insulation if it’s damaged or damp.
Lay the first layer – Roll out mineral wool insulation between joists (usually 100 mm thick).
Add the top layer – Lay another 170–200 mm crosswise over the joists to reach around 270–300 mm total thickness.
Avoid blocking ventilation – Keep air gaps around eaves clear to prevent condensation.
Insulate loft hatch – Add draught-proofing strips and insulation to the underside of the hatch.
Replace boarding (optional) – If you need storage, install raised floor boards above the insulation.