My Loft Has Old Insulation That’s Below The Joists. Should I Remove It Or Just Top It Up?

In most cases, you can simply top it up. If the existing insulation is dry, in good condition, and not made from hazardous materials, laying new insulation over the top is standard practice. The key is to ensure you reach the total recommended depth of 270mm. However, if the old insulation is damp, heavily compressed, or shows signs of pest infestation, it must be safely removed and the underlying cause of the problem (like a leak or poor ventilation) must be fixed before new material is installed.

Is There Such A Thing As Too Much Loft Insulation?

Yes, you can have too much loft insulation, but the primary issue is not the insulation itself, but the consequences of improper installation.The main problem with excessive or incorrectly fitted loft insulation is that it can block ventilation points, particularly at the eaves. This traps warm, moist air rising from your home, leading to condensation in the roof space. This can cause: Damp and mould growthRotting of timber joists and roof structuresReduced effectiveness of the insulation if it becomes wet In the UK, the recommended depth is 270mm. The key is to insulate to the recommended depth while ensuring a clear gap is left for ventilation.

Should I Install Loft Insulation Between Joists or Rafters?

If the loft is unused and unheated, insulate between and over joists to create a cold loft. If the loft is used as a living space, insulate between rafters to keep the area warm.

Loft Insulation | Attic Insulation

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Loft Insulation

130mm Celotex XR4130 PIR Insulation Board 2400mm x 1200mm

200mm Knauf Loft Roll 44 Insulation Combi-Cut - Pallet of 24 Rolls (164.16m2/Pallet)

100mm Knauf Loft Roll 44 Insulation Combi-Cut - Pallet of 24 Rolls (333.24m2/Pallet)

110mm Celotex XR4110 PIR Insulation Board 2400mm x 1200mm

125mm Unilin Xtratherm Thin-R PIR Insulation Board 2400mm x 1200mm

150mm Knauf Loft Roll 44 Insulation Combi-Cut - Pallet of 24 Rolls (220.25m2/Pallet)

165mm Celotex XR4165 PIR Insulation Board 2400mm x 1200mm

200mm Celotex XR4200 PIR Insulation Board 2400mm x 1200mm

170mm Knauf Loft Roll 44 Insulation Combi-Cut - Pallet of 24 Rolls (192.34m2/Pallet)

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