How much does Loft Insulation Cost UK? Loft insulation costs can vary greatly depending on the material used for the task or whether you insert it yourself or hire an insulation professional. Keep in mind that if you choose to install it yourself, you will not have access to all of the different material options. “The overall cost of loft insulation in the UK is between £5 to £11/m²”. This means that it should cost no more than about £1250 to insulate a 4-bedroom detached home. The average labour cost and supplies for loft insulation are £500.  According to the insulation experts, this fluctuates from £400 for a detached house to £600 for a semi-detached house or bungalow. This price is for blanket insulation installation and includes both the material and the labour. If you are planning to lay your own loft insulation, you might choose blanket insulation, which does not cost much.  Please remember that if you desire natural sheep's wool insulation, it can be a bi