To determine if your floor has a void under the floorboards, check whether the floorboards are supported by joists. This void can lead to significant heat loss if not addressed, so insulating it with materials such as insulation rolls or boards can help reduce heating costs and improve comfort in your home. Suspended floor insulation is ideal for homes with a basement or void beneath the floor. This allows easy access to the space below, where insulation can be secured using covering materials. Insulation slabs or boards can be fitted tightly into the gaps, and insulation netting can be rolled out and attached at each joist for added stability.

In some cases, if your home doesn’t have a basement or cellar, and the floor is still suspended, the floorboards will need to be lifted to access the void beneath. This process is best done alongside other major tasks like plastering or painting, as it requires emptying the room of furniture. After lifting the floorboards, rigid insulation boards should be cut to fit snugly between the joists, ensuring no gaps for air to escape.

An alternative method is to use insulation rolls, like natural sheep’s wool, secured with inexpensive insulation netting underneath the joists. The netting should be draped low enough to accommodate the insulation’s thickness, and the roll should be laid out to cover the width of the joists.

Be cautious of airbricks in external walls, as blocking them can cause floorboards to rot due to lack of ventilation. Ensure these airbricks are at least 2 inches below the insulation to maintain proper airflow.