Without underfloor insulation, you can lose roughly 15% of the heat from your home, so the ground floor and any upstairs rooms above unheated areas should be suitably insulated. According to the Energy Saving Trust, installing floor insulation could save you up to £65 on heating bills and 290kg of carbon dioxide emissions annually.
What should I check before installing floor insulation?
Those of you who want to carry out the underfloor insulation installation yourselves should be aware that it can be a rather large undertaking. Careful planning is required, as is a good understanding of the materials you’re using. Installing too little won’t give you the desired effect; too much and the floor height will rise, so door heights, skirting boards, window sills, sockets, and even electrical wiring will need adjusting.
Older buildings tend to have a suspended floor structure, where floorboards are fixed onto joists above an empty void (or ‘crawlspace’).
If you have access to the crawlspace beneath the floor, the job should be fairly simple. Boards or blankets of insulation can be fitted between the joists (aim to fit at least 100mm rigid foam or 150mm blanket insulation). Semi-rigid insulation can often be friction fitted or held up by battens attached to the bottom of the joist.
Alternatively, blanket insulation will need to be held up by netting and tacks stuck into the joists. Depending on available space, solid board insulation can then be screwed into the bottom of the joists to provide extra padding and draught-proofing.
It’s important that the insulation won’t interfere with any underfloor ventilation system in the crawlspace, so steer clear any air blocks in the wall. Blocking grilles or air blocks can lead to serious hazards given time, such as rotting floorboards or a build-up of carbon monoxide. However, you can block these cold draughts from coming up through the floor – use sealant or caulking to fill any gaps you may find between the floorboards and around the skirting boards.
Most modern homes come with insulation already installed beneath the concrete floor surface, the advantage of this being that concrete absorbs and stores heat well, which keeps your house warmer for longer overnight.
ECO4 is backed by large and medium energy suppliers. They have legal obligations under the Energy Company Obligation (ECO) scheme. This includes companies like British Gas, EDF Energy, E.ON, Scottish Power, and Octopus Energy.
For more information please go to the government’s Ofgem website.