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Floor insulation

About 10% of heat loss from an average home is through the ground floor. If your floor isn't already insulated, this could be a good move to help you cut your energy bills. Not sure whether you already have floor insulation, or want to install it but don't know how? Read on to find out more about floor insulation and what's the right option for your home.
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Worker installing floor insulation

Do you need to insulate your floor?

There's no point in investing in expensive floor insulation if you don't need it, or if it's unsuitable for your home, but how do you know one way or the other?

Whether you need floor insulation or not depends on your home and what kind of floors it has:

  • Older houses with 'suspended floors', which are in effect above a void, are likely to lose more heat through the floor.

  • Homes with solid (concrete) floors, built since the 1930s, have less of a problem. Concrete floor insulation can, however, be installed and usually consists in a layer of solid insulation which is placed directly on the floor.

  • Modern houses tend to incorporate slabs of polystyrene insulation a few inches below the concrete floor surface, effectively reducing this type of heat loss.

Whatever your home, there's still some kind of measure you can take to insulate your floor.

Four ways to insulate your floor

  • Draught-proofing - simply use sealant or caulking to fill the gaps between your floorboards and between skirting boards and the floor.

  • Add an insulating layer under your carpet or floor-covering - try a fibreboard underlay or polyfoam board.

  • A rug - it's not going to solve all your problems, but putting a rug on top of bare floorboards will help to block some draughts and keep your toes warm.

  • Underfloor insulation - if you have you an access hatch that allows you to get into the crawlspace (void) below the floorboards, this is a relatively easy process, if not you will have to take up the floorboards. You will need to use netting or wooden battens to hold the glass or mineral wool style insulation in place beneath the floorboards. Alternatively, it may be easier to use batts rather than blanket style insulation. Batts typically also have the advantage of having a slightly higher R-value - the higher the R-value, the greater the insulator's effectiveness. Sheep's wool could also be considered, due to its breathability.

One thing to remember, however, is the need for ventilation. The void (or crawlspace) below the floorboards will have ventilation grills and these should not be blocked up, as floorboards may otherwise become damp and start to rot.

What else should you insulate in the home?

While floor insulation is a great way to save money, it is by no means the first form of insulation you should look at around your home.

Loft insulation

If your property has a roof with attic space then loft insulation is the first thing you should look at, particularly since an estimated 25% of the heat in your home is lost through the loft.

Loft insulation is cheap to buy, easy to install (you can even do it yourself) and can save you serious amounts of money over the years.

Even if you already have loft insulation in place it may be worth checking whether you have the recommended levels installed. The recommended depth for blanket-style insulation is between 250 and 270mm. If your loft insulation was installed some time ago there's a good chance it's less than that.

And even though loft insulation is cheap to buy and install, it's also possible to receive grants towards your loft insulation.

Wall insulation

While significantly more expensive to install than loft insulation, wall insulation could save you even more money over the long term.

Wall insulation is typically divided into two types, depending on what type of home you have. Cavity wall insulation, typically suitable for homes built after 1930, consists of pumping insulation into the space between the outer and the inner walls. Solid wall insulation, for homes built earlier, insulates around the outer wall itself.

If your home was built more recently still there's a good chance you will already have cavity wall insulation in place but now know about it.

The problem with this form of insulation is that you will usually need help getting it installed. For cavity wall for instance, holes have to be drilled into your wall through which the insulation material is pumped.

Luckily there are plenty of energy efficiency grants that will help you pay for the costs of wall insulation.


If installing proper insulation sounds like too much work, don't worry - there is a quick fix solution that could still save you money and energy and is cheap to buy and easy to do yourself.

Draught proofing is all about securing the cracks and spaces around typically areas of heat loss around the home. The most common culprits are windows and doors (and their frames), but you should also check for draughts around letterboxes and chimneys.

Luckily it's also an easy problem to solve. Draught-proofing materials like draught-proofing strips can be placed around casements, or you can use putty or sealant in any clear cracks.For the big gaps between the bottom of your door and the frame meanwhile you can buy brushes or hinged draught-excluders that can be easily attached. Similarly letterboxes can be sealed with flaps or brushes, like the EcoFlap.

For bigger gaps like chimneys you need specialised products. A chimney balloon is inflated and inserted up your chimney flue or, better still, if you don't use your chimney you can simply have it capped off at the top.

Read more:

Solid and cavity wall insulation - Uswitch

Learn about different wall insulation types, including cavity wall insulation and solid wall insulation, and find out which wall insulation is right for your home with Uswitch.

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Window insulation and double glazing - Uswitch

There's more to window insulation than double glazing. Find out about professional and DIY window insulation and how it can cut your heating bill.

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Draught-proofing your home - Uswitch

Draught-proofing is a cheap way to prevent heat loss, cut your energy bills and warm up your home. Find out how to draught-proof your home and save money.

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