Underfloor Heating Insulation

Floor insulation.
  • 5-8 hours
  • Advanced
  • 900-2,000
What You'll Need
Insulating tape
Staple gun
Fiberglass insulation
Pipe insulation
Wood strips

Underfloor heating systems are popular ways to heat houses and that's why many people are starting to use underfloor heating insulation. A room should be properly insulated because you will end up spending very large amounts of money if is not. Insulating the floor of your home will make it much easier and less expensive to heat the home.

Floor insulation will be especially important if your room is situated above an unheated area in your home. Rooms above an unheated basement, for example, can suffer from extensive heat loss from the floor and that's why underfloor heating insulation is so useful. Installing your own underfloor heating insulation is very easy and is something that you should take some extra time to do whenever you are installing underfloor heating in your home.

Step 1 - Add Wooden Lathing

Assuming your floor is made with joists, you need to install wood lath strips that span the joists. This will be used to hold the insulation material in place, while still allowing the air to circulate. The gap between these strips should be approximately 12 inches. The wood lath strips can then be nailed or stapled to fix them into position. Try to keep these wooden lath strips straight, and square, where possible. Also ensure that they are perfectly level.

Step 2 - Instal Insulation

Before you start handling fiberglass insulation, you must put on gloves. Fiberglass can be irritating to the skin so it is important to protect yourself. This fiberglass insulation material then needs to be packed into the spaces between the joists. Ideally, you should be using insulation with a vapor barrier attached to the back, if not you will need to fit a separate vapor barrier. Be sure you do not insert the insulation in too tightly because this will make it less effective. Don't risk damaging any electrical wiring or plumbing, instead, fit the insulation material under the pipes and wires.

Step 3 - Insulate Water Pipes

If there are any hot water pipes that flow through the void under the floor, you should ensure these are correctly insulated. Try to choose R3 insulation for areas that have harsh winters. Insulating water pipes will help to prevent any unnecessary heat losses from the water pipes.

Step 4 - Fit the Heated Floor

Once you have finished fitting the underfloor heating insulation, you are ready to continue fitting the radiant heated floor as normal. This needs to be stretched over the top of the newly fitted insulation and held down as normal. The extra insulation should make the whole system much more efficient and effective. Insulation can sometimes seem like a waste of time, but it will pay for itself. Fitting insulation under the floor should be treated as an investment because your heating bill will certainly show you the savings.