How to install electric underfloor heating

January 2022 – Special Offer! For this month only we are giving away a free underfloor heating cable with every order of our Cableflor Heating Tile, while stocks last. So that’s only £72 per sqm for a heated floor, no builders required! Email to place your order.

Our Cableflor underfloor heating kit is very quick and easy to fit, with no experience or special tools needed.

Here is a short video that shows you how you can lay a heated floor in a Garden Room, which is the same for lofts, home offices or anywhere that already has an insulated floor.

Running Costs: We have two live set ups of our kits – one is in a garden room and the other is in an office conversion in a barn. They’ve both been running since October 21 and we have been recording the temperature inside and outside, together with the actual running costs.

The garden room (3m x 5m) is averaging 87p a day to run, whilst the office (4m x 3.5m) is averaging 78p a day – if you would like the read outs for either scenario, please email

Click here to see our Bundle Offer price

Installing electric underfloor heating in a garage or cellar

If you want to lay underfloor heating onto a solid concrete floor (where there is no insulation), it’s still very easy to fit.

There’s only three more steps to the installation, and a couple of extra things needed. All the materials are relatively cheap and widely available on-line.

Here is our step-by-step guide:

Step 1

To install electric underfloor heating on a concrete floor such as a garage, cellar or outbuilding, the first step is to lay a damp proof membrane. This is basically a big plastic sheet that you can buy cheaply on-line.

Simply roll it out and cut it to size with a pair of scissors – ensure that you run it up the wall by about 6 inches / 15cms. You can hold it in place with some duct tape to make it easier for the next step.

damp proof membrane

Step 2

Lay down insulation boards. This step is important as you can lose a lot of your heat through a concrete floor. Boards are also widely available on the internet and they deliver directly to your house. They’re very lightweight, a bit like polystyrene with silver foil on either side.

Trim to size with a handsaw – they’re very easy to cut but don’t forget to wear a face mask.

Step 3

Next use standard sheets of flooring chipboard to cover the insulation. These can also easily be purchased online, and usually from the same supplier as the other elements. Each sheet has a tongue and groove along the edge, so you can push the the boards together to create a solid base. Trim to size with a saw and trim off the excess damp proof membrane. You are now ready to install electric underfloor heating.

underfloor heating assembly

Step 4

Using an underfloor heating cable is so much easier than using pre-assembled mats and work out cheaper. The benefit of using a cable is that you can fit it to any shape or size. It’s easy to go around obstacles or areas that don’t need heating (such as under cupboards etc.). Make sure the end that is going to be wired into the thermostat is near you power source for easy connection.

Stick the cable down in rows with a 10cm gap between them. Mark it out with pencil first as a guide.

underfloor heating assembly

Step 5

Our raised floor tiles are supplied in metre square sheets for rapid assembly – each sheet just clips into the next.

Ensure that the cable sits in the channel on the underside of the tile. You can trim the floor tiles to the nearest 10cm by simply unclipping tiles or tearing off whole rows. Cover the whole area.

underfloor heating assembly

underfloor heating installation

Step 6

To finish off the floor, use Karndean Loose Lay vinyl. We are a reseller and use it because of its thermal properties and high quality finish. There are 39 different ones to choose from, in wood and stone finish. Start laying in rows and when you get to the end of the first run, trim it to size. Use the off-cut to start the next row to avoid any waste.

It’s really easy to trim with a Stanley or craft knife – just score it where required, bend it and then trim off. The underside has a foam backing which ‘grips’ our floor, so you don’t need to use any glue if fitted tightly against the walls. If you would prefer to glue it, Karndean also supply a tackifier. This is a low odour adhesive which you can roller on to the Cableflor.

underfloor heating installation

That’s all there is to it – most floors can be fitted comfortably over a weekend. If you’re installing Cableflor in a loft, our raised floor tiles are very lightweight to make it easier to get it up there. The added benefit is that they can be torn into smaller sections if you need to get it through a loft hatch.

Use a qualified electrician to make the connections into the thermostat and power source.

UPDATE 10/1/22 – We finally got around to finishing our office, here are some photos:

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