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How to install foil underfloor heating

Updated: October 2026

You have a roll of foil mat for a UK room and you want to know which parts you can do yourself. How to install foil underfloor heating, on this page, means measuring the free floor, laying the mat the listing allows, and stopping where a competent person has to connect the circuit. In England that connection can be notifiable. Laying the mat does not take the job outside the Building Regulations. The [electric underfloor heating foil comparison](/hub/heating/underfloor-heating-foil) holds the nine listings. This page does not rank them. If you buy through our links, a qualifying purchase can earn us a commission at no extra cost to you.

You have a roll of foil mat for a UK room and you want to know which parts you can do yourself.

Our top picks

Adept Adept dial-thermostat foil kit

Best overall

Adept Adept dial-thermostat foil kit
9.6/10about £54.99
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Adept Adept 10 m² foil kit

Preis-Tipp

Adept Adept 10 m² foil kit
9.0/10about £164.99
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Minco Minco film 50 cm × 2 m

Alternative

Minco Minco film 50 cm × 2 m
1.0/10about £35.99
View offer
On this page
  1. 1.What you measure first
  2. 2.What goes under and above the foil
  3. 3.What you must not cut
  4. 4.When an electrician takes over

What you measure first

Measure the free floor and keep the mat out from under fixed units. A 10 m² kit is the wrong buy when the clear floor is closer to 7 m², because spare heating cable cannot be folded into a corner. Adept says the mat can be shaped. That is not permission to cut the heating cable. The dial kit and HM140/7 do not print coverage. A clear hall of 3.2 m by 1.1 m is about 3.5 m² before a margin at the walls. Take that figure, not the whole room including fitted furniture. The underfloor heating foil buying guide puts supply and thermostat beside it.

What goes under and above the foil

Insulation sits under the mat, and the floor finish sits above it. Approved Document L treats heat loss through the floor as part of the ground-floor design. Warmup asks for at least 6 mm of soft insulation under its own foil heater. Adept’s listings here do not state 6 mm, so that figure stays on Warmup’s manual. A dial-kit review dated 13 December 2023 describes 2 mm red underlay the reviewer called suitable, under LVT. That is one install, not a specification for every laminate. Put the probe where that kit’s manual tells you. This set does not print a single room-centre position. Board limits and the carpet exclusion are on the underfloor heating foil under laminate page. Covering the mat before the electrical tests is how a later fault becomes a floor you have to lift.
Adept Adept dial-thermostat foil kit

Testsieger

Adept Adept dial-thermostat foil kit
9.6/10about £54.99
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What you must not cut

Shaping the mat is not cutting the heating cable. Adept says the mat can be shaped to the free floor and does not say the cable can be cut. If you nick the cable on a turn, the listing has not given you a repair step. Minco’s film may be shortened every 25 cm. That pitch is for Minco’s film only. It is not permission to cut an Adept cable, and it is not permission to shorten the 12 V vehicle film. Warmup tells its installers to bridge cut gaps with foil strips. Those are Warmup’s steps. Adept’s bullets do not publish that bridge-strip instruction. Follow the manual in the carton you have.

When an electrician takes over

You can lay the mat. A competent person connects it, and notifies where the rule requires it, before the floor covering goes down. In England, fixed equipment in a dwelling sits within Part P. Approved Document P (2013) is the guidance. The work is notifiable when regulation 12(6A) applies: a new circuit, a replacement consumer unit, and special locations. A new circuit for this mat is the case to plan for. Wales, Scotland, and Northern Ireland do not use this England list as their own rule. This page does not state an RCD milliamp figure. The March 2020 dial-kit note says the back box was extra. On the touchscreen line, a display went blank in December 2023 after a September 2022 install, and the seller sent a replacement the next morning. Book the person who will test and connect before the boards lock the wiring.

Common questions

Who connects it in England?
A competent person connects the thermostat and the supply, and notifies building control where regulation 12(6A) requires it. Reviewers who fitted the dial kit still describe a test meter for the earth path and a back box that was not in the carton. If you are not that person, book one before the floor covering goes down, because a later probe or display fault is harder to reach once the boards are locked.
Is a new circuit notifiable?
In England, a new circuit sits in the notification cases in regulation 12(6A), with a replacement consumer unit and work in a special location. Approved Document P (2013) is the Part P guidance. Other dwelling work still has to comply when it is not on that list. Wales, Scotland, and Northern Ireland use their own rules.
What goes under the mat?
Insulation belongs under the heater, and the floor finish belongs above it. Approved Document L is the England text that brings floor heat loss into the design. Warmup asks for at least 6 mm of soft insulation under its own foil. Adept’s listings here do not state 6 mm, so that figure stays on Warmup’s manual. One Adept reviewer used 2 mm underlay under LVT and called it suitable. That is one install, not a universal build-up.
Can I cut the heating cable?
Adept does not state that the heating cable can be cut. The listing says the mat can be shaped to the free floor. Minco’s film can be shortened every 25 cm, and that pitch is only for Minco’s film. Warmup’s instruction to bridge cut gaps with foil strips is Warmup’s manual, not a step printed on these Adept rows. Cut only what the listing you bought allows.
Where does the floor probe go?
Follow the position in the manual for the kit you bought. The dial-kit box list in a March 2020 review includes a flexible probe tube. A later review on the white-thermostat line describes a floor-probe fault that could not be diagnosed until the seller supplied the probe specifications. Keep those details. This set does not print a single centre-of-the-room rule you can use for every mat.

Related pages

Before you lay underfloor heating foil

Underfloor heating foil 2026

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Best electric foil underfloor heating, star or value

Underfloor heating foil buying guide: what to decide

Underfloor heating foil under laminate: named finish

Sources

Public UK sources and the amazon.co.uk listings in this comparison. Listings captured 15 October 2026. Page updated October 2026.

  1. Approved Document P, 2013 (retrieved 15 October 2026)
  2. Approved Document L, 2021 with 2023 amendments (retrieved 15 October 2026)
  3. Approved Document L, 2026 (retrieved 15 October 2026)
  4. Building Regulations 2010, regulation 12 (retrieved 15 October 2026)
  5. Consumer Rights Act 2015, section 9 (retrieved 15 October 2026)
  6. IET, BS 7671 (retrieved 15 October 2026)
  7. Warmup foil heater (retrieved 15 October 2026)
  8. amazon.co.uk listing extract, Adept 3 m² foil kit (retrieved 15 October 2026)