Low Profile 18mm Overlay UFH Kit 84m² | 7-Port Grundfos Pump

Description

This ThermRite 18mm Overlay Underfloor Heating Kit is a complete, ready-to-install wet (warm water) underfloor heating system covering 84m². It is designed for a large multi-room floor plan or commercial space with up to seven independently controlled zones, laid straight over an existing solid or timber floor as a floating floor with a floating wood, laminate or engineered timber finish on top. There is no screed, no adhesive and only 18mm of build-up, so it is ideal for retrofit, renovation and extension work where floor height matters.

The kit combines 117 foil-faced EPS panels routed for 12mm pipe at 150mm centres, 560m of 12mm multilayer pipe, a 7-port stainless steel manifold fitted with an A-rated Grundfos pump and thermostatic mixing valve, and the pipe cutter and reaming tool you need to lay, connect and commission the system. The metallised foil surface and insulating EPS core mean heat spreads quickly and evenly across the floor, with less heat lost downwards into the subfloor.

84m²

Kit coverage

18mm

Overlay build height

150mm

Pipe centres

7

Manifold ports

560m

12mm pipe supplied

117

18mm panels supplied

Test before you cover

Install, pressure test and commission this system in line with the manufacturer's instructions and current UK Building Regulations, using a competent installer. Pressure test and inspect the pipework before the floor finish is laid. The maximum floor surface temperature for wood and laminate is generally 27°C, so confirm the limit with your flooring supplier. In poorly insulated rooms, consider a floor sensor to protect the finish.

Floating floors only, and no thermostat included

These panels are for floating, interlocking floor finishes only: wood, laminate, engineered timber and click-lock LVT/SPC. They are not for bonded tile, vinyl or carpet, which need a bonded panel system. No thermostat, wiring centre or actuators are included. Add a room thermostat for each zone you want to control, plus a wiring centre and manifold actuators if each room needs independent control.

Ground floors need extra insulation

On ground-floor concrete slabs, additional insulation beneath the panels is strongly recommended to reduce downward heat loss, with a polythene vapour barrier laid first. Over upper floors above heated rooms, the EPS core of the panel may be enough on its own.

Plan your panel layout

Plan the panel layout before you start so the pipe grooves line up across the panel joins and cuts are kept to a minimum. The kit supplies 117 panels to cover 84m² including cuts and offcuts.

Key features

Ultra-low 18mm build height

At just 18mm total depth, the panels sit directly on an existing screed or timber deck, so there is no excavation and very little change to floor level.

Floating, no-adhesive installation

Panels are laid loose with butt joints, with no glue or fixings and the interlocking floor goes straight on top. No curing or drying time.

Foil-faced EPS at 150mm centres

A metallised aluminium foil is bonded to the top of the panel and into the grooves, spreading heat evenly. Each panel has 4 grooves at 150mm centres plus bulb-end returns.

12mm multilayer pipe

560m of 12mm multilayer pipe (PEX-Al-PEX / PERT-Al-PERT) has a tighter bend radius than 16mm pipe, which suits smaller rooms and tight corners, and it stays where you put it.

Grundfos pump and mixing valve

An A-rated Grundfos pump with a thermostatic mixing valve sets the water temperature for the floor, whatever the temperature of the heat source.

7-port stainless steel manifold

Up to 7 separate loops, each with its own connector core, so rooms can be balanced and controlled separately. Tools and connectors are included.

Technical specification

Kit overview

Kit coverage

84m²

Manifold ports (zones)

7

Heating type

Wet (warm water) underfloor heating, overlay system

Thermostat

Not included

Panels

Panel type

18mm foil-faced EPS routed panel, floating floor

Panel size

1200 x 600mm (0.72m² per panel)

Panels supplied

117

Total panel depth

18mm

Surface

Metallised aluminium foil, bonded to top surface and into grooves

Groove layout

4 grooves at 150mm centres, bulb-end returns and 3 straight runs for flow and return

Pipe centres

150mm

Pipe

Pipe type

12mm multilayer pipe (PEX-Al-PEX / PERT-Al-PERT)

Pipe supplied

560m

Connector cores

14

Manifold and pump

Manifold

7-port stainless steel manifold

Circulation pump

A-rated Grundfos pump

Temperature control

Thermostatic mixing valve

Typical working temperature

45-50°C (system guidance)

Installation and floor finish

Installation method

Floating, loose lay with no adhesive or fixings

Suitable floor finishes

Floating interlocking wood, laminate, engineered timber, click-lock LVT/SPC

Not suitable for

Bonded tile, vinyl or carpet finishes

Subfloor

Solid concrete screed or timber floor deck, flat to SR2 (+/-5mm over 2m)

Vapour barrier

Polythene barrier recommended on concrete slabs

Floor laying direction

Lay interlocking floor at 90° to the pipe direction

Perimeter expansion gap

10-15mm

Maximum floor surface temperature

27°C for wood and laminate (confirm with flooring supplier)

Supplied tools

Pipe cutter

Included

Pipe reaming tool

Included

Frequently asked questions

What is included in the 84m² kit?

The kit includes 117 x 18mm foil-faced EPS panels, 560m of 12mm multilayer pipe, a 7-port stainless steel manifold with A-rated Grundfos pump and thermostatic mixing valve, 14 connector cores, and a pipe cutter and reaming tool. No thermostat is included, so you will need to buy a room thermostat for each zone separately.

Which floor finishes can I use with this system?

Use floating, interlocking floor finishes: wood, laminate, engineered timber and click-lock LVT/SPC. The floor is laid over the panels at 90° to the pipe direction. The system is not designed for bonded tile, vinyl or carpet. Those finishes need a bonded panel system.

How is the system installed, and does it need adhesive or screed?

It needs no adhesive, no screed and no fixings. Lay a vapour barrier if you are on concrete, loose-lay the panels with tight butt joints, press the 12mm pipe into the grooves starting from the manifold, then connect, flush, fill and pressure test the pipework. Only after a satisfactory test, lay the interlocking floor, leaving a 10-15mm expansion gap around the room.

Can I connect this kit to a heat pump or a boiler?

Yes. The A-rated Grundfos pump and thermostatic mixing valve let you set the underfloor flow temperature, and normal working temperature is around 45-50°C, which suits low-temperature heat sources as well as boilers. Make sure the heat source is sized for the total heat load of the rooms.

How many rooms or zones can this kit control?

The manifold has 7 ports, so you can connect up to 7 separate loops. Each loop can be balanced at the manifold. For independent room-by-room control, add a thermostat for each zone, a wiring centre and manifold actuators.

What subfloor and insulation do I need?

The subfloor must be solid, stable and flat: a solid concrete screed or a timber floor deck, flat to SR2 (+/-5mm over 2m). On ground-floor slabs, add insulation under the panels and a polythene vapour barrier to cut downward heat loss. Over upper floors above heated rooms, the panel's EPS core may be sufficient.

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Room Dimensions

Length (in m):

Width (in m):

Height (in m):

Room Type

Living Room

Bedroom

Kitchen

Bathroom

Conservatory

Hallway

Glazing Type

Single Glazed

Double Glazed

Triple Glazed

External Walls

0 Wall

1 Wall

2 Walls

3 Walls

4 Walls

Insulation Level

Poor

Average

Good (New Build)

Calculate

Required Heating

0

Watts

0

BTUs