The Warmup Ultralight UFH Insulation Board is a 4-in-1 composite underfloor heating board that delivers insulation, heat spreading, decoupling, and acoustic performance in a single 6 mm sheet. Designed specifically for use beneath electric UFH systems such as the DCM-PRO loose-lay cable and StickyMat, it cuts heat-up times by up to 78% and reduces running energy by up to 71% compared to installing on uninsulated concrete — turning a two-and-a-half hour warm-up into under 30 minutes. At just 1.145 kg/m², it is far lighter than cement-based boards and won't crack if dropped or bent.

78%

Faster Heat-Up

71%

Energy Saving

6 mm

Total Thickness

1.1 kg

Per Board

10 yr

Warranty

ℹ️ Tip: Using Warmup Ultralight boards with the DCM-PRO Peel-and-Stick membrane gives the optimal combination: boards provide a perfectly flat, insulated surface for the self-adhesive mat to bond to — no SBR primer required in this case.

⚠️ Note: Warmup Ultralight boards carry a Fire Rating of E. They must be covered with tile adhesive, self-levelling compound, or the floor finish immediately after the heating system is installed — do not leave boards exposed. Multiple boards must not be stacked on top of each other.

Key Features

🔥 Aluminium Heat-Spreading Layer

An aluminium foil layer within the board construction conducts heat laterally and evenly across the floor surface, eliminating hot and cold spots and ensuring that the full heated area reaches temperature uniformly.

🧊 PEF Insulation Core

The polyethylene foam (PEF) core reflects heat upward rather than allowing it to dissipate into the subfloor — the single most effective change you can make to reduce running costs and warm-up times with electric UFH.

🛡️ Decoupling Bottom Fleece

A non-woven decoupling fleece on the underside absorbs differential movement between the subfloor and the finished floor, protecting tiles and stone from cracking due to seasonal expansion and contraction.

🔊 Intertek-Tested Acoustics

Acoustic performance has been independently tested by Intertek and found to be comparable with dedicated rubber, cork, or foam acoustic products — making this board a true 4-in-1 solution for residential and light commercial floors.

💧 Water & Mould Resistant

The composite construction is fully water and mould resistant, making the boards ideal for bathrooms, kitchens, and other wet areas where cement-based boards are traditionally used but add significant weight and installation complexity.

⚖️ Ultra-Lightweight

At 1.145 kg/m² — a fraction of the weight of cement-based tile backer boards — Warmup Ultralight boards are easy to carry, cut with a utility knife, and position. They will not snap under normal handling, even if flexed.

Board Layer Construction

From top to bottom, each board comprises four bonded layers:

① Top Non-Woven Fleece — direct adhesion surface for heating system

② Aluminium Heat-Spreading Layer — even heat distribution

③ PEF Insulation Core — thermal reflection upward

④ Bottom Decoupling Fleece — movement absorption, mortar bond

Technical Specifications

Property	Value
Model / SKU	WCI (single: WCI-01; pack of 6: WCI-06; pack of 16: WCI-16)
Board Dimensions	1200 mm × 800 mm × 6 mm
Coverage per Board	0.96 m²
Weight per Board	1.1 kg (2.43 lb)
Weight per m²	1.145 kg/m²
Thermal Resistance (RSI)	0.111 m²K/W
R-Value (Imperial)	0.630 °F·ft²·h/BTU
Thermal Conductivity	0.054 W/mK
Compressive Strength (10% compression)	32 psi (220 kPa)
Fire Rating	E
Acoustic Testing Body	Intertek
Compatible UFH Systems	Warmup DCM-PRO, StickyMat, Foil Heater
Max Self-Levelling Compound Depth	3/8 in (approx. 10 mm)
Warranty	10 years

Available Pack Sizes

SKU	Pack Contents	Total Coverage
WCI-01	1 board	0.96 m²
WCI-06	6 boards	5.76 m²
WCI-16	16 boards	15.36 m²

Frequently Asked Questions

Why do I need an insulation board under electric underfloor heating?

Without insulation, a significant proportion of the heat generated by the cable or mat is lost downward into the subfloor. Warmup's tests show that warm-up time drops from around 2.5 hours to under 30 minutes with Ultralight boards installed, and energy consumption falls by up to 71% — making insulation one of the highest-value upgrades in any UFH installation.

Are Ultralight boards compatible with the DCM-PRO Peel-and-Stick mat?

Yes, and this is the recommended pairing. The smooth, flat top surface of the Ultralight board is the ideal substrate for the DCM-PRO Peel-and-Stick membrane, and no SBR primer is needed when fixing to the boards — saving time and materials. Simply lay the boards with staggered joints and adhere the DCM-PRO mat directly on top.

How are the boards fixed to the subfloor?

Adhere boards to a clean, flat concrete or timber subfloor using polymer-modified thinset mortar. Stagger the board joints to create a continuous thermal break. Do not layer multiple boards on top of each other. Once fixed, the heating system is installed on top and the whole build-up is covered with tile adhesive, self-levelling compound, or the final floor finish.

Can Ultralight boards be used in wet areas such as bathrooms?

Yes. The boards are water and mould resistant and suitable for bathrooms, en-suites, and kitchens. When used in full wet rooms, ensure that the DCM-PRO Waterproofing Tape is applied over the heating system and membrane seams in accordance with Warmup's installation guide before tiling.

How many boards do I need, and which pack should I order?

Each board covers 0.96 m². Divide your total heated floor area by 0.96, then round up to the nearest board. For most bathroom installations (3–5 m²) the WCI-06 pack of 6 boards is ideal; for larger kitchen or living room projects, the WCI-16 pack of 16 boards (15.36 m²) offers the best value.

Underfloor Heating Insulation