AD-SLIM grooved gypsum overlay board with warm-water heating pipe

Water underfloor heating solution

AD-SLIM Low-Profile Overlay System

A compact warm-water solution for renovations, extensions and existing floors.

AD-SLIM uses an 18mm grooved high-density gypsum board to position 12mm PERT heating pipe at consistent 150mm centres. It creates a dry overlay build-up over a suitable existing floor without requiring a traditional full screed layer.

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The system behind the solution

Choose Your AD-SLIM Kit

Grooved high-density panels hold 12mm pipe in a compact retrofit system. Pick a standard kit or ask us to plan the complete floor height.

Adept AD-SLIM kit showing grooved boards, heating pipe, manifold, pump and fittings
A compact retrofit system

Grooved panels, pipe and controls vary by kit size.

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Choose a standard kit

Select the heated area that matches your project.

Kit size

12m² kit contents vary by size. Review the full kit details before ordering.

Selected kit
£866.49 inc. VAT
Unsure of the right size or zoning? See full kit contents and specifications

Not Sure Whether AD-SLIM Suits Your Floor?

Tell us about the existing base, available floor height, room plans, heat source and intended finish. Our specialists can help confirm the system and complete build-up.

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AD-SLIM grooved gypsum boards laid across an existing floor

Straightforward installation

How AD-SLIM Is Installed

Plan the board layout and heating circuits together before installation. For manifold connections, testing and commissioning, read our water installation guide alongside the AD-SLIM system instructions.

  1. 1Confirm that the existing base is sound, clean, level and structurally suitable
  2. 2Plan the board layout, heating circuits and manifold connections
  3. 3Fix the AD-SLIM boards using the preparation and fixing method specified for the base
  4. 4Press the 12mm PERT heating pipe into the grooves, connect the circuits and complete pressure testing
  5. 5Install the required preparation or overboarding layer before the approved finished floor
AD-SLIM grooved gypsum board showing the heating pipe route

Designed as one floor layer

Why the Gypsum Board Matters

A dry-board construction can make adding underfloor heating more practical when a traditional full screed would be too deep.

  • A dense, stable dry-overlay layer over a suitable structural base
  • Grooved boards make the planned pipe layout easier to follow
  • No traditional full screed layer; any finishing compound still needs its specified curing time

Plan the complete installation

Where AD-SLIM Works Best

AD-SLIM is designed for renovation, extension and retrofit projects over a suitable existing floor. The existing base must be sound, clean, level and structurally suitable.

  • Sound solid or screeded floors
  • Suitable beam-and-block floors
  • Structurally suitable suspended timber floors
  • Suitable battened floor constructions
Exploded concept view of a typical AD-SLIM floor build-up

Typical Floor Build-Up

Allow for every layer when checking the finished height—not just the 18mm board.

  1. 1Prepared, sound and level structural base
  2. 2Specified fixing materials and any supporting layers
  3. 318mm grooved AD-SLIM gypsum board
  4. 412mm PERT pipe within the grooves
  5. 5Approved floor finish and any required overboard or levelling layer
18mm
Grooved gypsum board thickness
12mm
PERT heating pipe
150mm
Pipe centres
1200 × 600mm
Board size

AD-SLIM project advice

Frequently Asked Questions

Clear answers about board height, suitable floors, floor finishes and planning an AD-SLIM installation.

What is the AD-SLIM underfloor heating system?

AD-SLIM is a compact warm-water overlay system using an 18mm grooved high-density gypsum board and 12mm PERT heating pipe. It is designed to add underfloor heating over a suitable existing floor without a traditional full screed layer.

How much floor height does AD-SLIM add?

The AD-SLIM board is 18mm thick, but the total floor build-up is greater than the board alone. Preparation, fixing materials, supporting or levelling layers and the final floor finish must all be included when checking the completed height.

Which floor constructions can AD-SLIM be installed over?

AD-SLIM can be considered over suitable solid or screeded floors, beam-and-block floors, suspended timber floors and battened floors. In every case, the existing base must be sound, clean, level and structurally suitable for the specified build-up.

Which floor finishes can be used over AD-SLIM?

Compatible tile, engineered wood, vinyl and carpet finishes can form part of an AD-SLIM installation. The required preparation layer varies by finish, and both the heating-system and floor-covering manufacturers’ requirements must be followed.

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Can tiles or engineered wood be installed directly?

Tiles and compatible engineered wood may potentially be installed directly when the relevant AD-SLIM system guidance and floor-manufacturer requirements permit it. Confirm the fixing materials, temperature limits and complete build-up before installation.

What is required beneath vinyl or carpet?

Vinyl and carpet require overboarding with a minimum of 6mm plywood. Alternatively, a suitable 5mm latex self-levelling compound can be used. Confirm compatibility, curing, adhesives and floor-temperature limits for the selected covering.

What condition must the existing floor be in?

The existing base must be sound, clean, level and structurally suitable. Any movement, contamination, unevenness or weakness must be addressed using the preparation and fixing method specified for the floor construction.

How do I choose the correct AD-SLIM kit?

Provide the room dimensions, usable heated area, floor construction, heat source and intended finish. A project design should confirm pipe circuits, manifold and control requirements, and the correct kit before ordering.