1️⃣ Grooved insulation board
The insulation board is typically EPS or XPS with pre-routed grooves (channels) into which the pipe sits perfectly. These grooves replace the function of the knob plate used in wet-build systems.
Dry-Build Underfloor Heating (No Cement): The solution for renovations and low floor heights
If you are renovating an older home and cannot "lose" 8–10 centimetres of floor height, traditional wet-build underfloor heating simply does not fit. Dry-build systems need only 3 to 5 centimetres, require no thermal screed, and are installed in record time without waiting 28 days for curing.
How does it work? Instead of thermal screed, it uses gypsum fibreboard or plasterboard (dry structural panels) and aluminium heat-spreader plates that dramatically boost performance.
1. How It Works: Layering without water, without cement
Dry-build replaces the thermal screed with a system of dry panels. On top of the insulation (or even on top of an existing floor), specialised insulation boards with grooves are placed into which the pipe snaps together with aluminium heat-spreader plates.
2️⃣ Aluminium heat-spreader plate
Inside each groove, a thin aluminium heat-spreader plate is placed that "hugs" the pipe. The aluminium grabs the heat from the pipe and distributes it evenly across a large surface area.
3️⃣ Gypsum fibreboard
On top of the plates, a gypsum fibreboard (Fermacell) or plasterboard panel is laid. This is the "walking surface" that replaces the thermal screed. Tile, laminate or engineered wood is installed directly on top.
📐 Total thickness
The entire system (insulation + pipe + aluminium + fibreboard) requires only 3 to 5 centimetres - half the thickness of wet-build. Ideal for renovations and rooms with low ceiling height.
2. The Role of Aluminium: Why dry-build fails without it
In wet-build, heat is distributed through the thermal mass of the screed. In dry-build, there is no cement. Without something to replace that role, the heat would remain in a narrow strip above the pipe - creating a terrible "Zebra Effect".
🌡️ Performance boost
The aluminium plate hugs the pipe and dramatically increases thermal conductivity. It converts a narrow heat strip into a large, uniform emission surface - the pipe effectively "sees" a much larger floor area.
⚡ Ultra-fast response
Unlike wet-build (which takes hours), dry-build with aluminium responds in 15–30 minutes. Ideal for homes with irregular occupancy (e.g. an office that cools overnight and needs rapid morning warm-up).
❌ Without aluminium
Some "budget" dry-build systems omit the aluminium plates to cut costs. This may save money on installation, but the heat emission performance drops dramatically, creating uneven floor temperatures.
✅ The right choice
Always choose a system with full-coverage aluminium heat-spreader plates. The plates should cover at least 80% of the floor area for uniform temperature distribution.
3. Advantages & Disadvantages: When dry-build is worthwhile
Dry-build is not "worse" or "better" than wet-build. It is an alternative solution that solves specific problems - primarily in renovation projects. Let us examine where it excels and where it falls short.
✅ Low profile (3–5 cm)
Ideal for renovating older homes where 10 cm of screed does not fit between the floor and the door frame. Also ideal for timber floors (wooden joists) that cannot bear the weight of wet screed.
✅ Zero drying time
No cement is poured, so there is zero waiting. Tiles or laminate can be installed immediately after the fibreboard. Ideal when construction timelines are critical (e.g. hotels).
✅ Lightweight
Dry-build weighs less than half compared to a thermal screed system. A critical advantage in older buildings with weak slabs or timber floor structures.
❌ Lower thermal mass
Dry-build stores less heat compared to the large mass of thermal screed. This means the home cools down faster if the Heat Pump is switched off for an extended period.
❌ Higher material cost
Aluminium plates and gypsum fibreboards cost significantly more than the materials of a traditional wet-build system. The final cost per sqm can be 30–50% higher.
4. Cost Comparison & When to Choose Dry vs Wet Build
The final choice does not depend on cost alone. It depends on three critical factors: available height, floor structural capacity and construction time.
🏗️ New build
In a new home where the architect can design the correct heights from the outset, wet-build wins: cheaper, greater thermal mass, and proven long-term durability.
🔧 Renovation
In an older home with low ceilings, existing doors and timber floors, dry-build is the only realistic option. The 3–5 cm profile fits where 10 cm simply does not.
⏰ Construction time
If you must deliver on a tight schedule (hotels, commercial spaces), dry-build saves 4–6 weeks compared with the curing time of thermal screed.
💰 Cost per sqm
Dry-build costs €55–85/sqm (materials + installation), whereas wet-build costs €35–55/sqm. The gap narrows when you factor in time savings and avoiding changes to doors and ceiling heights.
💡 If you are renovating and your floor height is limited, do not hesitate - dry-build underfloor heating is a reliable, fast and technologically complete solution. Just ensure the installer uses aluminium heat-spreader plates and proper gypsum fibreboard (at least 18 mm thick).
Related Articles
Underfloor Heating Layering: Wet Build Construction Guide Thermal Screed Thickness & Special Additives Expansion Joints in Underfloor Heating Best Floor for Underfloor Heating: Tile, Wood or Laminate
Emission Systems: Underfloor, Fancoils & Radiators
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