This house uses a **dual Lindner system**: a raised floor (Doppelboden) below and radiant ceiling panels above. Together they replace traditional screed, radiators, and conventional ceiling finishes with a fully integrated, modular, dry-construction approach.
- **Raised floor** = services distribution layer. The cavity beneath the panels routes MVHR branch ducts, KNX bus cable, Cat6 data, electrical wiring, and plumbing — all accessible by lifting individual tiles.
- **Radiant ceiling** = heating, cooling, and ventilation air distribution. Lindner Plafotherm AirHybrid panels combine radiant water-based climate control with MVHR supply air distribution through ceiling perforations.
- **No wet trades**: Both systems are dry-installed — no screed, no drying time. Ideal for Baufritz timber-frame prefabrication.
- **Lifetime maintainability**: Every component is demountable. A pipe leak, a rewiring job, or a technology upgrade requires lifting tiles or removing ceiling panels — not demolition.
**The raised floor is not a cosmetic choice. It is a services distribution layer that provides lifetime maintainability. The radiant ceiling is not a luxury — it is the most responsive, furniture-independent, and efficient way to heat and cool a sealed, high-performance home.**
---
## 2. Room Height Budget
Both systems consume vertical space. The usable clear room height must be carefully planned with Baufritz at the structural design stage.
```mermaid
flowchart TD
A["Structural Ceiling Deck\n~200 mm timber construction"] --> B
B["Plafotherm Suspension\n30-70 mm substructure"] --> C
C["Plafotherm Ceiling Panel\n30-50 mm radiant panel + pipes"] --> D
D["USABLE ROOM HEIGHT\nTarget: 2500 mm minimum"] --> E
E["WOODline Parquet\n4 mm solid wood"] --> F
F["CaSO4 Floor Panel\n40-44 mm calcium sulphate"] --> G
G["Services Cavity\n80-200 mm depending on floor"] --> H
**Baufritz structural floor-to-floor height must be ≥ 3000 mm**, preferably 3100-3200 mm, to guarantee ≥ 2500 mm usable room height on all floors after both Lindner systems are installed. This must be specified at the initial design stage — it cannot be changed after prefabrication begins.
**Note**: The 316L stainless steel water supply pipes (28 mm OD + 13 mm insulation = ~54 mm total) fit within the existing 300 mm ceiling void allocation alongside MVHR trunk and Plafotherm pipes. No change to the room height budget is required. See 05-water-system-spec Section 6.2.
**Note**: The Lindner raised floor and Plafotherm ceiling systems apply to the ground floor and upper floor only. The cellar/basement is reinforced concrete with direct floor finish — no raised floor or radiant ceiling in the datacenter (see 06-datacenter-spec Section 2).
Since heating is provided by the ceiling system, the raised floor uses **standard NORTEC Doppelboden panels** (not the "comfort" variant with integrated heating pipes). The Doppelboden (raised floor) system uses individually removable modular panels on height-adjustable pedestals — any panel can be lifted at any time for full access to the services cavity below. This is the key advantage over Hohlboden (hollow floor) systems, which form a continuous layer with limited access.
**Recommendation**: Lacquered Oak for main living areas (durability, low maintenance). Oiled Oak for bedrooms (natural feel). **Avoid sanded finish** — on-site coating releases VOCs that conflict with the air quality targets in 01-air-system-spec Section 8 (formaldehyde target < 30 ug/m3).
| **Plafotherm AirHybrid** | Hybrid radiant + ventilation | Combines heating/cooling with MVHR supply air distribution | **Recommended** — eliminates separate diffusers |
| Plafotherm GK HEKDA | Plasterboard radiant ceiling | Seamless plastered finish, residential aesthetic | Good alternative for rooms without MVHR supply |
| Plafotherm E 210 | Hook-on metal ceiling | Clean metal panel look, butt joints | Modern aesthetic option |
| Plafotherm B 100 | Post cap metal ceiling | Cost-effective, visible linear joints | Budget option |
**Primary recommendation: Plafotherm AirHybrid** for all rooms with MVHR supply air. Plafotherm GK HEKDA for bathrooms and rooms where a seamless plastered ceiling is preferred.
### 4.2 Heating/Cooling Performance
| Parameter | Standard Radiant | AirHybrid (2x air exchange) | AirHybrid (6x air exchange) |
| Standard (EN 14037 / EN 14240) | EN 14037 | EN 14037 / EN 14240 | EN 14037 / EN 14240 |
**For context**: A Passivhaus-level Baufritz home has a peak heating demand of approximately 10-15 W/m2. Even the standard radiant panel at 123 W/m2 provides **8-12x the required capacity**. This means only a fraction of the ceiling area needs to be active at any time, or flow temperatures can be very low (maximizing heat pump COP).
### 4.3 Pipe Specifications
| Parameter | Value |
|-----------|-------|
| Connection hoses | PlafoTube PK |
| Nominal width | DN 13 |
| Press coupling | 12 mm brass fittings |
| Pressure rating | 16 bar |
| Flow temperature (heating) | 30-35 C design (low-temp for heat pump efficiency) |
| Flow temperature (cooling) | 16-18 C (must stay above dewpoint) |
### 4.4 System Depth
| Component | Depth |
|-----------|-------|
| Panel (Plafotherm B/E) | 30-50 mm |
| Suspension substructure | 30-70 mm |
| **Total system depth** | **60-120 mm** |
The exact depth depends on the chosen product variant and must be confirmed with Lindner for the specific ceiling type. The AirHybrid variant may require slightly more depth for the ventilation hood on the rear side.
### 4.5 Advantages Over Floor Heating
| Aspect | Ceiling Heating | Floor Heating |
|--------|----------------|---------------|
| Response time | Fast — low thermal inertia | Slow — 5+ hours typical |
| Heat output | ~175 W/m2 max | ~65 W/m2 limited by covering |
| Furniture impact | Zero — completely unobstructed | Significant — rugs and furniture reduce output |
| Floor covering freedom | Any covering, any time | Covering thermal resistance limits options |
| Dust circulation | None — radiant, no convection | Minimal but present |
| Cooling capability | Excellent — natural convection aids cooling from above | Limited — cool air at floor stays at floor |
| Relative cost | ~50% of floor system cost | Baseline |
---
## 5. MVHR Integration via AirHybrid Ceiling
### 5.1 Supply Air Distribution
The Plafotherm AirHybrid integrates MVHR supply air distribution directly into the ceiling panels:
- Ventilation hood mounted on the rear (upper) side of the panel — invisible from below
- Supply air distributed through **panel perforations and induction outlets**
- Even air distribution without perceptible drafts
- **Replaces conventional wall/ceiling diffusers** in rooms where AirHybrid is installed
This means the MVHR supply air is tempered by the radiant ceiling before entering the room — pre-heated in winter, pre-cooled in summer. No cold-air draft sensation.
EX1["Exhaust Grilles\nall rooms"] --> EXDUCT["Exhaust Ducts\nin floor cavity or walls"]
EXDUCT --> MVHR
style MVHR fill:#1a3d5e,color:#fff
style HP fill:#8b0000,color:#fff
style AH1 fill:#1a5e5e,color:#fff
style AH2 fill:#1a5e5e,color:#fff
style AH3 fill:#1a5e5e,color:#fff
```
### 5.3 Humidity Control for Cooling Mode
**Critical requirement**: When the ceiling operates in cooling mode, the ceiling surface temperature drops. If it falls below the room air dewpoint, condensation forms on the panels.
- The MVHR system must control absolute humidity of supply air (see 01-air-system-spec Section 5, steam humidifier / dehumidification)
- Ceiling surface temperature sensors must be installed (see Section 9.3)
- Automated interlock: if ceiling surface temperature approaches dewpoint within 2K, reduce cooling water flow or activate dehumidification
- Cooling water flow temperature must never go below 16 C without verified dewpoint margin
### 5.4 MVHR Duct Routing Revision
With AirHybrid ceiling integration, the duct routing changes:
| Duct Function | Routing Location | Notes |
|--------------|-----------------|-------|
| Main supply trunk | Ceiling void (alongside Plafotherm pipes) | Shared space — coordinate routing |
| Supply branches | Via AirHybrid ceiling panels | No separate diffusers needed |
| Main exhaust trunk | Ceiling void or floor cavity | Depends on building layout |
| Exhaust branches | Floor cavity (ground floor) or wall ducts | Exhaust grilles at low level preferred |
| Kitchen exhaust | Dedicated separate stack | Never through MVHR — unchanged |
---
## 6. Floor Cavity Services Integration
### 6.1 Ground Floor
The ground floor raised floor cavity (200 mm) accommodates:
- **MVHR exhaust branch ducts** (125-160 mm diameter, rigid steel/aluminum per 01-air-system-spec Section 6.2)
- **Drain/waste pipes** (PP push-fit, 40-110 mm — gravity-dependent, see 05-water-system-spec Section 7)
- **Plumbing connections** (where floor-level fixture connections are needed)
**Note**: Water supply pipes (hot + cold) run in the **ceiling void**, not the floor cavity. They are routed alongside the MVHR trunk and Plafotherm pipes, accessible by removing ceiling panels. See 05-water-system-spec Section 6.
**Note**: Fiber backbone (12-core OS2 single-mode) and Cat6a structured cabling risers from the cellar datacenter enter the ground floor through dedicated cable risers and distribute through the Doppelboden cavity. See 06-datacenter-spec Section 6.2.
| Living areas | Class 3 | 3 kN | Residential furniture, foot traffic |
| Kitchen | Class 4 | 4 kN | Heavy appliances |
| Technical room | Class 5 | 5 kN | MVHR unit, humidifier, control cabinets |
| Bathrooms | Class 3 | 3 kN | With waterproofing layer above panels |
| Hallways / stairs landing | Class 3 | 3 kN | Standard residential |
### 7.2 Ceiling Suspension Load
- Plafotherm system weight: approximately 14-16 kg/m2 (without fixtures)
- Baufritz ceiling deck (timber joists + sheathing) must support this additional suspended load
- Verify with Baufritz structural engineer — this is within normal limits for timber-frame construction
### 7.3 Combined Dead Load
| Component | Load (kg/m2) |
|-----------|-------------|
| Raised floor (panels + pedestals) | 41-55 |
| Parquet finish | ~4 |
| Ceiling system (Plafotherm + suspension) | 14-16 |
| **Total additional dead load per floor** | **59-75** |
Baufritz structural engineer must verify that the timber floor deck supports this additional dead load plus the design live load (1.5-2.0 kN/m2 residential per DIN EN 1991-1-1).
### 7.4 Bathroom Considerations
- Calcium sulphate panels are **not inherently waterproof**
- Bathrooms require a **waterproof membrane above the panels** (liquid-applied or sheet membrane)
- Confirm with Lindner whether moisture-resistant panel variants are available
- Pedestal corrosion: galvanized steel pedestals tolerate occasional moisture but are not rated for continuous wet conditions
- Floor drains penetrate through panels — connections sealed with waterproof flanges
- Ceiling panels in bathrooms: use moisture-resistant Plafotherm variant or Plafotherm GK with moisture-rated plasterboard
### 7.5 Pedestal Anchoring
- Pedestals bonded to structural subfloor with **adhesive only**
- **No mechanical fixings through the radon membrane** (see 03-baufritz-coordination-spec Section 4.2)
- Verify adhesive compatibility with radon membrane material (HDPE or bituminous)
- Adhesive must maintain bond under the combined dead load + live load
If floor cooling is used in summer (optional — primary cooling is from ceiling):
- Embedded sensors in or on the parquet surface, 2-3 per zone
- Floor surface must not exceed 29 C (DIN EN 1264 comfort limit for habitable rooms) or drop below dewpoint in cooling mode
### 9.3 Ceiling Surface Temperature Sensor
**Critical for condensation prevention in cooling mode**:
- Embedded sensors on or in the Plafotherm panels, minimum 1 per zone
- Connected to KNX / Home Assistant
- Automated interlock: if ceiling surface temperature approaches room dewpoint within 2K, the system must either reduce cooling water flow or activate dehumidification
- **Additional**: one radon sensor with sampling port into the floor cavity itself — early warning of radon membrane breach
- If cavity radon levels rise while room levels remain normal, the membrane and cavity sealing are working; if room levels rise, investigate immediately
---
## 10. Heating/Cooling Control
### 10.1 Zone Control Architecture
| Component | Specification |
|-----------|--------------|
| Flow control | Thermal actuator on manifold, per room/zone |
| Plafotherm ceiling panels | ~350-450 | Per floor (varies by panel size) |
| Ceiling suspension profiles | As per Lindner layout | Metres |
| PlafoTube heating pipe | ~1,200-1,800 m | Per floor (depends on coverage %) |
| Manifold stations | 1-2 per floor | |
### 12.2 Lead Times and Ordering
- Lindner products are **project-manufactured** — not off-the-shelf
- Lead time: typically **6-8 weeks** from confirmed order
- Layout drawings must be finalized and approved before ordering
- Panels are manufactured to the specific floor plan — changes after manufacturing are costly
- **Coordinate ordering with Baufritz on-site assembly schedule** — panels must arrive after structure is weathertight but before interior finishing begins
