house-spec/specs/04-flooring-ceiling-spec.md

Flooring & Ceiling Specification — Lindner Raised Floor + Radiant Ceiling

1. Design Philosophy

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.

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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.

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
    H["Floor Pedestals\nadjustable steel"] --> I
    I["Structural Floor Deck / Slab\n+ Radon membrane below"]

    style D fill:#1a5e1a,color:#fff,stroke:#0d3d0d
    style C fill:#8b0000,color:#fff
    style F fill:#1a3d5e,color:#fff

2.1 Height Calculation

Layer	Ground Floor	Upper Floor	Notes
Structural floor-to-floor height	3000-3200 mm	3000-3200 mm	Baufritz to specify; must be ≥ 3000 mm
Structural deck (floor + ceiling)	-200 mm	-200 mm	Timber joists + sheathing
Ceiling system (Plafotherm + suspension)	-80 to -120 mm	-80 to -120 mm	Depends on product variant
Raised floor (cavity + panel + parquet)	-200 to -250 mm	-130 to -170 mm	Ground floor deeper for MVHR ducts
Usable clear height	2430-2720 mm	2510-2790 mm	Target ≥ 2500 mm

2.2 Recommendation

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.

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3. Raised Floor — Lindner NORTEC Doppelboden

3.1 System Overview

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.

Parameter	Value
Product	Lindner NORTEC (Doppelboden / raised access floor)
Panel material	Fibre-reinforced calcium sulphate (CaSO4), up to 100% recycled
Panel dimensions	600 x 600 mm
Panel thickness	40-44 mm
Load class	3-6 (per EN 13213)
Point load capacity	3-7 kN (depending on class)
Fire class	A1 non-combustible (EN 13501-1)
Fire resistance	F30 (DIN 4102-2)
Weight	41-55 kg/m2
Sustainability	Cradle to Cradle Silver certified

3.2 Pedestal System

Parameter	Value
Type	Type S or Type SWH120
Material	Galvanized steel, chrome(VI)-free, zinc-whisker-free
Height adjustment	Infinitely adjustable, 40-2000 mm
Grid spacing	600 x 600 mm
Anchoring	Adhesive bonding only — no mechanical fixings through radon membrane
Approximate quantity	~8 pedestals per m2

3.3 Cavity Height Selection

Zone	Cavity Height	Services Routed	Justification
Ground floor living areas	200 mm	MVHR branch ducts (125-160 mm) + KNX + electrical	Must accommodate duct diameter + clearance
Ground floor kitchen	200 mm	MVHR exhaust branch + electrical + plumbing	Kitchen exhaust duct routing
Ground floor office	150-200 mm	MVHR branch + KNX + Cat6 + electrical	Data-heavy zone
Upper floor bedrooms	100-120 mm	KNX + Cat6 + electrical only	No MVHR ducts (routed in ceiling void)
Upper floor bathrooms	100-120 mm	Electrical + plumbing waste	Waterproof membrane above panels
Technical room	150 mm	Electrical + plumbing connections	Higher load class (Class 5)

3.4 Surface Finish — NORTEC WOODline Parquet

Parameter	Value
Product	Lindner NORTEC WOODline
Material	Solid wood parquet, factory-bonded to panel
Dimensions	600 x 600 x 4 mm
Wood species	Oak, Smoked Oak, Ash Eco, Bamboo Light, Steamed Bamboo
Design patterns	16+ patterns (herringbone, mosaic, 2-strip, geometric, etc.)
Certification	PEFC certified
Joint type	Near-invisible joints with color-matched edge bands
Edge protection	Edge bands extend to parquet top — prevents moisture penetration

Surface Treatment Options

Treatment	Description	Slip Resistance	Best For
Lacquered	6-layer UV curing, matte finish	R9, Class 6 durability	Living areas, kitchen, hallways
Oiled	Hard wax oil, 2 applications, matte	R9	Bedrooms, office
Sanded	Pre-sanded, requires on-site coating	N/A	Not recommended — on-site coating introduces VOCs into sealed envelope

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).

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4. Ceiling Heating/Cooling — Lindner Plafotherm

4.1 Product Selection

Product	Type	Key Feature	Residential Suitability
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)
Heating output (at 15K delta-T)	123 W/m2	149 W/m2	161 W/m2
Cooling output (at 10K delta-T)	-	137 W/m2	159 W/m2
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

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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.

5.2 Revised Air System Architecture

flowchart TD
    MVHR["MVHR Unit\nH13 HEPA filtered supply"] --> TRUNK["Main Supply Trunk\nin ceiling void"]
    TRUNK --> AH1["AirHybrid Panels\nLiving Room"]
    TRUNK --> AH2["AirHybrid Panels\nBedrooms"]
    TRUNK --> AH3["AirHybrid Panels\nOffice"]
    TRUNK --> BATH["Conventional Diffuser\nBathrooms"]

    HP["Heat Pump"] --> MAN["Heating/Cooling Manifold"]
    MAN --> P1["Plafotherm Pipes\nLiving Room"]
    MAN --> P2["Plafotherm Pipes\nBedrooms"]
    MAN --> P3["Plafotherm Pipes\nOffice"]
    MAN --> P4["Plafotherm Pipes\nBathrooms"]

    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

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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)
• KNX bus cable to all room zones
• Cat6a shielded data to all rooms
• Electrical wiring (standard NYM cable)
• Plumbing (where floor-level connections are needed)

Constraints:

• Ducts must be rigid steel/aluminum — no semi-rigid flex except final 0.5 m
• All duct joints mastic-sealed
• Minimum 20 mm clearance between ducts and other services
• No main trunk ducts in the floor cavity — trunk stays in ceiling void. Only branch ducts

6.2 Upper Floor

The upper floor cavity (100-120 mm) accommodates only:

• KNX, Cat6, and electrical wiring
• MVHR ducts route in the ceiling void between floors (same void as Plafotherm)

6.3 Airtightness

The floor cavity must not compromise the house's +3 to +5 Pa positive pressure (see 01-air-system-spec Section 7):

• Panel joints: sealed with Lindner's standard gasket system
• Perimeter: sealed to walls with compressible airtight tape
• Service penetrations: all pipe/cable entries through panels sealed with airtight grommets
• Cavity is NOT ventilated: it is a sealed, conditioned space
• Ducts are individual sealed runs: the cavity itself is not used as an air plenum

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7. Structural and Load Considerations

7.1 Floor Load Classes

Zone	Minimum Load Class	Point Load	Justification
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

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8. Acoustic Performance

8.1 Floor Acoustics

Parameter	Target
Impact sound improvement (delta Lw)	>= 20 dB
Airborne sound insulation (Rw, between floors)	>= 50 dB

• Calcium sulphate panels on rubber-damped pedestals provide acoustic decoupling from the structural floor
• Verify Lindner's acoustic data sheets for the specific pedestal type and cavity height
• Additional acoustic mat between pedestal base plate and subfloor if required to meet targets

8.2 Ceiling Acoustics

• Plafotherm panels provide additional acoustic absorption depending on panel type
• Plafotherm GK HEKDA (plasterboard) offers good mid-frequency absorption
• Metal panels (B/E series) may require acoustic fleece backing for absorption
• Verify weighted sound absorption coefficient (alpha-w) with Lindner

8.3 MVHR Noise in Shared Voids

• Ducts in ceiling void and floor cavity can transmit fan noise between rooms
• Acoustic silencers required at trunk-to-branch junctions and before each distribution point
• Target at all distribution points: < 25 dB(A) (same as 03-baufritz-coordination-spec Section 9.2)
• The AirHybrid panel perforations provide some natural sound attenuation — verify with Lindner acoustic data

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9. Sensor Placement Considerations

9.1 Temperature and Humidity Sensors

With both a heated ceiling above and a raised floor below, the room air temperature gradient is different from conventional construction:

• Mount sensors at 1.2-1.5 m wall height — the midpoint of the room where occupants experience the air
• Away from the heated ceiling: ceiling surface may be 25-35 C — sensors near the ceiling would read high
• Away from the raised floor surface: floor will be at room temperature (no floor heating), but directly above floor diffusers could be cooler
• Away from exterior walls: radiant asymmetry near windows affects readings
• Cross-reference: 02-sensor-automation-spec Section 2.1

9.2 Floor Surface Temperature Sensor

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
• Cross-reference: 02-sensor-automation-spec Section 5.1 (add condensation risk indicator to dashboard)

9.4 Radon Monitoring

• Room-level radon sensor on ground floor (per 02-sensor-automation-spec Section 2)
• 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

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10. Heating/Cooling Control

10.1 Zone Control Architecture

Component	Specification
Flow control	Thermal actuator on manifold, per room/zone
Manifold location	Technical room or dedicated riser closet
Control bus	KNX
Room input	Room thermostat (1.2-1.5 m) + ceiling surface temp sensor
Flow temperature (heating)	30-35 C (outdoor-temperature compensated)
Flow temperature (cooling)	16-18 C (dewpoint-guarded)
Return temperature	25-28 C (heating), 18-20 C (cooling)

10.2 Home Assistant Integration

• Ceiling heating/cooling zones visible on dashboard alongside air quality data
• Floor surface temperature displayed per zone (if floor cooling used)
• Condensation risk indicator: calculated from ceiling surface temp vs. room dewpoint
• Night mode: reduce ceiling temperature setpoint by 2 C (cross-ref 02-sensor-automation-spec Section 4.4)
• Summer cooling: activate when outdoor temp > 26 C and indoor temp > 24 C
• Interlock: dehumidification activates automatically when cooling mode is active

10.3 Condensation Prevention

flowchart TD
    MODE{"Operating Mode?"} -->|Heating| HEAT["Normal Heating\nFlow temp 30-35C"]
    MODE -->|Cooling| COOL["Cooling Active\nFlow temp 16-18C"]
    MODE -->|Off| OFF["Standby"]

    COOL --> DEW{"Ceiling Surface\nvs. Dewpoint?"}
    DEW -->|"> 3K margin"| OK["Safe - Continue Cooling"]
    DEW -->|"2-3K margin"| WARN["Warning\nReduce cooling flow"]
    DEW -->|"< 2K margin"| STOP["STOP Cooling\nActivate dehumidification\nAlert via Home Assistant"]

    style STOP fill:#8b0000,color:#fff
    style WARN fill:#4a4a00,color:#fff
    style OK fill:#1a5e1a,color:#fff

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11. Installation Sequence and Baufritz Coordination

11.1 Pre-Installation Requirements

Prerequisite	Detail
Radon membrane	Installed, sealed, and tested at all penetrations
Structural subfloor	Level to +/- 2 mm per 2 m (Lindner pedestal tolerance)
Structural ceiling deck	Installed with suspension anchor points
Heating manifold	Location fixed, main pipe runs to floor/ceiling entry points
MVHR trunk duct	Installed in ceiling void, branch points identified
Electrical rough-in	Floor-level junction boxes and ceiling-level feeds planned

11.2 Installation Sequence

flowchart TD
    A["1. Install ceiling suspension\nsubstructure from structural deck"] --> B
    B["2. Route Plafotherm heating pipes\nin ceiling void"] --> C
    C["3. Install Plafotherm panels\nonto suspension"] --> D
    D["4. Pressure-test ceiling circuit"] --> E
    E["5. Install floor pedestals\non adhesive pads"] --> F
    F["6. Route services in floor cavity\nMVHR ducts, KNX, Cat6, electrical"] --> G
    G["7. Pressure-test MVHR ducts\nin floor cavity"] --> H
    H["8. Install CaSO4 floor panels\non pedestals"] --> I
    I["9. Seal panel joints and perimeter"] --> J
    J["10. Install WOODline parquet tiles"] --> K
    K["11. Commission heating/cooling\nverify surface temperatures"] --> L
    L["12. Commission MVHR AirHybrid\nverify airflow at ceiling panels"]

    style D fill:#1a5e1a,color:#fff
    style G fill:#1a5e1a,color:#fff
    style K fill:#1a5e5e,color:#fff
    style L fill:#1a5e5e,color:#fff

Key checkpoints (green/teal in diagram):

• Step 4: Ceiling heating circuit pressure test — must pass before panels are closed
• Step 7: Floor cavity MVHR duct pressure test — must pass before panels are installed
• Step 11: Heating/cooling commissioning — verify surface temperatures per zone
• Step 12: MVHR AirHybrid commissioning — verify supply airflow through ceiling panels

11.3 Timeline Integration with Baufritz

Baufritz Phase	Lindner Floor Action	Lindner Ceiling Action
Initial design	Confirm raised floor, specify cavity heights	Confirm Plafotherm variant, specify system depth
Detailed planning	Lindner layout drawings, coordinate with MVHR exhaust	Lindner layout drawings, coordinate with MVHR supply
Pre-fabrication	Verify subfloor level tolerance in prefab panels	Verify ceiling anchor points in prefab panels
Factory build	No impact (floor installed on-site)	No impact (ceiling installed on-site)
On-site assembly	After structure complete	After structure, before floor
Finishing	Parquet tile installation	Final panel fitting
Handover	Floor inspection, service access verification	Heating/cooling commissioning, AirHybrid airflow test

11.4 Lindner Coordination

Both floor and ceiling are from the same supplier — coordinate as a single package:

• Combined layout drawings: floor panel grid, ceiling panel grid, and services routing in a single coordinated plan
• Shared manifold design: heating/cooling manifold serves ceiling circuits (and optionally floor circuits if future floor heating is desired)
• Single procurement: order floor and ceiling systems together — potential cost advantage and guaranteed compatibility
• Lead time: Lindner products are project-manufactured — typically 6-8 weeks from order. Layout drawings must be finalized before ordering.

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12. Cost and Material Quantities

12.1 Estimated Quantities (for ~175 m2 per floor)

Item	Quantity (approx.)	Unit
NORTEC Doppelboden panels	~490	600x600 mm panels per floor
WOODline parquet tiles	~490	600x600x4 mm tiles per floor
Pedestals (Type S/SWH120)	~1,400	Per floor (~8/m2)
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