Technical Product Description
Last Modified: 13-11-2025
Floor Construction
Casted Lightweight Concrete Floor
Bathroom pods using a casted lightweight concrete floor are constructed in reinforced concrete (C30/37) with an approximate density of 2350 kg/m³. The element is cast with an upstand, and the total floor thickness is 100 mm including flooring but excluding insulation. Drainage and heating installations are embedded in the floor, and floor drains are generally positioned below the bottom edge of the base. Door threshold and transition details to adjacent flooring follow Nordic Offsite’s standard solutions.
The concrete floor is cast with an integrated slope, providing a minimum gradient of 30 mm towards the drain. Any recess required for a shower niche is formed directly into the cast element. Insulation can be incorporated according to individual project requirements.
Steel Profile Floor
Bathroom pods constructed with a steel-profile floor utilise steel C-profiles (75×45×0.9 mm) at a maximum spacing of 300 mm. These profiles are clad with waterproof plywood fastened with screws at a maximum spacing of 200 mm. The full construction, including flooring, achieves an approximate thickness of 107 mm. Shower areas may be constructed using either a shower tray or a built-in shower corner. Drainage and electrical heating installations are embedded within the floor, and insulation can be added based on project requirements.
For a visual reference, see the illustrated cross-section of our standard wall and floor construction here: view Illustration
Wall Construction
Lightweight Concrete Walls
Lightweight concrete walls are cast in reinforced LC20/22 concrete with a density of approximately 1600–1800 kg/m³. Standard wall thickness is 60 mm, with the option to increase to 80 or 100 mm where kitchen units, fire protection, or enhanced acoustic performance are required. Walls are cast individually and assembled into full-height modules.
External visible walls are finished 20 mm above the lower edge of the building’s concrete slab, skimmed, and factory-finished with plaster corner profiles. These additions increase total wall thickness. On-site, external walls must be cleaned, reinforced with mesh at joints, and fully plastered by another contractor. The bottom edge terminates 20 mm above the finished floor level.
Internal walls are delivered either tiled or fully skimmed, lined with fibre lining, and painted white with a gloss level of 20. Two mounting rails are installed within the service shaft area.
Fermacell and Steel Profile Walls
Fermacell-based wall systems consist of 15 mm Fermacell internal panels supported by 75 mm steel profiles at 600 mm centres, producing a total wall thickness of 90 mm. Internal walls may be tiled or fully skimmed and painted white (gloss 20). Two mounting rails are included in the service shaft.
For a visual reference, see the illustrated cross-section of our standard wall and floor construction here: view Illustration
Ceiling Construction
Lightweight Concrete Ceiling
Lightweight concrete ceilings are constructed from reinforced LC20/22 concrete, weighing roughly 1600–1800 kg/m³. The ceiling thickness is 60 mm. The underside is delivered as a smooth cast surface, skimmed, and painted white (gloss level 20).
Fermacell Ceiling
Fermacell ceilings consist of 75 mm steel profiles clad on the interior with 15 mm Fermacell. The completed ceiling thickness is 90 mm. The underside is skimmed and painted white (gloss level 20).
Acoustic Performance
The standard 60 mm wall configuration achieves an airborne sound insulation value of 62 dB, meeting and exceeding the UK Building Regulations requirement of ≥55 dB.
Impact sound insulation calculations achieve ≤40 dB, within the UK Building Regulations requirement of ≤58 dB.
Compliance with UK regulations: Yes for both airborne and impact sound requirements.
Fire Protection
Our bathroom pod wall systems are independently tested by PAVUS (Czech Republic) in accordance with ČSN EN 1364-1 and classified under ČSN EN 13501-2. Both systems comply with stringent fire-separation requirements and demonstrate stable behaviour under standard fire-curve exposure.
The lightweight steel-frame wall with Fermacell sheathing is tested as a non-loadbearing partition using 15 mm Fermacell fibre boards on both faces. The system achieved E 60 / EI 60 / EW 60, maintaining integrity (E), insulation (I), and radiation control (W) for at least 60 minutes. This confirms the system’s suitability as a compliant fire-separating element for bathroom pod applications.
Report: Fire Resistance Classification Report – Lightweight Wall (Fermacell).pdf
The aerated concrete wall construction is tested as a symmetrical non-loadbearing wall with integrated reinforcement. It achieved E 60 / EI 60 / EW 60, demonstrating stable thermal and structural behaviour throughout the full test duration.
Report: Fire Resistance Classification Report – Concrete Wall.pdf
Waterproofing Membrane
A waterproof membrane sealing system is applied in the wet area, covering the floor and extending 200 mm up the walls.
Sealant and Mortar Joints
Mortar joints are applied between wall and floor tiles. Acrylic sealant is used between ceilings and walls. A slanted silicone joint (6–10 mm) with backstop is applied between the floor/skirting and wall tile interfaces.
Electrical Installations
Electrical boxes are embedded within lightweight concrete walls or mounted in Fermacell panel systems. LK is the primary manufacturer used, with Fuga and Opus also available. Conduits are embedded or placed behind Fermacell panels and consist of Ø16 mm or Ø20 mm plastic pipes.
Basic lighting is connected via an external membrane junction box in the shaft and operated through an external switch box using two conduits running to the floor.
Equipotential bonding is provided from the grounding terminal in the shaft to bathroom metal components, fixtures, water fittings, and the ventilation system.
Domestic Water Installations
Water installations use 15 mm PEX pipes housed in 28 mm conduits. Coupling boxes are embedded within wall panels. Vertical water routing connects at the top of the pod to the installation shaft. Each pod includes two distribution manifolds with ¾” male threads in the shaft (or within 3 metres), supplied by insulated PEX (13 mm insulation).
Drainage Installations
Drainage is installed using PEH pipes. Connections from the floor drain, sink, and washing machine are routed as close as possible to the shaft using Ø40/50/75 mm PEH. The primary floor drain is Ø110 mm PEH.
Heating Installations
Casted Concrete Floors
Waterborne underfloor heating uses Ø15 mm PEX pipes supplied as a 3-metre coil system. Pipes are fixed beneath the top reinforcement mesh with approximately 200 mm spacing. If included, regulation/mixing valves are installed per manufacturer specifications; system commissioning is performed by others.
For waterborne systems, the return valve must not exceed 40°C, as higher temperatures may damage tiles or grout.
Steel Profile Floors
Electrical heating mats (100 W/m² @ 230 V~) are used, requiring an additional 5 mm floor build-up.
Ventilation
Exhaust ducts are positioned in the ceiling and routed through a 90° bend with a 40 mm air gap over the pod to the installation shaft. No flexible ducts or bends may be used above the pod.
Door Components
Door frames, door leaves, door architraves, door thresholds, and door fittings are outside the Nordic Offsite delivery scope. For bathroom pods with lightweight concrete walls, nylon mounting blocks are cast into the door opening to facilitate installation of the door frame.
Packaging
Pods are delivered with a protective plywood board over the door opening, removed during installation. The bottom 200 mm of the pod remains uncovered for lifting-point and structural inspection. Protective plastic sheeting covers the pod top to prevent water ingress, and each pod is ID-labelled.
Reference Pod
The first pod produced is fast-tracked as a reference unit. Inspection can be arranged with the Nordic Offsite project manager.
General Standards and Compliance
All production follows industry-standard tolerances, British Standards for plumbing, electrical, and structural work, UK Building Regulations, and relevant manufacturer specifications and certifications.