System Overview

The RCP (Ribbed Composite Panel) system is a two-component structural system for single-storey residential construction:

  • Component One: The RCP wall panel — EPAL Euro pallets as the ribbed core, OSB sheathing as structural faces, blown rockwool insulation filling the voids
  • Component Two: CE-marked engineered I-joists spanning floor and roof, supported by standard 2×6 timber joists on earth screws

The complete structural shell — earth screws, wall panels, roof, insulation, windows and doors — costs approximately €15,000–€18,000 in materials. Less than the VAT alone on a conventional build.

The Ribbed Composite Panel

What It Is

The RCP is a site-fabricated structural insulated panel using EPAL Euro pallets as the internal ribbed core. Two layers of 12mm OSB form the structural faces. The pallet structure provides:

  • Structural depth: 145mm (single) or 290mm (double wall)
  • Composite action: OSB faces bonded to timber core create a structural diaphragm
  • Insulation cavity: Void spaces filled with blown rockwool or hempcrete
  • Dimensional standardisation: 1200mm × 800mm modules (EPAL standard)

Materials per Panel

  • 1× EPAL Euro pallet (certified softwood, heat-treated)
  • 2× 1200mm × 800mm × 12mm OSB sheets
  • PU construction adhesive (full-coverage bond)
  • 60mm rockwool batts or blown insulation
  • 4× M8 threaded rods (panel-to-panel connection)

Structural Performance

The RCP panel operating at single-storey height carries well under 10% of its theoretical compression capacity. The system is structurally overengineered by a factor of approximately 200× for single-storey domestic construction.

PropertySingle RCPDouble RCP
Thickness145mm290mm
U-Value0.39–0.42 W/m²K0.21–0.23 W/m²K
Compression capacity>200× design load>400× design load
Weight~22 kg~44 kg

Foundation

Earth Screws (Default)

The default foundation uses helical earth screws — steel piles screwed into the ground using a handheld machine. No excavation. No concrete. No curing time. Removable and reusable.

  • Standard: 4× 1.5m earth screws per wall panel point
  • Load capacity: >20kN per screw in typical Algarve soil
  • Installation: 2 people, 1 day for complete foundation
  • Cost: approximately €800–€1,200 for 80m² house

The Foundation Spectrum

Every decision is a spectrum. The system accommodates:

  • Loose pallets on flat ground: Festival structure, no permit needed
  • Earth screws: Default — demountable, no concrete
  • Pad footings on bedrock: Where screws cannot penetrate
  • Concrete slab: Where full planning permission requires it
  • Basement (Concrete Oreo): Concrete box with RCP superstructure above

Roof System

The roof uses CE-marked engineered I-joists spanning wall-to-wall. STEICO or equivalent I-joists at 600mm centres support:

  • 22mm OSB roof deck
  • Breather membrane + counter battens
  • Solar PV mounting (integrated)
  • Up to 2.5kN/m² snow load (5× Algarve requirement)

Span tables: 400mm depth I-joists span 7.5m at 600mm centres with L/480 deflection limit — well within serviceability requirements.

Off-Grid Package

The default build includes complete off-grid infrastructure:

  • Electricity: 4kWp solar PV array + 10kWh lithium battery + 3kW inverter
  • Hot water: 200-litre thermosiphon solar hot water (80%+ annual demand)
  • Heating: Sand battery (thermal mass) + small wood stove backup
  • Cooling: Canadian well (geothermal cooling tube) — no AC needed
  • Water: Rainwater harvesting + 5,000-litre storage + filtration
  • Waste: Composting toilet (Separett Villa) or septic tank

Total off-grid package cost: approximately €8,000–€12,000 depending on specifications.

Cost Analysis

Shell A — 37.5m² Starter Home (7.5m × 5m)

ComponentCost (€)
Earth screws + timber floor joists1,200
Wall RCP panels (78 panels)2,600
Roof I-joists + OSB deck2,800
Insulation (rockwool, blown)1,800
Windows + doors3,500
Exterior finish (pine tar, cladding)1,200
Interior finish (OSB + paint)800
Off-grid package8,000
Fixings, adhesives, tools1,500
Contingency (10%)2,300
TOTAL€25,700

Shell B — 84m² Family Home (7.5m × 11.25m)

ComponentCost (€)
Complete structural shell18,000
Off-grid package (upgraded)12,000
Interior finishes (higher spec)4,000
Fixings, adhesives, tools2,500
Contingency (10%)3,650
TOTAL€40,150

Performance

Thermal

  • Single RCP wall (145mm): U-value 0.39–0.42 W/m²K — 4–5× better than standard Portuguese masonry (1.8 W/m²K)
  • Double RCP wall (290mm): U-value 0.21–0.23 W/m²K — Passive House territory
  • Heating demand: Estimated 15–25 kWh/m²/year (Passive House range for Algarve climate)

Structural

  • Dead load: ~1.2 kN/m² (roof + ceiling)
  • Live load: 1.5 kN/m² (Eurocode residential)
  • Wind load: 0.6 kN/m² (Algarve, terrain category II)
  • Snow load: 0.3 kN/m² (Algarve — essentially zero)
  • Wall panel capacity: >200× design compression load

Fire Strategy

The RCP system uses a four-layer fire strategy:

  1. Ignition resistance: Exterior OSB protected by pine tar or cladding
  2. Flame spread limitation: Rockwool insulation is non-combustible (A1 rating)
  3. Structural protection: Thick timber sections char slowly (0.65mm/min per Eurocode 5)
  4. Compartmentation: Small rooms, limited fire load, openable windows for egress

The principal fire risk in single-storey timber housing is not structural collapse — it is ignition of contents. The RCP system addresses this through compartmentation and rapid egress, not through exotic fireproofing.

Assembly Protocol

The Three-Team Build

Assembly follows a three-team parallel workflow:

  • Team A — Fabrication: Pre-cuts panels, prepares components, manages the "factory" area
  • Team B — Assembly: Erects walls, installs roof, works from the build protocol sheet
  • Team C — Services: Installs electrics, plumbing, insulation, windows as walls go up

With 8–12 people organised into three teams, the complete weathertight shell is achieved in 5–7 days. Interior finishing and services take a further 3–7 days.

The Build Site

All material arrives on a standard rental flatbed trailer (€80/day, standard driving licence). A family of four unloads everything in one hour. Assembly begins immediately. No crane. No scaffolding beyond simple trestles. No specialist equipment beyond a nail gun, circular saw, drill, and level.