Technical Info

CPS (Closed-Panel, Sigma® II) is a factory-finished double-stud wall with blown-fibre glass wool, service zone and membranes integrated for rapid erection, deep cavities (≈235 mm) and excellent thermal bridge performance. It carries BOPAS+/BBA approval and targets ~0.13–0.15 W/m²K walls.

SIP uses OSB skins around a rigid polyurethane core. Our standard SIP wall build-ups typically achieve ~0.16 W/m²K with additional insulated plasterboard and internal VCL/service battens to match CPS performance.

In practice: CPS reduces follow-on trades (factory-fitted membranes/service cavity) and limits cold bridges; SIP offers fast shell assembly but requires more internal follow-on works to equal CPS fabric levels.

Not by default. We aim for very low energy use via high U-values, airtightness and MVHR, but we don’t certify every home to Passivhaus. Reasons include design freedom (e.g., view-led glazing), site context and client budget. If your brief prioritises PH targets, we can align early on orientation, glazing ratios, thermal bridge details and airtightness testing to approach those metrics.

CPS walls use hydrophobic blown glass-wool in a deep double-stud cavity. Glass-wool is mineral-based (not oil-derived), recyclable, and typically offers lower embodied carbon than PUR/PIR rigid foams—while delivering excellent thermal and acoustic performance.

SIP cores are closed-cell polyurethane; to match CPS U-values they need additional insulated linings and an internal VCL/service zone.

• Walls: CPS ≈0.13–0.15 W/m²K; SIP spec example ~0.16 W/m²K.
• Roof: ~0.12 W/m²K with SIP roof cassettes/insulated build-ups.
• Floor slab: ≈0.15 W/m²K typical build-up.
• Windows: ~1.2 W/m²K double, upgrades to ~0.7 W/m²K triple available.

We detail for low leakage and test to BS EN ISO 9972. Whole-house MVHR is strongly recommended: it recovers heat, filters air, reduces humidity and includes summer bypass and humidity/boost controls. Design and commissioning are by certified installers; controls via panel or app.

ASHP (air-to-water) is our common solution feeding underfloor heating and a hot-water cylinder, with zoning, weather compensation and insulated pipework to BS 5422. Installers are MCS registered; systems are commissioned with handover information. Towel rails/rads supplement wet zones as needed.

Yes—PV is commonly integrated and can be paired with battery storage to reduce grid demand and running costs. MVHR + ASHP + PV is a proven route to low operational energy. (Your energy designer will size arrays and advise export tariffs; we coordinate roof layouts and penetrations.)

High-performance timber frames with optional aluminium cladding for durability in exposed sites; standard finishes (e.g., RAL7016) with alternative colours at no cost change. Upgrades include triple glazing (~0.7 W/m²K) and solar-reflective coatings for south-facing areas.

Roofs: standing-seam aluminium or slate, both detailed to relevant British Standards and good practice guides; correct fixings, ventilation and flashings are essential.

Walls: timber rainscreen or render over block. Timber (open or closed joints) weathers to a silver tone with minimal maintenance if left untreated.

Partitions include acoustic rolls; floors receive acoustic insulation; lining and roof/partition build-ups use rated boards (e.g., 15 mm plasterboard ceilings). Integrated, mains-linked smoke/heat/CO alarms are installed and certified to current British Standards.

Drainage is designed/installed to the relevant BS/EN standards with rodding access and AAVs as required. We specify water-efficient fittings (e.g., 4.5 L average dual-flush WCs, 6 L/min basin taps) and scald-protection via thermostatic mixing valves; unvented cylinders are installed/labelled by a competent person.

• Timber structure with high pre-manufactured value cuts waste and sequesters carbon.
• CPS insulation is mineral glass-wool (not oil-based), with deep cavities for low U-values without heavy foam reliance.
• Low energy systems: ASHP + MVHR + PV options minimise operational energy; controls and zoning further reduce demand.
• Quality assurance: BOPAS+/BBA approvals and air-testing help ensure long-term performance.

CPS (Sigma® II) holds BOPAS+ and BBA approvals; our builds proceed with a recognised 10-year structural warranty and statutory compliance. Many lenders are familiar with our systems and stage-payment approach.

SIP wall (example): insulated plasterboard + service void + internal VCL, 150 mm SIP, external breather + battens + timber cladding  →  ~0.16 W/m²K.

SIP roof (example): standing-seam metal on plywood & battens + underlay + 175 mm SIP + internal VCL + service void + insulated plasterboard  →  ~0.12 W/m²K.