Our System


The Beattie Passive system achieves superior levels of energy efficiency when compared to traditional methods of construction. Our innovative build system performs beyond Passivhaus standards and boasts a whole host of additional benefits, including flood, fire and radon protection.
Learn more about the technical specifications of our Passivhaus certified build system
Made In The UK

The Beattie Passive build system explained

Designed in the Passivhaus Planning Package (PHPP) and constructed around a sustainable timber frame, our Passivhaus certified build system maximises airtightness and eliminates thermal bridging to create an extremely energy efficient structural thermal envelope.

Simplifying Passivhaus

Our build system differs slightly depending on the method of delivery you choose. There are some real advantages associated with going modular, but we appreciate the fact that it’s not always feasible for various reasons. We also understand that each project is unique, so we don’t offer a one size fits all solution. Our team can design and build in a multitude of ways, so let’s have a chat and see what’s right for you.

Wall system

The wall system is always the same regardless of which delivery method you choose.

High performance walls

The wall and roof is constructed with 300mm deep twin studwork. The system is pumped with insulation beads to provide a continuous insulated layer.

Internal walls

The airtightness layer is applied to the inner face of the structural frame and the frame is protected with 9mm fire and racking board. An internal service void is created with 25mm batten to enable easy access to services around the building.

External walls

On the external face of the structural frame, another layer of 9mm fire and racking board is fixed. Breather membrane is wrapped around the building and a 25mm batten is applied to provide a suitable substrate for any external finish and a drained and ventilated cavity. Our system provides complete flexibility for external finishes (such as render carrier board, brick slip carrier board, timber cladding, or full brickwork, amongst others).

Roof system

The roof system (whether cold or warm roof) is exactly the same construction as the walls, delivering a very high u-value and continuous insulation. However, there are some subtle differences between our on-site build system and our modular build system, as shown below.

Modular build system (roof detail)

On-site build system (roof detail)

Ground floor system

Like the roof system, there are some key differences in the modular ground system. Let’s take a look at the modular system first and then explore the on-site system. We’re always more than happy to explain the technicalities in more detail, either over the phone or in person, if you need any further clarification or additional information.

Onsite Ground floor system

Most Passivhaus systems require a Passivhaus foundation system, which can be very expensive. With the Beattie Passive ground floor detail, we’re able to continue the insulation from the wall into the floor void – completing our continuously insulated structure. As a result, cost effective foundations can be used – usually strip foundations designed by us, but supplied by your local groundworker. As part of our design, we also ensure every project is flood and radon protected, as well as ventilated, to safeguard the structure for the lifetime of the building.

Cavity insulation

Our patented approach enables the insulation to flow around the whole structure. This means there are no gaps or joints.

High performance cavity insulation is applied onsite by skilled installers to guarantee the delivery of a continuous insulated building that is tested by thermal imaging. Due to our unique patent, we’re the only company who can deliver continuous insulation around a building. The injected EPS bead insulation is made up of small round balls stuck together with a water based additive – beads: 98% steam and 2% recycled oil. We use bead as it doesn’t slump when wet, has high thermal properties and is A rated in the BRE Green Guide.


Beattie Passive’s design methodology details each junction for airtightness and achieves levels of 0.6ACH@50pa.

The system has continuous insulation within the walls, floor and roof, delivering Passivhaus standards of performance and significantly outperforming SIPs and other build systems. All structures are independently air tested and thermally imaged to give our clients complete peace of mind that we have delivered the designed performance.

Convection looping

Convection looping occurs when warm air from the inside hits the cold air on the outside of a building. It rises and convects, pulling more warm air to the outside. There are three main causes: cold bridges between timber studs and at junctions on walls, floors and roofs; gaps between insulation at abutments, and poorly fitted insulation in cavities.

The negative effect of convection looping can lead to

  • Reduced U-value performance
  • Increased heating requirements
  • Increased CO2 emissions
  • Distorted SAP calculations

Beattie Passive’s build system overcomes any issue with convection looping due to its continuous insulation seal. No gaps, no looping, no loss. Just a 3mm gap in your insulation or joints will alter U-values by 159%!

Thermal bypass

Known as thermal bypass, air movement across, within, and behind insulation increases heat loss, causes discomfort and enables mould growth. The Beattie Passive build system has been designed to completely eliminate the risk of thermal bypass because we create a continuous insulated envelope.

Although Passivhaus is primarily known as an energy efficiency standard, it is also a rigorous quality and performance standard. Our build system narrows the performance gap between what is designed and what is actually constructed.

Our build system has a noise dampening effect due to the insulation and windows


The Beattie Passive system has been developed to achieve the best possible acoustic performance, at least three times better than Building Regulation Standards. The system is proving highly popular for sites located close to schools, busy roads, train lines and flight paths.

Acoustics are particularly important for terraced houses and apartment buildings. The independent party wall and ceiling designs give high levels of sound proofing – up to 65db.

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