PassivPod is an innovative, comfortable and sustainable building with several applications, such as a holiday home, primary home or educational classroom. This page details some of the key environmental benefits and design features.
The design is founded on well established ‘Passivhaus’ principles starting with its compact organic form that offers the least surface area for the volume enclosed. The glazing orientation is predominantly south and recessed allowing low-level winter sun to penetrate while excluding the intense summer sun.
Bathrooms are located on the north side with minimal glazing and both east and west windows are shaded by external louvres keeping the building comfortable throughout the summer. A roof-lit central stairwell acts as the ‘heart and lungs’ of the PassivPod, bringing daylight down to the entrance area and assisting with summer cooling by providing ventilation and drawing cool night time air through the building.
The ground floor living or teaching space is open-plan, loosely divided by furniture to promote sociability and inclusion. The space will enjoy great south facing views and will have direct outside access via a deck area allowing the interior space to merge with the outdoor space.
“When Mark showed me the conceptual images of the PassivPod, ideas of how to engineer and build it quickly came to mind. We can quickly test and refine these ideas due to our engineering experience and close working relationship with timber fabricators. We are confident that by adopting our design processes, we can provide an efficient engineered structural solution for the PassivPods.
“We are really excited about developing this design and look forward to working with Koru Architects.”
– Bola Ogunmefun (MEng CEng MIStructE), Lyons O’Neill
Construction & Materials
PassivPod components will largely be pre-fabricated off-site in factory conditions where quality can be ensured and wastage minimised. The curved cross-laminated timber frame (CLT) from base to gutter-line will be a uniform profile replicated around the perimeter and will be stabilised by external sheathing and the timber roof deck and stair core. The foundation will be a reinforced GGBS concrete raft to minimise both ground disturbance and cement use. The external skin will be Western Red Cedar shingles which, as it weathers, will both blend in with and enhance the natural setting.
The roof finish will be a flexible polyolefin membrane and the windows will be timber/aluminium composite framed and triple glazed. To promote a healthy internal environment, non-toxic, natural products such as sheep’s wool or hemp insulation will be used and vapour permeability will be ensured providing breathable walls.
Airtightness will ensure a draft/condensation-free internal environment which, along with natural paints and finishes, will enhance the health and wellbeing of the occupants.
A major advantage of CLT is its inherent fire resistance. Unlike steel, CLT remains structurally stable under high temperatures. There has been significant fire testing in Europe, Canada and more recently, in the USA. Fire testing shows CLT will char in a predictable manner and we can calculate fire resistance based on the number and thickness of plys that each panel is made from (taking into account the CLT adhesive used). This charring actually provides the fire resistance – the timber burns at a steady rate, creating a black layer of char which becomes an insulating layer, preventing an excessive rise in temperature within the core of the panel. The unaffected core continues to function for the period of the fire resistance.
The measure of fire resistance is the time elapsed from the start of the fire up until the point where the material fails to function, usually expressed in minutes, e.g. FR 30, 45, 60, 120.
Sustainability & Renewable Technologies
PassivPod will be the epitome of a low energy, low water consumption building, achieving strict Passivhaus standards for energy efficiency. A high efficiency mechanical ventilation system with heat recovery will ventilate the house providing high indoor air quality to all rooms.
The PassivPod ‘hybrid’ solar roof will generate 4.2kWp from its flexible solar PV array and a network of pipework directly beneath the roof finish will cool the PV panels and supply heat to a 500 litre thermal store, contributing substantially to the occupants’ hot water demand.
A room-sealed wood burning stove in the down-stairs open-plan area will provide supplementary heat in the winter months if needed. A 4,700 litre rainwater harvesting tank will supply the WC cisterns and garden hose (plus the washing machine for leisure and living applications) and, along with low-flow tap fittings, will hugely reduce water consumption. To assist with summer cooling the stairwell roof-light will have automatic actuation triggered by heat sensors.
If you have any questions about PassivPod’s design or technology, please contact one of our team for further information.