DeltaQ within the RIBA Plan of Work

We work on the design and delivery of Passivhaus buildings through every stage of development. Here are key considerations for successful delivery of Passivhaus standards at each of the RIBA Plan of Work Stages.


Strategic definition

From the outset, it is useful to include strategic Passivhaus objectives in the project definition. Advising clients on the implications of Passivhaus, we also assist with the development of policy and practice supporting low energy building implementation across their organisations.

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RIBA stage 0 - Passivhaus objectives


Preparation & briefing

At this stage, clients and their advisers should become aware of the costs and constraints associated with Passivhaus and ensure that these are reflected in the project brief. Our strategic advice enables clients to properly consider the impact of adopting the Passivhaus Standard on a project-by-project basis. We develop generic and bespoke Employers’ Requirements for use across a range of projects.

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RIBA stage 1 - Passivhaus preparation and briefing


Concept design

This is where our design input begins. The location, orientation and form of a building all have a significant impact on building energy outcomes and on the ease with which the Passivhaus Standard can be met. Considering project objectives and site constraints, we advise designers on how these early design decisions affect achieving the standard.  

Feasibility studies to consider whether and how the constraints of Passivhaus and EnerPHit design can be aligned with project objectives and resources are also undertaken at this stage.

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RIBA stage 2 - Passivhaus concept design


Spatial co-ordination

This includes window, shading and ventilation design for daylighting, views and summer comfort, together with key aspects of the internal layout such as stair cores, access corridors, stacking and services conduits. Construction method may also be a factor in spatial co-ordination or conversely spatial co-ordination may dictate construction method. For apartment blocks, definition of the thermal envelope and consideration of the air test strategy is advised. At this stage we develop the first pass PHPP model to determine U-values and wall thicknesses and inform design decisions and test options.

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RIBA stage 3 - Passivhaus spacial co-ordination


Technical design

Development of detailed designs and quantification of the energy impacts run in parallel through this stage. While we use our experience to advise on tried and tested methods, we are also open to new approaches.

Technical design typically includes the following:  

  • Structural and architectural co-ordination
  • Junction detailing
  • Airtightness and testing strategy
  • Thermal bridge modelling
  • Energy efficient and Passivhaus compliant building services design and specification
  • Detailed energy assessment of plug in equipment
  • PHPP modelling
  • Evidence gathering
  • Pre-construction certifier review

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RIBA stage 4 - Passivhaus technical design



At the beginning of construction we prepare the contractor for implementation through:

  • Design review and risk identification
  • Site delivery plan and sequencing
  • Toolbox talks

We then provide a supporting role throughout construction, enabling the Passivhaus Champion to demonstrate that construction is in line with the design. Our role includes:

  • In person and video inspections
  • Development of a detailed Evidence Register, indicating the exact information required from site
  • Certifier liaison
  • Commissioning support

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RIBA stage 5 - Passivhaus construction



We aim to achieve Passivhaus certification within six weeks of practical completion by managing the information flow throughout construction and keeping certifiers appraised of likely timing of their final certification review.  

Beyond certification we are involved in snagging, handover and setting up monitoring. 

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RIBA stage 6 - Passivhaus handover



Building performance evaluation is an integral part of our service. This is usually a relatively light touch process involving setting up data collection, informal occupant interviews and reporting on performance against Passivhaus criteria and PHPP model results.  

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RIBA stage 7 - Passivhaus operation