Taking a fabric first approach to retrofitting training

The Waterford and Wexford Education and Training Board (WWETB) retrofit training course in the NZEB Training Centre is based on the National Standards Authority of Ireland’s SR:54. The national standard aims to bring our retrofit projects to a BER rating of B2, which is 125kWhm² per annum.

The training also focuses on international standards PAS 2035 which introduces the trainees to the new role of the retrofit coordinator. Successful retrofits begin with a robust survey and assessment of the building. Having assessed the project, we explain the requirement to plan and design solutions, since each home is different with respect to construction and user type.

The training takes a “fabric first” approach, so we look at different strategies to make the thermal envelope (roof, walls, floor, windows, and doors) more energy efficient. There are a variety of wall rigs on display in our training centre, demonstrating examples of the different approaches that can be taken to improve U-values, depending on the construction.

Retrofitting the junctions between the elements is crucial, so the theory is translated into practical exercises that instil best practice and demonstrate how to mitigate thermal bridging.

Next, we analyse the airtightness levels of our dwellings and, more importantly, the vapour movement within and vapour balance between the humidity producing activities within the dwelling. We demonstrate how improvements to airtightness and humidity levels are achieved. We simulate a blower-door test in the purpose-built airtight house. There are practical exercises, where specialised membranes and tapes are applied to a custom-built airtight rig. Spray on liquid membrane is demonstrated, and the combination of insulation and membrane applications reinforce the theories learned.

A new addition to the training is virtual reality exercise, where the learner virtually insulates a variety of wall and roof types. Airtight exercises are included, and the sequencing required for the strategy is examined. The learner experiences the process of installing a ventilation system, in a virtual building site. These exercises have proven to be hugely beneficial, demonstrating the sequencing that these tasks require.

The correct ventilation strategy for a retrofit, is hugely important, and approaches taken are dependent on the building type and scope of the retrofit. We examine solutions, such as MVHR, which are very intrusive, and other options, such as decentralised systems which are less invasive. We look at ventilation strategies specific to retrofit scenarios, and demo these in the airtight house.

We analyse case studies that demonstrate the problems and solutions to different scenarios that are encountered. Case studies that are exemplar in retrofit going beyond the B2 standard to the EnerPHit standard; they focus on various issues that will occur in our retrofits, fabric, airtightness, doors and windows, ventilation, and renewable energy technologies.

You may be eligible for Government Skills to Advance funding to attend an NZEB Training course (Irish PPS number required). Please contact for more details.

E: nzeb@wwetb.ie
W: www.wwetbtraining.ie/nzeb