Astrid Madsen
Near Zero Energy Building (NZEB) regulations are constantly evolving to ensure that new and existing buildings become more energy efficient. With the recent updates, a common question that many homeowners in Ireland ask is whether these regulations apply to extensions and renovations.
Do NZEB Building Regulations Apply to Extensions and Renovations?
Understanding Major Renovations:
NZEB’s updated regulations introduce a requirement for “major renovations” to meet a “cost optimal” energy performance standard, which is equivalent to a minimum Building Energy Rating (BER) of B2. This is, however, subject to the feasibility in technical, functional, and economic terms.
Defining a Major Renovation:
The term “major renovation” refers to the renovation of an existing dwelling where over 25% of the surface area of the building’s thermal envelope is renovated.
Unpacking the “Thermal Envelope”
To understand the scope of the regulations better, one needs to comprehend the concept of the ‘thermal envelope’. Essentially, it’s the entire surface area of a building that can potentially lose heat to the external environment or the ground. This includes the heat loss areas of walls, windows, floors, and the roof.
For Instance:
If a homeowner decides to fit their property with external wall insulation (EWI) and simultaneously upgrades the windows and doors, these changes might cover 25% or more of the thermal envelope’s surface area.
Guidelines and References for Homeowners
TGD L is a technical guidance document that provides homeowners with valuable information on this topic. Two key sections are:
Appendix F of TGD L:
This appendix gives homeowners examples on how to determine the percentage of the renovated surface area for various types of dwellings.
Table 7 of TGD L:
Table 7 highlights the categories of significant renovation works that meet the cost-optimal performance level. It’s essential to understand that Table 7’s guidelines are for works “planned as a single project.” This implies that the 25% rule isn’t meant to accumulate over several projects or periods.
Extensions and the “Major Renovation” Requirement
If you’re considering extending your dwelling, the “Major Renovation” criterion might come into play, particularly if the renovation affects 25% or more of the existing thermal envelope’s heat-loss surface.
For Semi-Detached Dwellings:
Typically, this would entail extending both the rear wall and the gable wall to meet the requirement.
For Terraced Houses:
Interestingly, party walls in terraced houses aren’t regarded as heat loss walls. This means that merely extending the rear part of the house might suffice to cross the 25% threshold.
Consultation is Key
Before embarking on any renovation or extension project, it’s paramount to consult with an energy assessor, architect, or another qualified building professional. They will be able to provide tailored advice and clarify whether your proposed changes fall above or below the crucial 25% threshold.
Conclusion
With the environment taking center stage in most policy decisions, it’s essential for homeowners in Ireland to be aware of the NZEB building regulations, especially when considering renovations or extensions. By understanding the guidelines and seeking professional advice, homeowners can ensure that their renovations not only add value to their property but also contribute to a sustainable future.
