Handling Unrenovated Space in LEED Major Renovation Projects

Green Building Team on August 16, 2023

Rating System/Standard
LEED v4.1
Certification essentials
Green Building

Many project teams are managing major renovations of existing buildings and applying for certification under LEED BD+C. While most major renovation projects impact 100% of the interior space, sometimes there might be a small portion of existing area which will not be renovated, such as having an existing tenant remaining in place through the renovations. It can be difficult to administer these projects where not 100% of the interior space will be impacted by the renovation. A frequent question CAGBC review staff receive is if the unrenovated portions of the building, especially existing tenant areas, can be treated similar to “incomplete space” (e.g., future tenant areas).

The short answer to that is no; these unrenovated areas are not considered “incomplete spaces.” “Incomplete space” is space that will require fit up after applying for certification; in most cases, after certification, that fit up will be following tenant guidelines, Tenant Sales and Lease Agreements (TSLAs), or in the case of owner-occupied space, will be fit up according to an owner commitment letter. (See also the definitions on incomplete/complete space.) Unrenovated space is different from “incomplete space” as it exists in a completed state prior to the scope of the LEED project – which, in this case, is a major renovation. These spaces need to be included in the LEED project boundary and credit calculations, with their “existing condition”.

However, the LEED v4 BD+C Reference Guide does provide some special allowances for handling of existing space within other credits. Some key examples are outlined below:

WEp Indoor Water Use Reduction:

Existing plumbing fixtures are not required to be WaterSense labeled to meet the requirements of the prerequisite, but they still must be included in the Indoor Water Use Reduction calculations with their flush and flow rates. For appliances and process equipment, the existing equipment is not required to comply with Tables 2 and 3 under this prerequisite.

EAp Minimum Energy Performance:

There is special direction for handling existing systems and equipment that are not being modified within the project scope; some of these are not required to comply with the mandatory requirements of ASHRAE 90.1-2010 for EAp Minimum Energy Performance, but still must be included in the energy performance documentation for Option 1 Whole Building Energy Simulation and modeled based on the existing conditions.

EQp Minimum Indoor Air Quality Performance:

The entire building must meet the prerequisite ventilation requirements, including both renovated and the unrenovated ventilation systems that will be retained. Additionally, all existing and new ventilation systems must meet the applicable monitoring requirement unless the exemption for small systems noted in LEED Interpretation 10461 applies. However, the reference guide provides special direction for Core and Shell (CS) projects, noting “If the scope of the core-and-shell project does not include mechanical systems, the project is exempt from the ventilation and monitoring requirements.” All mechanical systems that are under the control of the base building owner/manager are required to meet the prerequisite requirements, including existing systems. If the ventilation systems serving the existing spaces (tenant or common areas) are under the building owner/manager’s control, then they could not be excluded from the prerequisite.

EQc Low Emitting Materials:

Existing materials and furniture are not required to be evaluated in this credit, as long as these materials have been in place for at least one year.

For some credits impacted by interior fit up, such as credits within Materials and Resources, many are based on new materials being added to the project and thus not impacted by the existing spaces. For credits within Indoor Environmental Quality, most would be impacted by the existing spaces and must be included. These include credits such as EQc Daylight, EQc Quality Views, EQc Thermal Comfort, EQc Interior Lighting, and EQc Acoustic Performance, where the existing spaces (that were not renovated) would be evaluated based on the existing conditions. Note that the LEED v4/v4.1 BD+C:CS rating system does not include the credits EQc Thermal Comfort, EQc Interior Lighting, and EQc Acoustic Performance.

Can the “10% Incomplete Exemption” apply to unrenovated spaces? No, the special allowance for LEED BD+C (non CS) noted in LEED Interpretation 10102 and the LEED v4.1 BD+C Beta Guide, to exempt 10% of the project total gross floor area (or 1860 square meters, whichever is less) from the binding owner commitment and tenant guidelines requirements, does not apply to unrenovated spaces, since these spaces are already completed.

If you have specific questions relating to this issue for your LEED project, please reach out. For information on handling incomplete space, please see CAGBC’s Treatment of Incomplete Space in BD+C resource.

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