Successfully integrating new buildings with tie-ins into existing structures presents unique challenges especially when it comes to ensuring the performance and continuity of the building envelope. This technical presentation explores the design and evaluation strategies required to create durable, technically sound connections between new and existing wall and roof systems.

Attendees will begin by analyzing and comparing the functional characteristics of key exterior wall design types, including mass, transitional, barrier, drainage, and rainscreen systems. The session will also explore the differences between conventional and protected membrane roofing assemblies in low-slope roofs applications, focusing on performance implications relevant to new-to-existing roof tie-ins.

To support successful design decisions, participants will learn how to assess, document, and verify the construction and condition of existing walls and roofing systems. Emphasis will be placed on identifying key control layers (air, water, vapor, and thermal) and understanding how they interact within existing assemblies.

The presentation will focus on applying building envelope design fundamentals to the development of successful tie-ins between new buildings and existing structures. Strategies will be provided to ensure continuity across all control layers, minimize the risk of air leakage, moisture-related and thermal issues, and accommodate differing construction types, material differences, and movement accommodations.

By the end of the session, participants will be equipped with practical knowledge to evaluate existing conditions and confidently design new wall and roof transitions to existing structures that preserve the integrity and performance of the complete building envelope.