ExAC Podcast | Examitect

The closer a wall sits to a boundary, the more carefully its openings and construction need to be considered. We introduce exposing building face, limiting distance, and unprotected openings, then follow them into the Part 9 tables. The examples show why the wall area and the type of building matter before you read off a percentage.

A house needs fresh air in different seasons, and the heating system needs to support the spaces it serves. We look at ventilation, heat recovery, design temperatures, and the related provisions around chimneys and garages. The episode brings these requirements together as practical questions about comfort, air movement, and the equipment that needs to be accommodated.

The bottom edge of a wall is a tough place for cladding. We look at why wood, masonry, and metal need clearance from the ground, and how moisture and salt affect them differently. We also discuss attachment and support, then return to assembly tables as a way to understand what the completed exterior wall delivers.

A roof needs to shed water even when winter makes that difficult. We explore flashing, slopes, and the way ice dams form when melting snow reaches a cold overhang. The discussion then connects protective measures and attic ventilation to the same practical goal: keeping water from finding a path back into the building.

Moisture control and thermal performance meet inside the wall assembly. We look at the purpose of a vapour barrier, insulation requirements, and the tables used to describe standard assemblies. We also discuss support spacing and finishes, showing how ordinary movement in a building can affect the thickness and durability of the materials attached to it.

Small air leaks can carry a steady energy penalty. We explore why the air barrier became an important part of envelope design and what it is trying to stop. The discussion also introduces Part 9's approach to insulation and energy requirements, helping place air leakage within the wider performance of the wall and roof.

The foundation needs to manage more than the weight of the building. We look at protection against soil gas and the drainage measures used to keep water from collecting around walls and beneath slabs. The episode connects membranes, perimeter drainage, and site conditions, showing why the below-grade layers need to be considered as a working system.

A lintel carries the load over an opening back into the wall on either side. We use that simple picture to explain why a wider opening changes the member needed above it. We also look at lumber, built-up, and engineered options, and how to recognise when a code table can be used and when a calculation is needed.

Wall framing choices depend on what the studs need to support. We compare load-bearing and non-load-bearing walls, then look at blocking, strapping, and the differences between interior and exterior steel studs. The episode connects the standard arrangements to their limits, including when a design moves beyond the familiar options and needs engineering input.

A span table answers a useful question when you bring it the right information. We follow species, grade, size, spacing, and span through a floor-joist example, then look at the notes for bridging and strapping. The discussion also explains why floor, ceiling, and roof members need different tables and different assumptions about the loads.