Assemblies: Walls, Roofs, Transitions, Windows & Doors
Now we apply everything so far to real assemblies. The point is not “one perfect wall,” but learning how to evaluate assemblies by control-layer continuity, buildability, and risk concentration at transitions.
Potential agenda
- Intro (2 min): “Assemblies succeed at transitions.”
- Desired outcome (6–8 min): What makes an assembly robust (not fragile)
- Common failures (6–8 min): Where assemblies usually fail: windows, roofs, decks, penetrations
- Core concepts (6–8 min): Buildability, sequencing, and responsibilities between trades
- Takeaways (2–3 min): A short “assembly evaluation checklist”
- Discussion (30–45 min): Prompts embedded below
Desired outcome
- Clear control-layer mapping through the entire assembly and every transition.
- Buildable details that don’t require “hero installers.”
- Risk managed at transitions (water, air, thermal, and structural handoffs).
- Maintainability: assemblies that can be inspected, repaired, and upgraded.
Discussion prompt
- Most fragile detail: What detail in your local practice feels most “fragile” to you—and why?
Common failures
Assembly failure patterns When control layers don’t line up across transitions
- Window/door integration failures: drainage, flashing, and air sealing not coordinated.
- Roof-to-wall failures: water shedding and air barrier continuity broken at eaves and rakes.
- Penetration failures: pipes, vents, and fasteners interrupt layers without a reliable patch strategy.
- Deck/ledger and balcony failures: concentrated wetting + structural connections + thermal bridging.
Examples (worked into failures)
Example — “Good wall, bad window opening”
Field of wall is airtight and well-insulated, but the opening is leaky or traps water; the failure is localized and expensive.
Example — Transition stack-up changes in the field
A minor change (different window flange, different trim detail, different WRB tape) breaks the shingle-lap logic or air continuity.
Discussion prompt
- Trade coordination: Where do you see handoffs between trades fail most often?
Core concepts
Buildability is performance
If a detail can’t be repeated reliably, it’s not a “high-performance” detail—it’s a risk generator.
Sequencing matters
Many failures happen because the “right thing” is installed at the wrong time, or the next trade undoes it.
Define responsibility explicitly
Someone must “own” the air barrier continuity. Someone must “own” the drainage plane continuity.
Transitions deserve disproportionate attention
Openings and connections are where loads and flows concentrate—so that’s where details should be strongest.
Takeaways
- Evaluate assemblies by continuity, risk concentration, and buildability.
- Good drawings aren’t enough; you need sequencing and handoff clarity.
- Most “mystery failures” start at a transition: openings, penetrations, roof-to-wall, slab-to-wall.
- Next (P11): we integrate the enclosure with mechanical systems and operation.
Further reading
Optional links will be added here (short, high-credibility readings that match the session focus).