A material substitution or relocated penetration can change an entire junction. Review changes before execution, while the decision can still be checked.
Typical trigger
A contractor proposes different insulation, a window, fixing or route because a product is unavailable. Price or thickness alone cannot establish technical equivalence.
Dependent functions
Check heat transfer, moisture, airtightness, loads and compatibility with adjacent layers. A duct-route change may affect resistance, noise and service access together.
Change request
Record the reason, original solution, proposed product and documentation. Identify drawings and calculations requiring revision and the person responsible for approval.
Review output
Retain a written decision, conditions, revised documents and execution checks. A concealed deviation may require a separate investigation rather than merely a log entry.
Common mistakes and boundaries
Verbal approval not shared with every trade leaves conflicting design versions. Support does not automatically include unlimited redesign; additional calculations and visits require agreement.
| Item | Parameter | Check / result |
|---|---|---|
| Proposal | Product and reason | Request |
| Assessment | All dependencies | Decision |
| Execution | Current revision | Record and inspection |
What this means for your project
Use a simple change register with responsibilities and drawing revisions. Review substitutions before procurement and concealment.
Sources and scope of review
Related reading
- Airtightness: What It Is and Why It Matters
- Ventilation Noise: Where It Comes From and How to Avoid It
- How to coordinate architectural, structural and services design packages