Fencalc XA2021
Envelope floors
Floors may form part of the thermal envelope where they separate conditioned space from outside air, ground or unconditioned zones.
How to use the diagram
Read the visual first, then connect each label to the lesson text and your calculator inputs. The aim is to make every assumption visible before you calculate.
Learning Objective
Separate internal floors from envelope floors.
Boundary clarity
The compliance boundary should match the building envelope used elsewhere in the assessment.
Practice Task
- Mark envelope floors on a section.
- List floor construction types.
Calculator Tip
Use consistent storey and envelope definitions across all modules.
Worked Example: Envelope Floor Decision
Scenario
A slab-on-ground living area and an internal upper floor both appear on the drawings.
Calculator Entry
Only enter floor assemblies that form part of the thermal envelope.
Step-by-step method
- 1Identify which floor separates conditioned space from ground, outside air or unconditioned space.
- 2Exclude internal floors that are not part of the thermal envelope.
- 3Record slab, insulation and edge assumptions.
- 4Check drawings against the floor compliance note.
Expected conclusion
Scope clarity prevents internal floors from distorting the envelope check.
Common Mistakes
- Including internal floors that are not part of the thermal envelope.
- Forgetting edge conditions, ground contact or unconditioned spaces.
- Merging different floor assemblies without a clear reason.
Quick Knowledge Check
1. What should you confirm before applying this lesson to a project?
Envelope boundary is clear.
2. Which piece of evidence should support the main input in this lesson?
Mark envelope floors on a section.
3. What is the safest action if the information is incomplete?
Flag the missing evidence, use a conservative assumption where appropriate, and avoid claiming compliance until the information is confirmed.