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ADR-022: Residential construction sets: opt-in Example fill, attic roofs, adiabatic source floors, and detailed documents read but not assigned

Status: Accepted (the owner's decisions of 2026-10-15, D-140). The detection rules and the reading of detailed documents are the controller's, provisional until the owner has read them. Superseded in part by D-142 (2026-10-16), removed in code by D-143: the attic roof, the garage-wall caveat, and the warning on adiabatic source floors (decisions 2 and 3, and the detection rules), because a single-dwelling set is now refused, and E2 (decision 4), which was dropped. Still in force: opt-in Fill From Example (decision 1), and the reading of detailed documents, now as evidence that is never converted.

Date: 2026-10-15

Decisions: D-137, D-138, D-140; refines ADR-021.

Design note: 2026-10-15-construction-json.md, build log "C2" and "E1" · Architecture: construction-json.md, convert2idf.md

Context

The atlas's packet v2 adds two residential pairs to the one-storey house of v1. All three sources are single detached dwellings (whole_dwelling), and no residential source has interior walls, interior floors, and exposed floors together. Reading their detailed conditions showed three things:

  • The attic. In the one-storey house, ExteriorRoof is the deck over a vented attic, and the insulation is in InteriorCeiling, between the conditioned space and the attic. ADR-021's mapping wrote the bare deck over conditioned zones.
  • The garage. The residential InteriorWall is a wall to a garage.
  • Adiabatic floors. The residential InteriorFloor comes mostly from floors that are adiabatic in the source.

The atlas also asked:

  • that a role a building needs but the set lacks give an actionable diagnostic, or an explicitly reviewed override, never a silent fill;
  • that both document kinds parse;
  • that parsing stay separate from assignment.

Decision

The owner's decisions (2026-10-15, D-140)

(Decisions 2 and 3 are superseded by D-142, and E2 in decision 4 is dropped; decision 1 stands.)

  1. Fill is opt-in. A role the set lacks is the error ConstructionMissing by default. Convert2IDF's Fill From Example (IdfOptions.FillFromExample) makes it the Example's construction with a warning, the reviewed override of D-138. The ground stays the Example's with a remark (D-137).
  2. Attic roofs. The roof of conditioned zones takes the attic ceiling, recorded as an approximation that leaves out the attic air and the roof deck. No attic zone is modelled.
  3. Adiabatic source floors written conductive by floor heat transfer give a warning, not an error.
  4. Order. C2 and then E1 without a stop. E2, the assignment of detailed rules, comes later.

Realisation (controller, provisional)

(D-142, D-143: the detection rules, the attic roof, and the Approximation and AdiabaticInSource properties are removed; a whole_dwelling set is refused with ConstructionJsonScopeNotSupported. The reading of detailed documents remains, as evidence only.)

  • Detection. The unified document carries no space types, so the residential rules key on the whole_dwelling scope:
  • InteriorCeiling and ExteriorRoof both ready means an attic roof;
  • InteriorWall carries the garage caveat;
  • InteriorFloor is flagged adiabatic in the source.

An explicit flag from the atlas would replace these rules. - The attic roof. It is the ceiling's layers under its own name ({ceiling id} as roof), with the source roof's exterior surface properties on the outside layer, because that face is now outdoors. It is recorded as RoleConstruction.Approximation, which gives ConstructionApproximation wherever a building uses the role. - Detailed documents. They are read into DetailedConstructionDocument, which keeps every condition, disposition, reversal flag, and geometry instruction as data and the assemblies in BEMGen's types. The set made from one carries AssignmentUnavailable, so a conversion is the compatibility error ConstructionAssignmentUnavailable, which names the unified document to use. Nothing about the detailed rules is applied.

Options considered

  • An attic zone. Rejected for now. It is a geometry element across every generator and aggregator, it needs a sourced attic ventilation rate, and it is geometry BEMGen's flat-roofed residential generators never had.
  • The bare roof deck as the roof (ADR-021's mapping). Rejected: about twenty times too conductive over conditioned rooms.
  • A compatibility error for attic roofs. Rejected by the owner in favour of the approximation, which keeps the one-storey house usable.
  • Fill on by default (D-138). Superseded: a silent fill on every residential conversion hides a mismatch between source and geometry.
  • Assign detailed rules with BEMGen's own space mapping now. Deferred to E2. BEMGen has no garage space type and no source storeys, so any mapping now would be a guess.

Consequences

(D-142, D-143: the bullets on the one-storey house, the floor heat transfer warning, and E2 no longer apply; the other bullets stand, with the five packet documents now seven, of which three building-scope ones convert.)

  • Fill. A residential set on a multi-zone plan needs Fill From Example, or a zoning without interior walls (Single Zone per Floor). Either choice is recorded in the IDF header.
  • The one-storey house converts with its insulated ceiling as the roof. Summer attic heat is missed, and winter heat loss is slightly overstated.
  • Floor heat transfer with a residential set warns that its interior floor's resistance was never meant for conduction between storeys.
  • All ten packet documents parse. The five unified ones convert, through every zoning in the test matrix, and the five detailed ones are refused with an actionable error.
  • E2 needs a design note: how detailed conditions bind to BEMGen zones, whether BEMGen gains a garage or unconditioned space type, and whether source storeys map to generated storeys.