Model/domain/modelling/generators/roof_recommendation.py
Khalim Conn-Kowlessar 1d13dee38e ND loft roof on a pre-1950 dwelling gets loft insulation 🟩
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-02 11:05:47 +00:00

176 lines
7.6 KiB
Python

"""The roof Recommendation Generator.
Dispatches the MAIN roof to its single applicable insulation Measure by roof
type (ADR-0021): a sloping ceiling (rafters, 100 mm), or — the fallback — a
loft / thatched / unlodged pitched roof (joists, 300 mm); a no-access roof gets
nothing. Each emits one "Roof" Recommendation whose Option carries the
insulation Simulation Overlay (raising `roof_insulation_thickness`) and a priced
Cost (roof area x the Product's fully-loaded unit cost, with its contingency).
Flat-roof and room-in-roof branches land in later slices. No scoring, no
persistence — impact is produced later by scoring (ADR-0016).
"""
from typing import Final, Optional, Union
from datatypes.epc.domain.epc_property_data import (
BuildingPartIdentifier,
EpcPropertyData,
)
from domain.building_geometry import roof_area
from domain.modelling.measure_type import MeasureType
from domain.modelling.recommendation import Cost, MeasureOption, Recommendation
from domain.modelling.simulation import BuildingPartOverlay, EpcSimulation
from repositories.product.product_repository import ProductRepository
_LOFT_MEASURE_TYPE = MeasureType.LOFT_INSULATION
_SLOPING_CEILING_MEASURE_TYPE = MeasureType.SLOPING_CEILING_INSULATION
# RdSAP 10 Table 16: 0 mm lodged roof insulation is an uninsulated loft. The
# Elmhurst mapper resolves "As Built" to 0 for pitched/sloping/loft roofs.
_ROOF_UNINSULATED_MM = 0
# Recommended loft-insulation depth (mm). Elmhurst re-lodges a loft-insulation
# measure at 300 mm; pinning the before→after cascade (000490/001431) requires
# the overlay to match that depth exactly (see test_elmhurst_cascade_pins).
_RECOMMENDED_LOFT_THICKNESS_MM = 300
# Recommended sloping-ceiling depth (mm); Elmhurst re-lodges 100 mm (ADR-0021).
_RECOMMENDED_SLOPING_CEILING_THICKNESS_MM = 100
# Age bands whose as-built pitched roof is uninsulated (ADR-0047: A-D
# uninsulated, E-F limited insulation, G+ insulated) — the resolution for a
# cert lodging the "ND" (Not Defined) sentinel or no thickness at all.
_AS_BUILT_UNINSULATED_AGE_BANDS: Final[frozenset[str]] = frozenset(
{"A", "B", "C", "D"}
)
def _pitched_roof_is_uninsulated(
thickness: Union[str, int, None], age_band: Optional[str]
) -> bool:
"""The pitched-roof uninsulated trigger, sentinel-aware (ADR-0047).
`roof_insulation_thickness` lodges numerics AND string sentinels; the
sentinels are data, not noise, and must never make an undefined cert MORE
eligible than an explicitly-lodged one. An explicit 0 is uninsulated; the
"ND" (Not Defined) sentinel — or nothing lodged — resolves to the age
band's as-built state (only A-D built without pitched-roof insulation).
Anything else ("NI" = insulation present at unknown thickness per RdSAP 10
§5.11.4, or a measured depth) means insulation is there. Eligibility only
— the calculator resolves the same sentinels separately for the U-cascade
(deliberate two-home split, ADR-0047)."""
if isinstance(thickness, int):
return thickness == 0
if thickness is None or thickness == "ND":
return (
age_band is not None
and age_band.upper() in _AS_BUILT_UNINSULATED_AGE_BANDS
)
return False
_FLAT_ROOF_MEASURE_TYPE = MeasureType.FLAT_ROOF_INSULATION
# Recommended flat-roof depth (mm); Elmhurst re-lodges 200 mm (ADR-0021).
_RECOMMENDED_FLAT_ROOF_THICKNESS_MM = 200
def recommend_roof_insulation(
epc: EpcPropertyData, products: ProductRepository
) -> Optional[Recommendation]:
"""Return the single roof-insulation Recommendation for the MAIN roof,
dispatched by roof type (ADR-0021): a sloping ceiling is insulated at the
rafters to 100 mm. Returns None when the roof type has no applicable measure
or the roof is already insulated."""
main = next(
part
for part in epc.sap_building_parts
if part.identifier is BuildingPartIdentifier.MAIN
)
# Room-in-roof safety guard (ADR-0021): a room-in-roof carries its
# insulation on its own sloping/stud/gable surfaces (RdSAP 10 §3.10, Table
# 17/18), which the loft/sloping overlay's flat `roof_insulation_thickness`
# bump cannot model. Without this guard a RR with an uninsulated loft would
# fall through to the loft fallback and mis-recommend loft insulation.
# Defer until a dedicated RR branch lands.
if main.sap_room_in_roof is not None:
return None
roof_type: str = (main.roof_construction_type or "").lower()
# Dispatch by roof type (ADR-0021). Order matters: a sloping ceiling is
# tested before the loft fallback, and "no access" before it too, because
# "no access to loft" contains "loft". Loft is the fallback — it covers a
# plain pitched loft, a thatched roof (the covering doesn't block insulating
# the loft floor), and an unlodged roof type (the modal UK case), matching
# the pre-dispatcher behaviour of firing on `roof_insulation_thickness == 0`.
# A vaulted ceiling follows the slope like a sloping ceiling (no loft
# void) — same disjunction the calculator's `is_sloping_ceiling` uses
# (heat_transmission.py), so generator and scorer read one story (ADR-0047).
if "sloping ceiling" in roof_type or "vaulted" in roof_type:
if not _pitched_roof_is_uninsulated(
main.roof_insulation_thickness, main.construction_age_band
):
return None
return _roof_recommendation(
epc,
products,
measure_type=_SLOPING_CEILING_MEASURE_TYPE,
description="Sloping-ceiling insulation (insulate at the rafters)",
thickness_mm=_RECOMMENDED_SLOPING_CEILING_THICKNESS_MM,
)
if "flat" in roof_type:
# A flat roof lodges no thickness when uninsulated ("As Built" → None
# on the Elmhurst path); a lodged thickness means it's already done.
if main.roof_insulation_thickness is not None:
return None
return _roof_recommendation(
epc,
products,
measure_type=_FLAT_ROOF_MEASURE_TYPE,
description="Flat-roof insulation",
thickness_mm=_RECOMMENDED_FLAT_ROOF_THICKNESS_MM,
)
if "no access" in roof_type:
return None # the roof void can't be reached to insulate it
if not _pitched_roof_is_uninsulated(
main.roof_insulation_thickness, main.construction_age_band
):
return None
return _roof_recommendation(
epc,
products,
measure_type=_LOFT_MEASURE_TYPE,
description="Loft insulation (top up to recommended depth)",
thickness_mm=_RECOMMENDED_LOFT_THICKNESS_MM,
)
def _roof_recommendation(
epc: EpcPropertyData,
products: ProductRepository,
*,
measure_type: MeasureType,
description: str,
thickness_mm: int,
) -> Recommendation:
"""Build a single-Option "Roof" Recommendation: the measure's insulation
overlay (raising `roof_insulation_thickness` to the recommended depth)
priced at the roof area."""
product = products.get(measure_type)
area: float = roof_area(epc, BuildingPartIdentifier.MAIN)
cost = Cost(
total=area * product.unit_cost_per_m2,
contingency_rate=product.contingency_rate,
)
option = MeasureOption(
measure_type=measure_type,
description=description,
overlay=EpcSimulation(
building_parts={
BuildingPartIdentifier.MAIN: BuildingPartOverlay(
roof_insulation_thickness=thickness_mm
)
}
),
cost=cost,
material_id=product.id,
)
return Recommendation(surface="Roof", options=(option,))