diff --git a/domain/modelling/optimisation/optimiser.py b/domain/modelling/optimisation/optimiser.py
index b47495f00..aa220dc07 100644
--- a/domain/modelling/optimisation/optimiser.py
+++ b/domain/modelling/optimisation/optimiser.py
@@ -248,7 +248,41 @@ def optimise_package_fabric_first(
         target_sap=target_sap,
         dependencies=dependencies,
     )
-    return fabric_package
+    if (
+        target_sap is not None
+        and fabric_package.score.sap_continuous >= target_sap
+    ):
+        return fabric_package
+
+    # Phase 2 — the upgrade requirement is not met by fabric alone: optimise
+    # the remaining groups (non-fabric, plus any fabric group phase 1 left
+    # unpicked) on top of the committed fabric. Every score call is prefixed
+    # with the phase-1 overlays, so candidates are valued against the
+    # fabric-applied dwelling and the resulting package score stays the
+    # truthful whole-package figure against the original baseline.
+    remaining_groups: list[list[ScoredOption]] = [
+        group
+        for index, group in enumerate(groups)
+        if index not in _used_group_indices(groups, fabric_package.selected)
+    ]
+    post_fabric_scorer = _PrefixedScorer(
+        scorer, [scored.option.overlay for scored in fabric_package.selected]
+    )
+    leftover_budget: Optional[float] = (
+        None if budget is None else budget - _package_cost(fabric_package.selected)
+    )
+    top_up: OptimisedPackage = optimise_package(
+        groups=remaining_groups,
+        scorer=post_fabric_scorer,
+        baseline_epc=baseline_epc,
+        budget=leftover_budget,
+        target_sap=target_sap,
+        dependencies=dependencies,
+    )
+    return OptimisedPackage(
+        selected=[*fabric_package.selected, *top_up.selected],
+        score=top_up.score,
+    )
 
 
 def _is_fabric_group(group: list[ScoredOption]) -> bool:
@@ -259,6 +293,23 @@ def _is_fabric_group(group: list[ScoredOption]) -> bool:
     )
 
 
+class _PrefixedScorer:
+    """A Scorer view of the dwelling with a committed package already applied:
+    every score call sees the ``prefix`` overlays before the candidate's own.
+    Phase 2 of Fabric First scores through this, so its candidates are valued
+    against the post-fabric dwelling while the returned Score remains the
+    truthful whole-package figure against the true baseline."""
+
+    def __init__(self, inner: Scorer, prefix: Sequence[EpcSimulation]) -> None:
+        self._inner = inner
+        self._prefix = list(prefix)
+
+    def score(
+        self, baseline: EpcPropertyData, simulations: Sequence[EpcSimulation]
+    ) -> Score:
+        return self._inner.score(baseline, [*self._prefix, *simulations])
+
+
 def _with_role1_signals(
     dependencies: Sequence[MeasureDependency],
     scorer: Scorer,