diff --git a/deployment/terraform/lambda/modelling_e2e/main.tf b/deployment/terraform/lambda/modelling_e2e/main.tf
index 4be3bd2a8..9995f7fe4 100644
--- a/deployment/terraform/lambda/modelling_e2e/main.tf
+++ b/deployment/terraform/lambda/modelling_e2e/main.tf
@@ -24,6 +24,20 @@ locals {
   # truth. At N=32 → 4.0s. Consumed by the handler's throttle (see
   # infrastructure/solar/google_solar_api_client.py).
   solar_min_request_interval_seconds = var.maximum_concurrency / (0.8 * 600 / 60)
+
+  # Root of the expired-EPC backup — the old register's final dump, sharded one
+  # `{POSTCODE}/data.csv.gz` per postcode under `historical_epc/` in the data bucket.
+  # Turns on Expired-Enhanced Prediction (ADR-0054): a prediction conditioned by the
+  # dwelling's expired pre-2012 certificate is persisted as source="expired" rather
+  # than "predicted", so reporting can tell "no EPC at all" apart from "only an
+  # expired one".
+  #
+  # `retrofit_sap_data_bucket_name` is — despite the name — the `retrofit-data-<stage>`
+  # bucket (shared/main.tf); engine and fast-api already take it from this output rather
+  # than rebuilding the string, so the bucket name has one source of truth. Reads need no
+  # IAM change: modelling_e2e_s3_read already grants GetObject + ListBucket across that
+  # whole bucket, which covers historical_epc/.
+  historic_epc_s3_root = "s3://${data.terraform_remote_state.shared.outputs.retrofit_sap_data_bucket_name}/historical_epc"
 }
 
 module "lambda" {
@@ -55,6 +69,10 @@ module "lambda" {
     DATA_BUCKET          = "retrofit-data-${var.stage}"
 
     SOLAR_MIN_REQUEST_INTERVAL_SECONDS = tostring(local.solar_min_request_interval_seconds)
+
+    # Expired-Enhanced Prediction (ADR-0054). Empty ⇒ the handler never builds the
+    # reader and every prediction stays plain "predicted".
+    HISTORIC_EPC_S3_ROOT = local.historic_epc_s3_root
   }
 }