diff --git a/weave/trace_server/clickhouse_trace_server_migrator.py b/weave/trace_server/clickhouse_trace_server_migrator.py
index 9b5074330c0..b174be7a6e8 100644
--- a/weave/trace_server/clickhouse_trace_server_migrator.py
+++ b/weave/trace_server/clickhouse_trace_server_migrator.py
@@ -2,6 +2,7 @@
 import logging
 import os
 from typing import Optional
+import re
 
 from clickhouse_connect.driver.client import Client as CHClient
 
@@ -40,7 +41,24 @@ def __init__(
         self._initialize_migration_db()
 
     def _format_replicated_sql(self, sql_query: str) -> str:
-        return sql_query
+        """Format SQL query to use replicated engines if replicated mode is enabled.
+
+        Converts MergeTree engine variants to their Replicated counterparts:
+        - MergeTree -> ReplicatedMergeTree
+        - SummingMergeTree -> ReplicatedSummingMergeTree
+        - etc.
+        """
+        if not self.replicated:
+            return sql_query
+
+        # Match "ENGINE = <optional words>MergeTree" followed by word boundary
+        pattern = r'ENGINE\s*=\s*(\w+)?MergeTree\b'
+
+        def replace_engine(match):
+            engine_prefix = match.group(1) or ""
+            return f'ENGINE = Replicated{engine_prefix}MergeTree'
+
+        return re.sub(pattern, replace_engine, sql_query, flags=re.IGNORECASE)
 
     def _create_db_sql(self, db_name: str) -> str:
         replicated_engine = ""