diff --git a/apps/api/src/api/tool_instances.py b/apps/api/src/api/tool_instances.py
index 2bff619..30bad13 100644
--- a/apps/api/src/api/tool_instances.py
+++ b/apps/api/src/api/tool_instances.py
@@ -588,7 +588,8 @@ async def create_instance(
             image_tag = f"headquarter/{instance_name}:latest".lower()
             
             if tool_type.dockerfile_template:
-                returncode, stdout, stderr = build_image(
+                returncode, stdout, stderr = await asyncio.to_thread(
+                    build_image,
                     instance_dir=instance_dir,
                     dockerfile=tool_type.dockerfile_template,
                     tag=image_tag,