diff --git a/scripts/preorder/custom_notifications/send-preorder-custom-300-notification.php b/scripts/preorder/custom_notifications/send-preorder-custom-300-notification.php
index c2074a683..2e71a86b2 100644
--- a/scripts/preorder/custom_notifications/send-preorder-custom-300-notification.php
+++ b/scripts/preorder/custom_notifications/send-preorder-custom-300-notification.php
@@ -28,12 +28,15 @@ SELECT
 FROM Preorder p
 INNER JOIN Preordercampaign pc ON p.preordercampaign_id = pc.id
 INNER JOIN PreordercampaignStatusnotificationMailtemplate pcsmt ON pc.id = pcsmt.preordercampaign_id
+INNER JOIN `" . ADDRESSDB_DBNAME . "`.Hausnummer hn ON p.adb_wohneinheit_id = hn.id
 INNER JOIN Preorderstatus ps_current ON p.status_id = ps_current.id
 INNER JOIN first_status_300_plus fs ON p.id = fs.preorder_id
 LEFT JOIN PreorderStatusnotificationLog psnl ON p.id = psnl.preorder_id AND psnl.email_type = '300-custom'
 WHERE p.type = 'order'
     AND ps_current.code >= 300 
     AND ps_current.code < 500
+    AND hn.id IS NOT NULL 
+    AND hn.tool_building_type = 1 -- Only consider residential buildings
     AND pcsmt.notification_type = 'logical'
     AND JSON_EXTRACT(pcsmt.logical_config, '$.type') = '300-custom'
     AND psnl.id IS NULL  -- No existing '300-custom' notification