diff --git a/internal/web/posts.go b/internal/web/posts.go
index b448853..35d2f2e 100644
--- a/internal/web/posts.go
+++ b/internal/web/posts.go
@@ -93,7 +93,8 @@ func (s *Server) handleCreatePost(w http.ResponseWriter, r *http.Request) {
 	)
 }
 
-// notifyPostReply asynchronously emails the direct parent post's author.
+// notifyPostReply emails the root homeowner for admin replies and the direct
+// parent author for homeowner replies.
 func (s *Server) notifyPostReply(
 	parent *store.Post,
 	root *store.Post,
@@ -104,13 +105,19 @@ func (s *Server) notifyPostReply(
 		root == nil ||
 		reply == nil ||
 		replyAuthor == nil ||
-		s.cfg.Mail == nil ||
-		parent.AuthorID == replyAuthor.ID {
+		s.cfg.Mail == nil {
 		return
 	}
 	if _, disabled := s.cfg.Mail.(mail.Nop); disabled {
 		return
 	}
+	recipientID := parent.AuthorID
+	if replyAuthor.Admin() {
+		recipientID = root.AuthorID
+	}
+	if recipientID == replyAuthor.ID {
+		return
+	}
 	msg := mail.PostReply{
 		RootID:          root.ID,
 		RootTitle:       root.Title,
@@ -118,7 +125,6 @@ func (s *Server) notifyPostReply(
 		ReplyBody:       reply.Body,
 		ReplyAuthorName: replyAuthor.Name,
 	}
-	recipientID := parent.AuthorID
 	go func() {
 		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 		defer cancel()
diff --git a/internal/web/posts_test.go b/internal/web/posts_test.go
index 0ea4829..8e798a1 100644
--- a/internal/web/posts_test.go
+++ b/internal/web/posts_test.go
@@ -334,6 +334,22 @@ func TestPostReplyNotifications(t *testing.T) {
 		t.Fatalf("homeowner reply notification = %+v", msg)
 	}
 
+	rec = postForm(handler, "/posts", url.Values{
+		"_csrf":     {adminCSRF},
+		"parent_id": {adminReply.ID},
+		"body":      {"One more plumber detail."},
+	}, adminCookies)
+	if rec.Code != http.StatusSeeOther {
+		t.Fatalf("nested admin reply status = %d: %s", rec.Code, rec.Body.String())
+	}
+	msgs = waitForMail(t, recording, 3)
+	if msg := msgs[2]; msg.ToEmail != homeowner.Email ||
+		msg.RootID != root.ID ||
+		msg.ReplyBody != "One more plumber detail." ||
+		msg.ReplyAuthorName != admin.Name {
+		t.Fatalf("nested admin reply notification = %+v", msg)
+	}
+
 	rec = postForm(handler, "/posts", url.Values{
 		"_csrf":     {homeownerCSRF},
 		"parent_id": {root.ID},
@@ -376,7 +392,7 @@ func TestPostReplyNotifications(t *testing.T) {
 		t.Fatalf("no-email reply status = %d: %s", rec.Code, rec.Body.String())
 	}
 	time.Sleep(50 * time.Millisecond)
-	if recording.Len() != 2 {
+	if recording.Len() != 3 {
 		t.Fatalf("self, edit, or no-email action sent a notification: %+v", recording.Snapshot())
 	}
 }