diff --git a/buildbot_nix/__init__.py b/buildbot_nix/__init__.py
index 20cbc94..3004f91 100644
--- a/buildbot_nix/__init__.py
+++ b/buildbot_nix/__init__.py
@@ -603,6 +603,7 @@ def config_for_project(
                     == c.properties.getProperty("github.repository.default_branch"),
                 ),
                 builderNames=[f"{project.name}/nix-eval"],
+                treeStableTimer=5,
             ),
             # this is compatible with bors or github's merge queue
             schedulers.SingleBranchScheduler(
diff --git a/nix/master.nix b/nix/master.nix
index 59b0d30..c168386 100644
--- a/nix/master.nix
+++ b/nix/master.nix
@@ -209,6 +209,6 @@ in
 
     # Allow buildbot-master to write to this directory
     systemd.tmpfiles.rules = lib.optional (cfg.outputsPath != null)
-      "d ${cfg.outputPath} 0755 buildbot buildbot - -";
+      "d ${cfg.outputsPath} 0755 buildbot buildbot - -";
   };
 }