diff --git a/configs/flix.nix b/configs/flix.nix
index d87d653..9cdc468 100644
--- a/configs/flix.nix
+++ b/configs/flix.nix
@@ -5,6 +5,7 @@ let
   indexFilename = "index";
   flixUser = "flix";
   flixGroup = "users";
+  inherit (import <niveum/lib>) tmpfilesConfig;
 in {
   fileSystems.${flixLocation} = {
     device = "prism.r:/export";
@@ -24,7 +25,13 @@ in {
   };
 
   systemd.tmpfiles.rules = [
-    "d '${cacheLocation}' 0750 ${flixUser} ${flixGroup} - -"
+    (tmpfilesConfig {
+      type = "d";
+      path = cacheLocation;
+      mode = "0750";
+      user = flixUser;
+      group = flixGroup;
+    })
   ];
 
   systemd.services.flix-index = {
diff --git a/configs/radio.nix b/configs/radio.nix
index e9a4947..21e10b9 100644
--- a/configs/radio.nix
+++ b/configs/radio.nix
@@ -1,6 +1,6 @@
 { lib, pkgs, config, ... }:
 let
-  inherit (import <niveum/lib>) nixpkgs-unstable;
+  inherit (import <niveum/lib>) nixpkgs-unstable tmpfilesConfig;
   radioStore = "/var/lib/radio";
   htgenPort = 8080;
   meddl = { streamPort = 8000; mpdPort = 6600; };
@@ -40,7 +40,13 @@ in
   ];
 
   systemd.tmpfiles.rules = [
-    "d '${radioStore}' 0755 ${config.users.extraUsers.radio.name} - 1d -"
+    (tmpfilesConfig {
+      type = "d";
+      path = radioStore;
+      mode = "0755";
+      user = config.users.extraUsers.radio.name;
+      age = "1d";
+    })
   ];
 
   users.extraUsers.radio.isSystemUser = true;
diff --git a/lib/default.nix b/lib/default.nix
index bc03860..7ca321b 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -5,6 +5,8 @@ rec {
   };
   nixpkgs-unstable = import nixpkgs-src { config.allowUnfree = true; };
 
+  tmpfilesConfig = {type, path, mode ? "-", user ? "-", group ? "-", age ? "-", argument ? "-"}: "${type} '${path}' ${mode} ${user} ${group} ${age} ${argument}";
+
   sshPort = 22022;
 
   colours = import ./colours/mac-os.nix;