diff --git a/soapbox/app.py b/soapbox/app.py
index 81ebfda..7d3805e 100644
--- a/soapbox/app.py
+++ b/soapbox/app.py
@@ -41,8 +41,9 @@ def create_app(cfg: Config | None = None) -> Flask:
 
     gitstore.ensure_repo(cfg.content_dir)
     _bootstrap_owner(cfg)
-    if not cfg.public_dir.exists():
-        build_site(cfg)
+    # Bygg alltid ved oppstart: etter en oppgradering kan maler/tema ha endret
+    # seg uten at innholdet har det, og da ville public/ vært utdatert.
+    build_site(cfg)
 
     @app.before_request
     def _open_db():
diff --git a/tests/test_app.py b/tests/test_app.py
index 3a09710..6b80d05 100644
--- a/tests/test_app.py
+++ b/tests/test_app.py
@@ -225,3 +225,11 @@ def test_user_theme_in_content_repo(client, cfg):
         f"/admin/edit/{pid}", data={"csrf": token, "title": "P", "body": "x", "action": "publish"}
     )
     assert '<article class="post">' in client.get("/p/").text
+
+
+def test_rebuild_on_startup(cfg):
+    """Utdatert public/ (f.eks. etter oppgradering) skal erstattes ved oppstart."""
+    cfg.public_dir.mkdir(parents=True)
+    (cfg.public_dir / "index.html").write_text("GAMMEL")
+    create_app(cfg)
+    assert "GAMMEL" not in (cfg.public_dir / "index.html").read_text()