diff --git a/fs.go b/fs.go
index 77dce66..b5733cf 100644
--- a/fs.go
+++ b/fs.go
@@ -51,18 +51,24 @@ func (fs *FS) ServeHTTP(w http.ResponseWriter, r *http.Request, info RoutingInfo
 	}
 
 	// search for file in static file system
-	file, err := fs.findFile(url)
+	file, filePath, err := fs.findFile(url)
 	if err != nil {
 		http.NotFound(w, r)
 		return
 	}
+	// check, if the file is a folder
+	file, ok := fs.checkFolder(file, filePath)
+	if !ok {
+		http.NotFound(w, r)
+		return
+	}
 	defer file.Close()
 
 	// serve file content
 	fs.serve(w, r, info, file)
 }
 
-func (fs *FS) findFile(url string) (fs.File, error) {
+func (fs *FS) findFile(url string) (fs.File, string, error) {
 	// build file path
 	filePath := path.Join(fs.FolderPrefix, url)
 	filePath = strings.TrimPrefix(filePath, "/")
@@ -71,15 +77,40 @@ func (fs *FS) findFile(url string) (fs.File, error) {
 	if fs.UseLocalFolder {
 		localFilePath := path.Join(fs.LocalFolderPrefix, filePath)
 		localFilePath = strings.TrimPrefix(localFilePath, "/")
+		if localFilePath == "" {
+			localFilePath = "."
+		}
 
 		file, err := os.Open(localFilePath)
 		if err == nil {
-			return file, nil
+			return file, localFilePath, nil
 		}
 	}
 
 	// use static file system
-	return fs.StaticFiles.Open(filePath)
+	if filePath == "" {
+		filePath = "."
+	}
+	file, err := fs.StaticFiles.Open(filePath)
+	return file, filePath, err
+}
+
+func (fs *FS) checkFolder(file fs.File, url string) (fs.File, bool) {
+	fileInfo, err := file.Stat()
+	if err != nil {
+		_ = file.Close()
+		return file, false
+	}
+
+	// check for folder / root location
+	if fileInfo.IsDir() {
+		// close folder handler (we don't need it anymore)
+		_ = file.Close()
+
+		return file, false
+	}
+
+	return file, true
 }
 
 func (fs *FS) serve(w http.ResponseWriter, r *http.Request, info RoutingInfo, file fs.File) {
diff --git a/fs_test.go b/fs_test.go
index 5b74c64..049acc8 100644
--- a/fs_test.go
+++ b/fs_test.go
@@ -114,6 +114,48 @@ func TestFSLicense(t *testing.T) {
 	}
 }
 
+func TestFSFolder(t *testing.T) {
+	// create new FS
+	fs := NewFS(&staticFiles)
+
+	// serve the request
+	tw := &testWriter{}
+	tr := &http.Request{
+		Method: http.MethodHead,
+		URL: &url.URL{
+			Path: "/",
+		},
+	}
+	fs.ServeHTTP(tw, tr, RoutingInfo{})
+
+	// check data
+	if tw.statusCode != http.StatusNotFound {
+		t.Error("received invalid http status code", tw.statusCode)
+	}
+}
+
+func TestFSFolderLocal(t *testing.T) {
+	// create new FS
+	fs := NewFS(&staticFiles)
+	fs.UseLocalFolder = true
+	fs.LocalFolderPrefix = "/"
+
+	// serve the request
+	tw := &testWriter{}
+	tr := &http.Request{
+		Method: http.MethodHead,
+		URL: &url.URL{
+			Path: "/",
+		},
+	}
+	fs.ServeHTTP(tw, tr, RoutingInfo{})
+
+	// check data
+	if tw.statusCode != http.StatusNotFound {
+		t.Error("received invalid http status code", tw.statusCode)
+	}
+}
+
 func TestFSNotFound(t *testing.T) {
 	// create new FS
 	fs := NewFS(&staticFiles)