diff --git a/source/common/router/header_parser_utils.cc b/source/common/router/header_parser_utils.cc
index 345e9045498e..f92986d1cdc7 100644
--- a/source/common/router/header_parser_utils.cc
+++ b/source/common/router/header_parser_utils.cc
@@ -39,7 +39,7 @@ std::string HeaderParser::translateMetadataFormat(const std::string& header_valu
       }
       new_format = parsed_params->asObjectArray()[0]->asString();
       for (size_t i = 1; i < parsed_params->asObjectArray().size(); i++) {
-        new_format += ":" + parsed_params->asObjectArray()[i]->asString();
+        absl::StrAppend(&new_format, ":", parsed_params->asObjectArray()[i]->asString());
       }
 
       new_format = absl::StrCat("%", matches[1], "_METADATA(", new_format, ")%");
diff --git a/source/common/runtime/runtime_impl.cc b/source/common/runtime/runtime_impl.cc
index 81bc35baaf29..2a4deeee8b2e 100644
--- a/source/common/runtime/runtime_impl.cc
+++ b/source/common/runtime/runtime_impl.cc
@@ -720,7 +720,7 @@ SnapshotImplPtr LoaderImpl::createNewSnapshot() {
       std::string path =
           layer.disk_layer().symlink_root() + "/" + layer.disk_layer().subdirectory();
       if (layer.disk_layer().append_service_cluster()) {
-        path += "/" + service_cluster_;
+        absl::StrAppend(&path, "/", service_cluster_);
       }
       if (api_.fileSystem().directoryExists(path)) {
         TRY_ASSERT_MAIN_THREAD {
diff --git a/source/extensions/filters/udp/dns_filter/dns_filter_utils.cc b/source/extensions/filters/udp/dns_filter/dns_filter_utils.cc
index 5b8670b9360d..c37f6d77563d 100644
--- a/source/extensions/filters/udp/dns_filter/dns_filter_utils.cc
+++ b/source/extensions/filters/udp/dns_filter/dns_filter_utils.cc
@@ -52,11 +52,11 @@ std::string buildServiceName(const std::string& name, const std::string& proto,
   if (name[0] != '_') {
     result += "_";
   }
-  result += name + ".";
+  absl::StrAppend(&result, name, ".");
   if (proto[0] != '_') {
     result += "_";
   }
-  result += proto + '.' + domain;
+  absl::StrAppend(&result, proto, ".", domain);
   return result;
 }