diff --git a/include/wrenpp/detail/string_bt.hpp b/include/wrenpp/detail/string_bt.hpp
index 2ea006e..112f1d5 100644
--- a/include/wrenpp/detail/string_bt.hpp
+++ b/include/wrenpp/detail/string_bt.hpp
@@ -146,7 +146,7 @@ namespace dhandy {
 		template <std::size_t S, typename Ch>
 		template <std::size_t Start, std::size_t Len>
 		constexpr auto string<S, Ch>::substr() const {
-			return string<std::min(S - 1 - std::min(Start, S - 1), Len) + 1, Ch>(m_data + std::min(Start, S - 1), 0) + string("");
+			return string<std::min(S - 1 - std::min(Start, S - 1), Len) + 1, Ch>(m_data + std::min(Start, S - 1), 0) + string<1, Ch>({Ch{}});
 		}
 	} //namespace bt
 } //namespace dhandy