--- a/runtime/src/lib.rs
+++ b/runtime/src/lib.rs
@@ -450,7 +450,7 @@
 	pub const DepositPerContract: Balance = TombstoneDeposit::get();
 	pub const DepositPerStorageByte: Balance = deposit(0, 1);
 	pub const DepositPerStorageItem: Balance = deposit(1, 0);
-	pub RentFraction: Perbill = Perbill::from_rational_approximation(1u32, 30 * DAYS);
+	pub RentFraction: Perbill = Perbill::from_rational(1u32, 30 * DAYS);
 	pub const SurchargeReward: Balance = 150 * MILLIUNIQUE;
 	pub const SignedClaimHandicap: u32 = 2;
 	pub const MaxDepth: u32 = 32;