diff --git a/contracts/TimeManagerV5.sol b/contracts/TimeManagerV5.sol
index 59ba7c3..52167d1 100644
--- a/contracts/TimeManagerV5.sol
+++ b/contracts/TimeManagerV5.sol
@@ -11,25 +11,39 @@ contract TimeManagerV5 {
     /// @dev Sets true when block timestamp is used
     bool public isTimeBased;
 
+    /// @dev Sets true when contract is initialized
+    bool private isInitialized;
+
+    /**
+     * @dev Retrieves the current slot
+     * @return Current slot
+     */
+    function() view returns (uint256) private _getCurrentSlot;
+
     /**
      * @dev This empty reserved space is put in place to allow future versions to add new
      * variables without shifting down storage in the inheritance chain
      * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
      */
-    uint256[47] private __gap;
+    uint256[48] private __gap;
 
     /**
-     * @dev Retrieves the current slot
-     * @return Current slot
+     * @dev Function to simply retrieve block number or block timestamp
+     * @return Current block number or block timestamp
      */
-    function() view returns (uint256) private _getCurrentSlot;
+    function getBlockNumberOrTimestamp() public view returns (uint256) {
+        return _getCurrentSlot();
+    }
 
     /**
+     * @dev Initializes the contract to use either blocks or seconds
      * @param timeBased_ A boolean indicating whether the contract is based on time or block
      * If timeBased is true than blocksPerYear_ param is ignored as blocksOrSecondsPerYear is set to SECONDS_PER_YEAR
      * @param blocksPerYear_ The number of blocks per year
      */
-    constructor(bool timeBased_, uint256 blocksPerYear_) public {
+    function _initializeTimeManager(bool timeBased_, uint256 blocksPerYear_) internal {
+        if (isInitialized) revert("Already initialized TimeManager");
+
         if (!timeBased_ && blocksPerYear_ == 0) {
             revert("Invalid blocks per year");
         }
@@ -40,14 +54,7 @@ contract TimeManagerV5 {
         isTimeBased = timeBased_;
         blocksOrSecondsPerYear = timeBased_ ? SECONDS_PER_YEAR : blocksPerYear_;
         _getCurrentSlot = timeBased_ ? _getBlockTimestamp : _getBlockNumber;
-    }
-
-    /**
-     * @dev Function to simply retrieve block number or block timestamp
-     * @return Current block number or block timestamp
-     */
-    function getBlockNumberOrTimestamp() public view returns (uint256) {
-        return _getCurrentSlot();
+        isInitialized = true;
     }
 
     /**
diff --git a/contracts/test/ScenarioTimeManagerV5.sol b/contracts/test/ScenarioTimeManagerV5.sol
new file mode 100644
index 0000000..26ef5c6
--- /dev/null
+++ b/contracts/test/ScenarioTimeManagerV5.sol
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: BSD-3-Clause
+pragma solidity 0.5.16;
+
+import { TimeManagerV5 } from "../TimeManagerV5.sol";
+
+contract ScenarioTimeManagerV5 is TimeManagerV5 {
+    function initializeTimeManager(bool timeBased_, uint256 blocksPerYear_) external {
+        _initializeTimeManager(timeBased_, blocksPerYear_);
+    }
+}
diff --git a/tests/hardhat/TimeManagerV5.ts b/tests/hardhat/TimeManagerV5.ts
index f27c852..caf9413 100644
--- a/tests/hardhat/TimeManagerV5.ts
+++ b/tests/hardhat/TimeManagerV5.ts
@@ -8,8 +8,9 @@ describe("TimeManagerV5: tests", async () => {
   describe("For block number", async () => {
     const blocksPerYear = 10512000;
     beforeEach(async () => {
-      const timeManagerV5 = await ethers.getContractFactory("TimeManagerV5");
-      timeManager = await timeManagerV5.deploy(false, blocksPerYear);
+      const timeManagerV5 = await ethers.getContractFactory("ScenarioTimeManagerV5");
+      timeManager = await timeManagerV5.deploy();
+      await timeManager.initializeTimeManager(false, blocksPerYear);
     });
 
     it("Retrieves block timestamp", async () => {
@@ -20,8 +21,9 @@ describe("TimeManagerV5: tests", async () => {
   });
   describe("For block timestamp", async () => {
     beforeEach(async () => {
-      const timeManagerV5 = await ethers.getContractFactory("TimeManagerV5");
-      timeManager = await timeManagerV5.deploy(true, 0);
+      const timeManagerV5 = await ethers.getContractFactory("ScenarioTimeManagerV5");
+      timeManager = await timeManagerV5.deploy();
+      await timeManager.initializeTimeManager(true, 0);
     });
 
     it("Retrieves block timestamp", async () => {