diff --git a/migrations/ChangeCertificateColumnTypes.js b/migrations/ChangeCertificateColumnTypes.js
new file mode 100644
index 00000000..95e62ebf
--- /dev/null
+++ b/migrations/ChangeCertificateColumnTypes.js
@@ -0,0 +1,74 @@
+module.exports = {
+  up: (queryInterface, Sequelize) => {
+    // logic for transforming into the new state
+    const p1 = queryInterface.changeColumn(
+      'Certificate',
+      'amount',
+      {
+        type     : Sequelize.DOUBLE,
+        allowNull: true,
+      }
+    );
+    const p2 = queryInterface.changeColumn(
+      'Certificate',
+      'effectiveAmount',
+      {
+        type     : Sequelize.DOUBLE,
+        allowNull: true,
+      }
+    );
+    const p3 = queryInterface.changeColumn(
+      'Certificate',
+      'height',
+      {
+        type     : Sequelize.INTEGER,
+        allowNull: true,
+      }
+    );
+    const p4 = queryInterface.changeColumn(
+      'Certificate',
+      'validAtHeight',
+      {
+        type     : Sequelize.INTEGER,
+        allowNull: true,
+      }
+    );
+    return Promise.all([p1, p2, p3, p4]);
+  },
+  down: (queryInterface, Sequelize) => {
+    // logic for reverting the changes
+    const p1 = queryInterface.changeColumn(
+      'Certificate',
+      'amount',
+      {
+        type     : Sequelize.STRING,
+        allowNull: true,
+      }
+    );
+    const p2 = queryInterface.changeColumn(
+      'Certificate',
+      'effectiveAmount',
+      {
+        type     : Sequelize.STRING,
+        allowNull: true,
+      }
+    );
+    const p3 = queryInterface.changeColumn(
+      'Certificate',
+      'height',
+      {
+        type     : Sequelize.STRING,
+        allowNull: true,
+      }
+    );
+    const p4 = queryInterface.changeColumn(
+      'Certificate',
+      'validAtHeight',
+      {
+        type     : Sequelize.STRING,
+        allowNull: true,
+      }
+    );
+    return Promise.all([p1, p2, p3, p4]);
+  },
+};
diff --git a/models/claim.js b/models/claim.js
index 7145e9e0..992a7158 100644
--- a/models/claim.js
+++ b/models/claim.js
@@ -25,7 +25,7 @@ function sortResult (result, longId) {
   return shortId;
 }
 
-module.exports = (sequelize, { STRING, BOOLEAN, INTEGER, TEXT, ARRAY, DECIMAL, DOUBLE, Op }) => {
+module.exports = (sequelize, { STRING, BOOLEAN, INTEGER, TEXT, DOUBLE }) => {
   const Claim = sequelize.define(
     'Claim',
     {
@@ -34,7 +34,7 @@ module.exports = (sequelize, { STRING, BOOLEAN, INTEGER, TEXT, ARRAY, DECIMAL, D
         default: null,
       },
       amount: {
-        type   : STRING,
+        type   : DOUBLE,
         default: null,
       },
       claimId: {
@@ -54,7 +54,7 @@ module.exports = (sequelize, { STRING, BOOLEAN, INTEGER, TEXT, ARRAY, DECIMAL, D
         default: null,
       },
       effectiveAmount: {
-        type   : STRING,
+        type   : DOUBLE,
         default: null,
       },
       hasSignature: {
@@ -62,7 +62,7 @@ module.exports = (sequelize, { STRING, BOOLEAN, INTEGER, TEXT, ARRAY, DECIMAL, D
         default: null,
       },
       height: {
-        type   : STRING,
+        type   : INTEGER,
         default: null,
       },
       hex: {
@@ -82,7 +82,7 @@ module.exports = (sequelize, { STRING, BOOLEAN, INTEGER, TEXT, ARRAY, DECIMAL, D
         default: null,
       },
       validAtHeight: {
-        type   : STRING,
+        type   : INTEGER,
         default: null,
       },
       outpoint: {