diff --git a/solar/solar/core/validation.py b/solar/solar/core/validation.py
index e4efe4a0..8e12bf57 100644
--- a/solar/solar/core/validation.py
+++ b/solar/solar/core/validation.py
@@ -69,15 +69,19 @@ def _construct_jsonschema(schema, definition_base=''):
     :return:
     """
     if schema == 'str':
-        return {'type': 'string'}, {}
+        return {'anyOf': [{'type': 'string'}, {'type': 'null'}]}, {}
 
     if schema == 'str!':
         return {'type': 'string', 'minLength': 1}, {}
 
-    if schema == 'int' or schema == 'int!':
+    if schema == 'int':
+        return {'anyOf': [{'type': 'number'}, {'type': 'null'}]}, {}
+    if schema == 'int!':
         return {'type': 'number'}, {}
 
-    if schema == 'bool' or schema == 'bool!':
+    if schema == 'bool':
+        return {'anyOf': [{'type': 'boolean'}, {'type': 'null'}]}, {}
+    if schema == 'bool!':
         return {'type': 'boolean'}, {}
 
     if isinstance(schema, list):
diff --git a/solar/solar/test/test_validation.py b/solar/solar/test/test_validation.py
index 0e5339bb..65b3c129 100644
--- a/solar/solar/test/test_validation.py
+++ b/solar/solar/test/test_validation.py
@@ -38,6 +38,12 @@ input:
         errors = sv.validate_resource(r)
         self.assertListEqual(errors.keys(), ['value-required'])
 
+        r = self.create_resource(
+            'r4', sample_meta_dir, {'value': None, 'value-required': 'y'}
+        )
+        errors = sv.validate_resource(r)
+        self.assertEqual(errors, {})
+
     def test_input_int_type(self):
         sample_meta_dir = self.make_resource_meta("""
 id: sample
@@ -70,6 +76,12 @@ input:
         errors = sv.validate_resource(r)
         self.assertListEqual(errors.keys(), ['value-required'])
 
+        r = self.create_resource(
+            'r4', sample_meta_dir, {'value': None, 'value-required': 2}
+        )
+        errors = sv.validate_resource(r)
+        self.assertEqual(errors, {})
+
     def test_input_dict_type(self):
         sample_meta_dir = self.make_resource_meta("""
 id: sample