diff --git a/packages/types/src/codec/create/registry.ts b/packages/types/src/codec/create/registry.ts
index 793cdedf41..e5d4dc1fbc 100644
--- a/packages/types/src/codec/create/registry.ts
+++ b/packages/types/src/codec/create/registry.ts
@@ -10,7 +10,7 @@ import { assert, isFunction, isString, isUndefined, stringCamelCase, u8aToHex }
 
 import Raw from '../Raw';
 import { EventData } from '../../primitive/Generic/Event';
-import { defaultExtensions, expandExtensionTypes, findUnknownExtensions } from '../../primitive/Extrinsic/SignedExtensions';
+import { defaultExtensions, expandExtensionTypes, findUnknownExtensions } from '../../primitive/Extrinsic/signedExtensions';
 import { createClass } from './createClass';
 import { getTypeClass } from './getTypeClass';
 import { getTypeDef } from './getTypeDef';
diff --git a/packages/types/src/primitive/Extrinsic/SignedExtensions.ts b/packages/types/src/primitive/Extrinsic/signedExtensions/index.ts
similarity index 61%
rename from packages/types/src/primitive/Extrinsic/SignedExtensions.ts
rename to packages/types/src/primitive/Extrinsic/signedExtensions/index.ts
index 836ef756f4..6ad6b76dba 100644
--- a/packages/types/src/primitive/Extrinsic/SignedExtensions.ts
+++ b/packages/types/src/primitive/Extrinsic/signedExtensions/index.ts
@@ -2,62 +2,21 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
-import { InterfaceTypes } from '../../types';
+import { ExtDef, ExtInfo, ExtTypes } from './types';
 
-type ExtTypes = Record<string, InterfaceTypes>;
-type ExtInfo = {
-  extra: ExtTypes;
-  types: ExtTypes;
-}
+import polkadotExtensions from './polkadot';
+import substrateExtensions from './substrate';
 
 // A mapping of the known signed extensions to the extra fields that they contain. Unlike in the actual extensions,
 // we define the extra fields not as a Tuple, but rather as a struct so they can be named. These will be expanded
 // into the various fields when added to the payload (we only support V4 onwards with these, V3 and earlier are
 // deemded fixed and non-changeable)
-const allExtensions: Record<string, ExtInfo> = {
-  ChargeTransactionPayment: {
-    extra: {},
-    types: {
-      tip: 'Compact<Balance>'
-    }
-  },
-  CheckBlockGasLimit: {
-    extra: {},
-    types: {}
-  },
-  CheckEra: {
-    extra: {
-      blockHash: 'Hash'
-    },
-    types: {
-      era: 'ExtrinsicEra'
-    }
-  },
-  CheckGenesis: {
-    extra: {
-      genesisHash: 'Hash'
-    },
-    types: {}
-  },
-  CheckNonce: {
-    extra: {},
-    types: {
-      nonce: 'Compact<Index>'
-    }
-  },
-  CheckVersion: {
-    extra: {
-      specVersion: 'u32'
-    },
-    types: {}
-  },
-  CheckWeight: {
-    extra: {},
-    types: {}
-  }
+const allExtensions: ExtDef = {
+  ...substrateExtensions,
+  ...polkadotExtensions
 };
 
-// the v4 signed extensions (the order is important here)
+// the v4 signed extensions (the order is important here, as applied by default)
 const defaultExtensions: Array<keyof typeof allExtensions> = [
   'CheckVersion',
   'CheckGenesis',
diff --git a/packages/types/src/primitive/Extrinsic/signedExtensions/polkadot.ts b/packages/types/src/primitive/Extrinsic/signedExtensions/polkadot.ts
new file mode 100644
index 0000000000..6e8b64f61e
--- /dev/null
+++ b/packages/types/src/primitive/Extrinsic/signedExtensions/polkadot.ts
@@ -0,0 +1,16 @@
+// Copyright 2017-2020 @polkadot/types authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+import { ExtDef } from './types';
+
+export default {
+  RestrictFunctionality: {
+    extra: {},
+    types: {}
+  },
+  LimitParathreadCommits: {
+    extra: {},
+    types: {}
+  }
+} as ExtDef;
diff --git a/packages/types/src/primitive/Extrinsic/signedExtensions/substrate.ts b/packages/types/src/primitive/Extrinsic/signedExtensions/substrate.ts
new file mode 100644
index 0000000000..78dd430b33
--- /dev/null
+++ b/packages/types/src/primitive/Extrinsic/signedExtensions/substrate.ts
@@ -0,0 +1,48 @@
+// Copyright 2017-2020 @polkadot/types authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+import { ExtDef } from './types';
+
+export default {
+  ChargeTransactionPayment: {
+    extra: {},
+    types: {
+      tip: 'Compact<Balance>'
+    }
+  },
+  CheckBlockGasLimit: {
+    extra: {},
+    types: {}
+  },
+  CheckEra: {
+    extra: {
+      blockHash: 'Hash'
+    },
+    types: {
+      era: 'ExtrinsicEra'
+    }
+  },
+  CheckGenesis: {
+    extra: {
+      genesisHash: 'Hash'
+    },
+    types: {}
+  },
+  CheckNonce: {
+    extra: {},
+    types: {
+      nonce: 'Compact<Index>'
+    }
+  },
+  CheckVersion: {
+    extra: {
+      specVersion: 'u32'
+    },
+    types: {}
+  },
+  CheckWeight: {
+    extra: {},
+    types: {}
+  }
+} as ExtDef;
diff --git a/packages/types/src/primitive/Extrinsic/signedExtensions/types.ts b/packages/types/src/primitive/Extrinsic/signedExtensions/types.ts
new file mode 100644
index 0000000000..960f425602
--- /dev/null
+++ b/packages/types/src/primitive/Extrinsic/signedExtensions/types.ts
@@ -0,0 +1,14 @@
+// Copyright 2017-2020 @polkadot/types authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+import { InterfaceTypes } from '../../../types';
+
+export type ExtTypes = Record<string, InterfaceTypes>;
+
+export type ExtInfo = {
+  extra: ExtTypes;
+  types: ExtTypes;
+}
+
+export type ExtDef = Record<string, ExtInfo>;