diff --git a/src/components/views/messages/RoomCreate.js b/src/components/views/messages/RoomCreate.js
index f9dc3df2dc..95254323fa 100644
--- a/src/components/views/messages/RoomCreate.js
+++ b/src/components/views/messages/RoomCreate.js
@@ -49,7 +49,7 @@ module.exports = React.createClass({
             return <div />; // We should never have been instaniated in this case
         }
         const prevRoom = MatrixClientPeg.get().getRoom(predecessor['room_id']);
-        const permalinkCreator = new RoomPermalinkCreator(prevRoom);
+        const permalinkCreator = new RoomPermalinkCreator(prevRoom, predecessor['room_id']);
         permalinkCreator.load();
         const predecessorPermalink = permalinkCreator.forEvent(predecessor['event_id']);
         return <div className="mx_CreateEvent">
diff --git a/src/matrix-to.js b/src/matrix-to.js
index a198bb422e..14467cb4c5 100644
--- a/src/matrix-to.js
+++ b/src/matrix-to.js
@@ -70,8 +70,12 @@ const MAX_SERVER_CANDIDATES = 3;
 // the list and magically have the link work.
 
 export class RoomPermalinkCreator {
-    constructor(room) {
+    // We support being given a roomId as a fallback in the event the `room` object
+    // doesn't exist or is not healthy for us to rely on. For example, loading a
+    // permalink to a room which the MatrixClient doesn't know about.
+    constructor(room, roomId=null) {
         this._room = room;
+        this._roomId = room ? room.roomId : roomId;
         this._highestPlUserId = null;
         this._populationMap = null;
         this._bannedHostsRegexps = null;
@@ -79,6 +83,10 @@ export class RoomPermalinkCreator {
         this._serverCandidates = null;
         this._started = false;
 
+        if (!this._roomId) {
+            throw new Error("Failed to resolve a roomId for the permalink creator to use");
+        }
+
         this.onMembership = this.onMembership.bind(this);
         this.onRoomState = this.onRoomState.bind(this);
     }
@@ -116,13 +124,13 @@ export class RoomPermalinkCreator {
     }
 
     forEvent(eventId) {
-        const roomId = this._room.roomId;
+        const roomId = this._roomId;
         const permalinkBase = `${baseUrl}/#/${roomId}/${eventId}`;
         return `${permalinkBase}${encodeServerCandidates(this._serverCandidates)}`;
     }
 
     forRoom() {
-        const roomId = this._room.roomId;
+        const roomId = this._roomId;
         const permalinkBase = `${baseUrl}/#/${roomId}`;
         return `${permalinkBase}${encodeServerCandidates(this._serverCandidates)}`;
     }
@@ -246,7 +254,6 @@ export class RoomPermalinkCreator {
     }
 }
 
-
 export function makeUserPermalink(userId) {
     return `${baseUrl}/#/${userId}`;
 }