diff --git a/Riot/ViewController/RoomViewController.m b/Riot/ViewController/RoomViewController.m
index 004881301..4afd9fb21 100644
--- a/Riot/ViewController/RoomViewController.m
+++ b/Riot/ViewController/RoomViewController.m
@@ -1605,7 +1605,33 @@
         {
             previewHeader.mainHeaderContainer.hidden = NO;
             previewHeader.mainHeaderBackgroundHeightConstraint.constant = previewHeader.mainHeaderContainer.frame.size.height;
-            
+
+            if ([previewHeader isKindOfClass:PreviewRoomTitleView.class])
+            {
+                // In case of preview, update the header height so that we can
+                // display as much as possible the room topic in this header.
+                // Note: the header height is the previewHeader.mainHeaderBackgroundHeightConstraint
+                // just computed
+                PreviewRoomTitleView *previewRoomTitleView = (PreviewRoomTitleView *)previewHeader;
+
+                // Compute the height required to display all the room topic
+                CGSize sizeThatFitsTextView = [previewRoomTitleView.roomTopic sizeThatFits:CGSizeMake(previewRoomTitleView.roomTopic.frame.size.width, MAXFLOAT)];
+
+                // Increase the preview header height according to the room topic height
+                // but limit it in order to let room for room messages at the screen bottom.
+                // This free space depends on the device.
+                // On an iphone 5 screen, the room topic height cannot be more than 50px.
+                // Then, on larger screen, we can allow it a bit more height but we
+                // apply a factor to give more priority to the display of more messages.
+                CGFloat screenHeight = [[UIScreen mainScreen] bounds].size.height;
+                CGFloat maxRoomTopicHeight = 50 + (screenHeight - 568) / 3;
+
+                CGFloat additionalHeight = MIN(maxRoomTopicHeight, sizeThatFitsTextView.height)
+                                            - previewRoomTitleView.roomTopic.frame.size.height;
+
+                previewHeader.mainHeaderBackgroundHeightConstraint.constant += additionalHeight;
+            }
+
             [self setRoomTitleViewClass:RoomAvatarTitleView.class];
             // Note the avatar title view does not define tap gesture.