My house subsided about a year ago due to a leaking underground drain it has now been underpinned but just on one corner which they said should be fine (i hope it will be). The problem is the floor which is concrete has dropped by about a inch and i need to build it back up...... any idea whats best to use but it must be self levelling and set quickly as i have two dogs and its right by the back door.......... Would be grateful for any advice xxxxxxxxxxxxxxx