Hello. I've spent some time reading the forum and I have found lots of helpful information, so thank you. I am about to lay some click engineered flooring over my 2 reception rooms and hallway. In the reception rooms there is 22mm caberdek on a suspended floor but the hallway is an old terrazzo floor and the adjoining cloak room/cupboard under the stairs in the hallways is old quarry tiles. House was built 1927 so hallway and cloakroom are original. My plan is to use Stopgap 1200 over the hallway/cloakroom to bring the area to the exact same level as the other rooms, then 3mm underlay with integral dpm over the lot so I can float a floor right through. Would you recommend any extra liquid dpm like F77 over the terrazzo and quarry tiles either before or after the stopgap 1200?