I'm having a problem putting a second floor onto a stronghold sized building (8x4 - 32 tiles). It is stone walled, pre-existing 1.0 (at least 6 month) and all walls are completed. It had stone slab paving on all florrs. My carpentry is 71.49, my masonry 70.56, my paving 24.20. I have more than 10 other buildings of various sizes (shack, cottage, villa, mansion, estate), all pre-existing, with which I have no problem making multi-storey. If I start a new stronghold size building (6x6 - 36 tiles) i have no problem planning floor below and floor above even before a single nail or brick is added. For the problem building when I plan a floor below the option to plan anything additional on the tile, except interior walls when rt clicking on the borders, dissapears. I've tried completly building the floor on the tile, planning additional internal walls, removing the slab paving, planning all floor tiles, all to not effect. Any help out there?