Total building excludes capitol: 45
In your city there is 2 type of ruined tiles
Small tiles: exclusively for mansion/ farmhouse
Big tiles: for others
Recommendations of city buildings layout(for beginners which actually you can use it till you have reach level 30 capitol)
12 mansion
12 farmhouse
1 lumberjack house
1 stonecutter house
1 foundry
10 barracks
1 Academy
1 consulate
1 tar workshop
1 forge
1 portal master
1 caravan
1 warehouse
1 temple