If you demolish anything is the castle that is fully built or in the process of building (time is counting down) you will receive half the resources cost. If you demolish a building that has been placed but has not started building you will receive the full resource cost back
The size of the castle area is 52 x 52 tiles
Before you start building any large amounts of castle structures you should max out your construction research.
To give an idea of how much it benefits you, it reduces the build time for great towers down from 24 hours to 9 hours 36 minutes.
Speeding up castles
The following cards can be used to finish your castle buildings extremely fast.
Using expert masons will increase your castle building time by 5 times, meaning you can get 30 hours of work done in just 6 hours.
However you can also use the master castle designer card when the expert mason’s card is running to boost its 6 hour build reduction time to an actual 30 hour reduction. If you use the master castle designer card normally it just knocks off 6 hours of your build time, but if you use it when expert masons is running then it knocks 6 hours of the reduced build time meaning it actually knocks the time down by 30 hours.