Before creating a magnificent castle or city, an architecturally inclined wizard should hone his skills on smaller projects. One excellent project idea is to build homes for your followers. This can help improve follower loyalty with very little actual cost.
The Foundation
In most areas, a sturdy house cannot be built directly on the ground. Instead, you must dig a foundation upon which to build the structure. The foundation should be dug below the frost line and onto either bedrock or firmer soil.
The lowest-level spell for digging foundations is Expeditious Excavation. Expeditious Excavation can move one five foot cube of “earth, dust, and sand” — but not rock. If you are digging through rock, you will need a spell like Disintegrate. Disintegrate destroys “as much as a 10-foot cube of nonliving matter”. Disintegrate is a 6th level spell. Let’s assume that we will dig the foundation 5′ deep and build it up 1′ above the ground.
After you create a hole for a foundation, you should fill it in with stone using Wall of Stone. Wall of Stone is a 5th level spell. A wall of stone is 1″ thick per 4 caster levels and composed of up to one 5-foot square per level. At 12th level, this means you can use Wall of Stone to create a block of stone three inches thick covering twelve 5-foot squares. Or, you could create a block of stone three feet thick covering one 5-foot square. This means that you can use two castings of Wall of Stone to create one six-foot tall block of stone filling a 5×5 area of the foundation. If you cast Wall of Stone three times a day, you can create the 64 blocks necessary in 43 days. Of course, if you have the Echoing Spell feat, bonus spells due to high intelligence, or more spells due to being higher level, this can go even faster.
Wall of Stone does not appear to limit you as to what type of stone you can create. I recommend diorite. In addition to excellent durability, diorite does not exhibit the radon issues related to granite.
The Walls
Walls can be created in the same manner as the foundation. External walls should be at least one foot thick. Stone walls have one major issue, which is that stone is excellent at conducting heat and cold and is a terrible insulator. For insulation purposes, you can create an outer stone wall and an inner stone wall which are separated by an air gap. Trapped air is a surprisingly effective insulator. Stone wool is an even better insulator and can be created by combining Wall of Stone with Fabricate.
The Roof
The reason our structure is only 20′ wide is that a span over 20 feet created with Wall of Stone must be arched and buttressed, which makes design and construction more complex. The easiest roof is a mostly flat roof that is slightly thicker in the front than the back. This will force rainwater to drain off the back of the house.
Doors and Windows
Doors, windows, and other moving parts are too complicated to create with Fabricate. This is an area where you will need to hire skilled craftsmen.
Furnishings
You can create a wall of stone in almost any shape you desire. This means that Wall of Stone can be used to create fireplaces, chimneys, shelves, counters, and tables. You can even create bathtubs and sinks.