Skyrim Hearthfire House Building Tutorial: Adding Wings to your Home

After you finish building the Main Hall and Cellar of your house, you should see a lot of new options pop up in the Drafting Table. These are new wings you can add to expand your newly built home.

Note: Building three wings will grant you the Architect Achievement. Building three different houses, each with three wings, grants you the Master Architect achievement.

Adding a Wing
Select the wing you want to add from the Drafting Table. Afterwards, you will use the Carpenter's Workbench to construct the different sections of that wing

Limitations and Wing Combinations
There are three possible wing locations on your house: East Wing, North Wing, and West Wing

Rules
The Maximum number of wings you can add to your house is three.
You can add one of each wing
You cannot add more of one of the same wing (so for example you cannot have two North Wings)

It follows that you can build a lot of different combinations, but you will only be able to build 3 houses for each character meaning 3 different combinations.

East Wing (Select One)

Addition - East Wing - Armory
Adds an armory in the East Wing, where you can store weapons and armor.

Addition - East Wing - Kitchen
Adds a kitchen to the East Wing with a stove and cooking pot, where you can cook food, pastries, and make candy.

Addition - East Wing - Library
You use your East Wing as a Library, with a lot of bookshelves where you can store and collect books.

North Wing (Select One) 

Addition - North Wing - Alchemy Laboratory
Use if you want to put an alchemy lab in your North Wing. Alchemy lab can be used to create potions and poisons.

Addition - North Wing - Storage Room
Use to add a storage area in your north wing. Good if you have lots of stuff to store

Addition - North Wing - Trophy Room
Build a trophy room in your North Wing. Use to display trophies from your various travels and adventures.

West Wing (Select One)

Addition - West Wing - Bedrooms
Use to add bedrooms to your west wing.  If you have a family with two adopted children, you should use this.

Addition - West Wing - Enchanter's Tower
Add an Enchanter's Tower with an Archane Enchanter. If you do a lot of Enchanting, this is a good addition to your home.

Addition- West Wing - Greenhouse
Add a Greenhouse in the West Wing, where you will grow food and alchemy ingredients.


Best House Wings Combinations
This is the suggested combinations for your house wing, but feel free to create your own combinations:

House #1: Falkreath - Lakeview Manor
East Wing: Kitchen
North Wing: Storage
West Wing: Bedrooms

Make the Lakeview Manor the primary residence for your character. It needs a kitchen for your wife to prepare food for your family, bedrooms for you, your spouse, and your adopted kids, as well as storage room to store stuff in.

House #2:  Hjaalmarch - Windstad Manor
East Wing: Library
North Wing: Trophy Room
West Wing: Enchanter's Tower

The Windstad Manor serves as a cool manor where you can gather all the interesting books you have collected in the library, display trophies from your journey in the Trophy Room, and work on enchanting in the Enchanter's Tower

House #3: The Pale - Heljarchen Hall
East Wing: Armory
North Wing: Alchemy Laboratory
West Wing:  Greenhouse

The combination of Greenhouse and Alchemy Laboratory in the same house is useful. You can grow ingredients in the Greenhouse and craft potions and poisons in the Alchemy Lab using those ingredients.

Also see wiki for more details on the various schematics in the Drafting Table:
Skyrim Hearthfire: Drafting Table