House addons are deeds for items which are used to place an object in your home. Some types are purely decoration (such as the Hanging Skeleton), while others serve a purpose (such as the Anvil and Forge). Once placed, a house addon can be turned back into a deed by either double-clicking the object or using an axe class weapon on it.
The only place to buy these add-ons are from other players or player vendors. NPC shopkeepers do not sell house add-on deeds.
Some house add-ons that you can obtain are: abattoirs, anvils, ballot boxes, small and large beds, dart boards, flour mills, small and large forges, looms, ovens, pentagrams, pickpocket dips, spinning wheels, training dummies, and water troughs.
To place a house add-on, double-click the deed. You will be given a targeting cursor and you must target the tile(s) where you wish to place the add-on. If the location is valid then the House add-on will apear on that location.
The Interior Decorator can be purchased from an NPC Architect and has the ability to turn certain objects to face south-to-east, or east-to-south. Not all objects may be turned, and the tool will not allow you to manipulate items weighing more than 100 stones. The tool has the ability to raise or lower certain objects.
Certain pieces of elf-style furniture introduced with the Mondain's Legacy expansion are considered addons rather than furniture per se.
The ability to modify or demolish a house is limited while certain addons are present in the house.