As it happens, there's a page devoted to house rules in the 4e DMG. From p 189:the canonical tools, even the rule books, don't allow or at least facilitate house rules and DM creations
As Dungeon Master, you wear several hats: storyteller, rules arbiter, actor, adventure designer, and writer. Some DMs like to add a sixth hat to that stack: rules designer. House rules are variants on the basic rules designed specifically for a particular DM’s campaign. They add fun to your D&D game by making it unique, reflecting specific traits of your world.
A house rule also serves as a handy “patch” for a game feature that your group dislikes. The D&D rules cannot possibly account for the variety of campaigns and play styles of every group. If you disagree with how the rules handle something, changing them is within your rights.
A house rule also serves as a handy “patch” for a game feature that your group dislikes. The D&D rules cannot possibly account for the variety of campaigns and play styles of every group. If you disagree with how the rules handle something, changing them is within your rights.
It then goes on to give advice on designing and implementing house rules, with two worked examples.