Now you’ve got a spot- you know where you want to build your standing structure on the surface of the world. So what’s next? The foundation.
In the real world, foundations are a necessity- you need something solid for your building to be rooted on. If you don’t have such a thing laid out, your building will tend to collapse slowly under its own weight, and it will be more vulnerable to natural disasters- earthquakes will collapse it easily, floods will wash it away, windstorms will tear it up and scatter it across the landscape.
In Minecraft, foundations aren’t really necessary in that sense. Every block is just as sturdy as every other block in most if not all situations and there are no earthquakes or tornadoes to destroy your house by random chance. Even a structure floating in the air is perfectly stable (though difficult to get to). However, the concept and even the structure of a foundation can still be useful.
Once more, I’m going to break styles of building into two separate categories: The planning style, and the wing-it style.
Planners will love foundations. It can be hard to keep track in your head of exactly how long each side of your structure is or is going to be. You can alleviate this by digging out the ground on which your home is going to stand and replacing it with stone, wood, and other materials in a pattern that will remind you of where you intend to place what.
Those who wing it will not have this need. These players build what they need as they need it and don’t mind that things don’t fit perfectly together or that there’s an airspace in the middle of one of their walls. Their only concern is having enough space beforehand to build into- and when all else fails, might as well build up.
That isn’t to say that foundations aren’t useful to an ad-lib builder. Even when you’re just setting a core structure, a foundation can come in handy.
By essentially sinking stone columns into the dirt below, you are marking your building space underground- if you do this, then you can easily construct tunnels leading into or out of the basement of your home to or from particular locations, simply by noticing when you passed the stone column you set into the middle of the dirt. Speaking of cellars, clearing the ground and digging out foundations will let you build a cellar that is secure and neat-looking far more easily. It is a real pain in the heinie to have to dig out a cellar by removing the floor of your home and then later replacing it- you may find that you can’t get it quite the way you like again, or that trying to fit with the space you’re using above creates some very strange walls and nooks in your cellar.
These are all good reasons for foundations- but the best reasons come in when you are playing on a multiplayer server.
Oftentimes, other players will seek to ‘grief’ you- and they will do so by breaking or taking your stuff, and damaging or destroying the things you have built. While you can set up traps to stop them in your home, if you haven’t dug out beneath your floor you can’t build a trap to prevent someone tunneling into your home. If you have, however, you can place huge pitfalls, water to wash out incoming tunnels, and all sorts of unpleasant surprises for those who would destroy what you have built.
Finally, digging out and placing a foundation gives you an opportunity to set up a shelter for yourself on your construction site that is secure while you are still working on the walls and enclosure of your home itself. I do not doubt that many minecrafters have found themselves stranded at their buildsite without any form of ready shelter, and subsequently died and possibly even lost their build site (in the sense of being unable to find it again) simply because they didn’t have secure quarters, so to speak, where they were building.
If you’re building a foundation, however, it is simplicity itself to set up a little closed room with a bed and a chest that you can use as a hidey-hole during the night-time or while it is raining and the surface is still infested with monsters (thanks to a night rainstorm continuing into the day).
Because of this, I encourage you to set up a foundation- even if it’s something as simple as digging one block down into the dirt where you’re going to build and laying a block of cobble every so often.
Besides, you never know what you’ll find when you dig.