I once forgot to eat for 12 hours. Sometimes, people will have entire conversations with me. After I give them a series of monosyllabic answers, I inevitably look up and ask "wait...what did you just say?" I'm not crazy, I'm spacing out. And if you're going to write successfully, you're going to need to learn how to do it, too.
Alone in My Head
The world is never going to shut up for you. It doesn't matter if you crawl into a bunker and lock the door, the world is still going to find you. It's going to intrude no matter how carefully you plan your day and no matter how many rules you make for your household. Closing the door may be symbolic to you, but life is always going to intervene.
You have to master the art of spacing out. You have to be capable of sitting in the middle of Grand Central Station with a smartphone and write your novel, if that's what it takes. Because sometimes, that is what it's going to take. Sometimes, you're going to have to write while the kids are screaming, phones are ringing, the TV is going and someone's in the background asking a bunch of inane questions about the contents of the refrigerator. Life is like that. The writer has to learn how to leave this very busy, noisy world...and step into the one they're creating on the page.
You have to learn the technique of spacing out.
Turning Off the World
Spacing out isn't easy. You have to focus on the story in front of you and only that. There are going to be a lot of distractions in your ear, but you've got to focus on what's on the page. It is a skill that can be learned; it just takes concentration. Practice it by turning on some music or the television when you're writing. Start out at a low volume, and try to write. Focus on the words and tune out the noise until it's just that: dull noise in the background that doesn't mean anything. As you feel more comfortable, meaning more focused, increase the volume.
Keep practicing until you're able to shut out the world and live solely on the page. It's not going to work 100 percent of the time; there will be moments when a jarring noise or a loud shout will break your focus. But once you know how to let the noise fade into the background, you'll be able to work well anywhere.
However, I would caution you to set reminders so you don't forget to eat.