Kitchen islands are all the rage in big homes, but why would you want one in your kitchen? We spoke to kitchen design expert Ralph Mooney about the feature everyone's talking about.

Q: Mr Mooney, thanks for your time.

A: Thanks for giving me the opportunity to speak.

Q: So kitchen islands are very popular at the moment. Can you tell us some of the good points about kitchen islands?

A: Well, there are a lot of good points. But the most obvious thing is that a kitchen island provides extra storage space and extra work space. If you've got a kitchen that's big enough, an island makes sense. But of course it's not for everyone and there are some drawbacks too.

Q: Like what?

A: For instance, if you've only got a small space to work with, obviously an island kitchen could just impede your work instead of helping it. But that doesn't stop some people trying to shoehorn an island in there. And even in a decent sized room you've got a bloody big island in the middle of it, which isn't always the best thing for the space.

Q: So if you're thinking of installing a kitchen island, what sorts of things should you keep in mind?

A: If you want a sink in your island, the plumbing's going to be tricky, so that's one of the first things to keep in mind. It's a bit tricky to explain, but basically it's hard to get the venting right. You've got to vent any sink to keep the pressure right - if there's not enough pressure, debris builds up. If there's too much pressure, you can actually get gas coming up through the sink, which is nasty. It's pretty easy to vent a sink that's next to a wall. But venting an island sink is much trickier. That needs a special type of venting. It's best to talk to your plumber about how to do it.

Q: How does an island bench affect your kitchen in terms of space?

A: Well, they can be really good in open-plan areas because they create a kind of divide between the work area and the entertaining area, kind of acting like a wall. It's your Clayton's wall - the wall you have when you're not having a wall. Usually you'll position the island to face the entertaining area so that you can talk to your guests or keep an eye on your kids while you're cooking. You can use it as a servery too and a lot of people install a breakfast bar, so it acts as kind of a surrogate kitchen table.

Q: Mr Mooney, thanks for your time.

A: My pleasure.