What's that mate? Time travel? Well, the basic problem, as I see it, is the linear flow of causality. Some smart arses might bang on about the build-up of entropy but you don't want to get bogged down in all that. You see, you've got your cause and effect, and if you start mucking about with 'em and getting 'em in the wrong order, you gonna have yourself a right old picnic.
I'm not saying it can't be done, mind. Problem is, if you don't know what you're doing you can end up ripping a hole in the space-time continuum and that can be pricey, if you get my drift. Take more than a bucket of plaster and a lick of paint to set that mess right.
But that's by the by. The real problem is you need a lot of elbow room if you want to build a time machine, 'cos you need to warp space; and to warp space you need mass - a lot of mass. How big is your gaff then? Yeah? You see, that's a problem because the average semi-detached in Chiswick isn't really going to cut it, not even if you've got a garage. Not even if you knock through to next door. You're gonna need an area as big as... ooh... Wales, at the very least.
Then there's the planning permission. Trust me, that's going to be a bloody nightmare, 'cos you can bet the neighbours will have something to say about it. Bleeding nuisances. You'd better be ready to grease the right palms, know what I mean?
Not that I'm trying to put you off, you understand. I mean, it's doable. Tell you what, I'll make a few calls and get back to you with an estimate, but if I were you I would seriously think about going for a swimming pool instead.