Architectural walkthrough using Timesplitters
The game engines created for first-person shooters are also ideal for 3D architectural walkthroughs. Although I couldn't find any that had been specifically adapted for that use, I did find that the mapmaker provided with the Playstation 2 game Timesplitters: Future Perfect was sufficient for creating a customisable three-dimensional house to explore.
Even if you have the Timesplitters game, you probably haven't played with the mapmaker because of the exceedingly light documentation provided in the manual. To remedy this, I used the mapmaker FAQ from the ever reliable gamefaqs.com. Since you're building a house and not a scenario for battle, you'll find you can ignore large swathes of the document, but don't miss the juicy bits.
The key to building indoor and outdoor areas is to realise that your "blank canvas" is actually solid rock rather than empty space (- you're more like a sculptor than a painter). So, if you place a tile denoting open area, then you'll need to add open area tiles in all the levels above to be able to see the sky. In addition, these tiles must all be of the same type, eg. large open above large open, and small open tiles above small open.
Although there seem to be a lot of tile types to choose from, most are too specific to be used in creating a copy of a real house. Instead, use mostly small corner and small t-junction tiles to create whole rooms. Whilst you can't customise the textures used, you can specify the lighting type and colour, for example flickering lights might denote a room with fluorescents.
It's important to start building on the correct level, as you can't move whole floors after you've started. You only get 5 floors to play with, and the top floor will not have a roof. So, perhaps start by building the top (roofed) floor of your building on the second from top level, and work down from there.
Stairs can be tricky, because you can't place stairs directly above another set of stairs. If you creatively offset them slightly, then this shouldn't be too much trouble.
Finally, leave the doors and windows till last. Whenever you move a tile, the attached doors and windows are lost, so it'll save work if you leave them till the rest of the floor plan is set in stone.
I'm sure that there are some PC-based first-person shooters which would provide a more customisable end result, but I doubt that they'd provide such an easy tool for its creation.