Should I extend my house upward or knock down and build from scratch?

Question

I want to expand my house upwards by adding another 1000ft² level. I'm told that knocking the house down and build from scratch would be easier than dealing with all the issues. In my area I've been told construction costs 200/ft² which would be rather expensive for a new 2000 ft² house. What do people think?

Answer 1

I've thought about doing the same thing (adding on an upstairs to my house). One of the simple problems is permits; the inspection offices want to deal with things they know, and building above an unknown.

Basically, your support comes from below; the new floor rests on the floor below, and the floors below on the foundation. If you need stronger walls, you need to start tearing things out (eg, drywall) so you can bulk them up, and you can't just add new load-bearings walls without putting some sort of footing in below them; that's near impossible in most construction.

There are typically tables of how much load a room has to be able to support in a given area; 30lb per square foot is pretty typical, but you have to remember that an unevenly loaded area often requires heavier duty walls to deal with the torsional and lateral forces.

I still haven't given up on putting a second floor on my house, but I know that to be able to do it, I'm likely going to have to strip the walls back to see what there is, which means either from the inside (plaster walls) or outside (wood siding), either of which is going to suck to replace.

Answer 2

I'd have to agree with @Tester101 that without actually seeing the site, there is no real way to tell you if what you plan can be done, but one data point: my brother looked into adding a floor to his house, and the estimate he got was a lot more than he paid for the house 5 years earlier. I can easily believe that it would be cheaper in the long run to knock it down & rebuild, and would probably have much higher resale value.

Answer 3

You could build over, rather then upwards using a metal frame, then just connect the two independent structures at the stairs. You will need a very good engineer, but at least there will be very few unknowns as the new frame could even sit on separate foundations outside of your current foundations.