I believe the poster above is simply confused about the usage of the word "house". At least in the US, my experience has been that "house" is usually synonymous with "detached single family home." Pretty typical American example:

https://upload.wikimedia.org/wikipedia/commons/b/bc/Small_Si...

The next step down is a townhouse:

http://media.point2.com/p2a/htmltext/a2c4/c0e3/62d9/4e6d5930...

These are all but nonexistent outside of cities in the US, though.