Is it proper grammar to say 'Andrew's house'?

Answer 1

If you mean "the house of Andrew" then yes, it's more than proper; it's perfect.

However if you meant the home of the Andrews family then it wouldn't be so good; it would be 'the Andrews's house'.

Interestingly (if you're a bit sad like me) there is an argument about if a noun ends in 's' like Andrews is it necessary to add on another 's' i.e Andrews's. I think the best thing to do is keep your text consistent. i.e don't mix things up as that will confuse the reader. Personally, I've never liked adding the extra 's' to the end of my name.

As a last bit of advice, read the possessives you write carefully. Sometimes using 'of' might sound better, sometimes it might not. In your example, Andrew's house sounds great but the Government's business doesn't sound to good (to me anyway) whereas the business of the Government sounds much better.

Answer 2

Yes, it is proper grammar to say "Andrew's house" to indicate possession or association with Andrew. The apostrophe followed by an 's' ('s) is used to show possession in English.