'grandmother's house' or 'grandmother house'?

[wotcha]

I'm going to my grandmother's house/ grandmother house.


Which is correct and why?
:roll:

 

[freezeframe]

I'm going to my grandmother's house/ grandmother house.


Which is correct and why?
:roll:

grandmother's house

Because it's a house that belongs to grandma.

 

[5jj]

The first one is correct.
Grandmother's house is a house belonging to her.

Not necessarily. If she lived in a rented house, we'd still call it Grandmother's house.

'Grandmother house' could be a house named 'grandmother' like 'The [STRIKE]w[/STRIKE] White [STRIKE]h[/STRIKE] House'

Highly unlikely.

I realise that you are just trying to build up posts so that you can post a link to your survey, but please don't make up answers that could mislead people.