It could be a playful attempt to say something like:
* "Casa de papa" - which translates to "Potato house" in English. This could be a silly phrase used to refer to a house made of potatoes, or a house with a lot of potatoes.
* "Casa de papá" - which translates to "Dad's house" in English.
However, without more context, it's impossible to know the intended meaning of "casa su papa."