Possessive Pronouns

Hi LuzM18, 

Thanks for your question! :) 

The overall meaning is the same (his/her house). However, you may prefer to use one or the other depending on the context and on the stress you wish to give to a specific term.
The "standard" order would be possessive adjective + noun (il mio cane = my dog). When you change such order, you often end up adding emphasis on the possessive adjective, stressing it.

Let's see the example below:
La nostra macchina è rossa. = Our car is red.
This is the "standard" structure and this phrase simply describes the color of our car.

But if you move the possessive adjective after the noun...
La macchina nostra è rossa. = OUR car is red.
This stresses the fact that OUR car is red, not yours, not hers, not his. 

Here is another examples:
Ho preso le tue scarpe. = I took your shoes.
Again, this is the standard structure, as I'm simply describing the fact that I took your shoes (the focus is on the shoes).

But if I said:
Ho preso le scarpe tue. = I took YOUR shoes.
The emphasis is on the fact that the shoes I took are yours. There is not much emphasis on the item I took, but it's rather on the owner of such item.

In most of the cases, you could technically use both versions, but the emphasis is different.

Let's see the example you mentioned:
La sua casa è bella. = His/her house is beautiful.
La casa sua è bella. = HIS/HER house is beautiful.
While in the first sentence you would be describing that the house is beautiful ,in the second sentence you are stressing that HIS/HER house is beautiful, perhaps more beautiful than someone else's house.

Let me know if I can help you further! :)