Can "Is this your house?" and "Is this your own house?" both mean the same as in "Do you own this house?"
Similarly, "I designed my house." and "I designed my own house.", do they mean close to "I myself did the designing of my house."?
Looking forward to your help. Thank you.
You would only use 'own' if you specifically wanted to determine ownership, you would use the first question if you are happy just to find out if the house is the place that they normally live, but either way the difference is small.
The difference between 'I designed my house' and 'I designed my own house', you would only include 'own' if for some reason you need the listener to be aware that your definitely talking about the house you live in now, but again the difference is very small.