Our house is situated. There are some verbs which are mostly used in passive voice. You can find a bigger list here.
http://sdhanel.com/Verbs/voicestefl.html
With the verb situated, and those used mostly in passive voice, there isn't an agent doing the action or it isn't important. The second sentence would read that your house did an action 'Our house situated... something'. The house isn't able to situate anything. Although a house can do other actions such as, protect, fall down, etc. but it can't situate. I hope this helps!