We usually say landlord for the owner of a house or a particular property. My question is whether calling the owner of the house landlord is shirk?
It is not shirk when it is understood that lord means owner. Examples of this are present in the Quran and Hadith where the prophets use the term, and obviously they can not commit shirk.
From the Quran in the story of Prophet Joseph عليه السلام:
فيسقي ربه خمرا
he will give drink to his master of wine
اذكرني عند ربك فأنساه الشيطان ذكر ربه
"Mention me before your master." But Satan made him forget the mention [to] his master
ارجع إلى ربك
Return to your master
From the ahadith of the Prophet Muhammad ﷺ:
أن تلد الأمة ربتها
When the slave woman gives birth to her mistress
إذا ما رب النعم لم يعط حقها تسلط عليه يوم القيامة، فتخبط وجهه بأخفافها
If the owner of camels does not pay their Zakat, then, on the Day of Resurrection those camels will come to him and will strike his face with their hooves.
وحتى يكثر فيكم المال فيفيض حتى يهم رب المال من يقبل صدقته
Till wealth will be in abundance so abundant that the owner of wealth will worry lest nobody should accept his Zakat