Sahih Muslim 777
Sahih Muslim · Book 6: The Book of Prayer - Travellers · It is recommended to offer voluntary prayers in one’s house although it is permissible to offer them in the masjid
Ibn 'Umar reported Allah's Apostle (ﷺ) as saying:
وَحَدَّثَنَا ابْنُ الْمُثَنَّى ، حَدَّثَنَا عَبْدُ الْوَهَّابِ ، أَخْبَرَنَا أَيُّوبُ ، عَنْ نَافِعٍ ، عَنِ ابْنِ عُمَرَ ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " صَلُّوا فِي بُيُوتِكُمْ وَلاَ تَتَّخِذُوهَا قُبُورًا " .
Pray in your houses, and do not make them graves.