All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
In At-Targheeb wat-Tarheeb, Imaam Al-Munthiri said about the first Hadeeth that it is not authentic. It was narrated by Ibn Abi Ad-Dunya on the authority of ‘Ammaar ibn ‘Aamir who is a Taabi‘i (Follower). So, the Hadeeth is a Mursal Hadeeth and cannot be attributed to the Prophet, sallallaahu ‘alayhi wa sallam.
The second Hadeeth was narrated by At-Tabaraani in Al-Awsat and Al-Bayhaqi in Shu‘ab Al-'Eemaan, but As-Suyooti, Al-Munaawi, and Al-Albaani classified it as Dha‘eef (weak).
The two Hadeeths are not authentic. However, scholars stated that building is dispraised when it is done for any purpose other than purposes of the Sharee‘ah (Islamic law), that leads to abandoning an obligation or doing a forbidden act, or exceeds one’s need. This is because the worldly life is not an eternal abode.
Allaah Knows best.