Sforno on Genesis 11:3/ספורנו על בראשית י״א:ג׳

1הבה נלבנה לבנים, now they wanted to build permanent housing for themselves and pens for the flocks and herds. This was a common consensus, as we know from the Torah describing their speaking to each other as ויאמרו איש אלך רעהו, “they said each to his colleague.”