TT #752 · Parashas Ki Seitzei · Seventh Aliyah · Passuk 25:09
Then his yevamah shall approach him in the presence of the elders, and draw his shoe off his foot, and spit in his face, and respond and say: “Thus shall be done to the man who will not build up his brother’s house.”
Torah Temimah points to Yevamot 10b / 11a.
TT lemma: אֶת בֵּית אָחִיו.
בַּיִת אֶחָד הוּא בּוֹנֶה וְאֵינוֹ בּוֹנֶה שְׁנֵי בָּתִּים.
English: He builds one house and does not build two houses.
On the daf / in context: The language is used to prohibit taking both the yevamah and a co-wife.
Derash limiting the yavam to one house.
A yavam may not take both a yevamah and her co-wife in yibbum.