Meaning:

“房子”is “house,”“塌” means “collapses” and “了” is a marker for perfect tense. A term originated from an interview in Korea when an old lady said, “I saw a house collapse over there and I went over to see what was going on. But I found out that it was my house.” So this expression means that you look on other people’s incidents or embarrassment for fun, but it turned out that it is your own backyard that was on fire.

When used in fandom circles, it refers to a fan that is about to watch the juicy news about other people’s favorite idols, but the news turns out to be about his or her favorite idol. In another scenario, “house” is a metaphor for “spiritual support” to fans. When their idols are in a relationship with someone and their fans were sad, it is as if their house had collapsed.

Example:

A：你家爱豆最近怎么样？

nǐ jiā àidòu zuìjìn zěn me yang?

How’s your idol these days?

B：别问了，他谈恋爱了。粉丝伤心死了，房子塌了一片。

bié wèn le, tā tánliànài le. fěnsī shāngxīn sǐ le, fángzǐ tā le yī piàn.

Don’t bother to ask. He’s in love. We fans were so sad that our house had collapsed.