3 sentences

1. 他背着妻子存了一点私房。

   tā bèi zhe qī​zi cún le yī​diǎn sī​fáng.

   He saved some private money behind his wife's back.

   Source: Dong Chinese Dictionary

2. 这几间正房都是他家的祖传私房。

   zhè jǐ jiān zhèng​fáng dōu shì tā jiā de zǔ​chuán sī​fáng.

   These main rooms are his family's ancestral private property.

   Source: Dong Chinese Dictionary

3. 这些旧房子都是祖传的私房，不属于公家。

   zhè​xiē jiù fáng​zi dōu shì zǔ​chuán de sī​fang, bù shǔ​yú gōng​jiā.

   These old houses are all ancestral private property and do not belong to the state.

   Source: Dong Chinese Dictionary