This paper expounds the definition and classification of the water-tightness and some influencing factors of the water-tightness indexes, analyzes the geneses of the rainwater seepage and the principles of antiseepage, and puts forward some measures for reducing the rainwater seepage.

The effect of the leakage with a window on the save energy of plastic windows;

The causes of external window leakage in residential engineering and its prevention and cure;

It introduces prevention measures for common problems in construction of aluminium alloy door and window from bad integral rigidity of aluminium alloy door and window、low-protection for production and leakage of door & window,and puts forward matters need attention in construction to ensure construction quality.