LOWER FRAME OF COMPOSITE SASH

摘要

PROBLEM TO BE SOLVED: To provide a drainage structure suitable for drainage of rainwater or the like while contriving prevention of dew condensation by coating the indoor face of an aluminum lower frame by a resin lower frame and enhancing thermal insulation performance. SOLUTION: In a composite sash wherein a pair of double sliding window screens 10 are housed in a window frame 1 provided with an aluminum frame 2 mounted on a window opening part A and a resin frame 3 covering the indoor side exposed part of the aluminum frame 2 and a drainage opening 73 for draining dew condensation water or the like of a lower frame part communicating with the hollow part 22d is provided on the upper face of the aluminum lower frame 22, a resin cover frame 43 constituting a resin lower frame 32 is detachably mounted on the lower outer rail 22a of the aluminum lower frame 22 and a part of the inner face part of a lower inner rail 22b and a drainage device 70 is mounted on the drainage opening 73 of the aluminum lower frame 22 through the resin cover frame 43.