Sticking widow blinds

We first enountered problems of the window blinds not returning after being in the position to cover the windows for long periods several years back. OK you can adjust the return spring.

BUT how to avoid it happening and keep out the hot Spanish sun for days on end?

We bought some carpet underlay; The sort with a silver sirface and foam backing

This was cut to fit inside the window fittings (latches, stays etc)

Then simply put this in place at anytime you wish to keep out the sun (camping in hot sunny places, Laying up over winter.......) After use they mat be stored flat under the bed mattress ready for next time