What is polycarbonate secondary glazing?

Polycarbonate is tougher than glass and can be fitted over wooden windows as secondary glazing with magnetic strips. It is hard to spot the polycarbonate glazing as you can see from the picture below. If you would like to know more read our  Polycarbonate glazing factsheet and you might also be interested in our DIY Secondary Glazing ‘How to’. It is really easy to install, so you might want to have a go yourself.