Baypole Screws
4.8mm
For bay windows, you should utilise bay poles (or a type of support like concrete pillars) for load bearing. The window frames alone are not enough, due to the Upvc bowing and warping.
Normally two bay poles are sufficient to connect a 3 sided bay. Bay poles are mostly present between the window joins. To connect the bay windows together, so they fit neatly in the bay and around the bay poles you use baypole screws. The screws are also used to connect the window sill to the window frame.
These screws come in different lengths ranging from 50mm to 90mm to suit your needs