VELUX Underfelt Collar - BFX 1000
The BFX Underfelt Collar ensures a fast connection between the VELUX Roof Window and the roofing felt/membrane. It helps to protect against drafts and wind driven rain and snow around the window installation.
It comes as one piece making fitting easy, especially around the window corners.
The tranverse drainage gutter included also prevents any water ingress around the roof opening caused by missing or broken slates or tiles above the window.