Underfelt Collar and Transverse Drainage Gutter.
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.
- Can be used in all roofing constructions in roof pitches between 15° and 90°
- Is well suited for roofs with or without battens
- Can be used for both ventilated and unventilated constructions
- The underfelt collar is pleated and can be easily dressed round the battens of the roof, irrespective of the batten distance
- Special diffusion open underfelt of polypropylene and galvanised steel drainage gutter