VELUX installation products

The range of VELUX flashings and installation products make the professional installation of your roof windows quick, simple and safe. All original VELUX installation products are compatible to ensure that your roof window is weathertight and safe connected to the roof construction and has an excellent finish on the inside.

Watch the installation

Installation products

Original VELUX
Underfelt collar BFX
Water drainage
Insulation frame
Vapour barrier
collar BBX
Interior lining
Lining frame
kit LSG
Fit exact window
dimensions and
connect perfectly
to your roofing material
Pleated underfelt
collar forms a
tight seal between
roofwindow and
your felt underlay.
drainage gutter
ensures safe
water drainage
from above the

Insulation frame
with flexible foam for a tight and secure fit to the roof construction.
Vapour barrier
collar, including assembly tool for a vapour- and airtight solution.
Prefabricated linings
for easy and airtight inside completion. Includes vapour
barrier collar.
adjustable steel
frame for fast and
easy framing for
your on-site lining. Includes vapour
barrier collar.

Standard or recessed installation

VELUX New Generation roof windows offer two installation heights, standard or recessed. The recessed installation provides a sleek, streamlined appearance, sitting 40 mm deeper in the roof structure, and provides architects with greater design flexibility.

To ensure maximum probability that the declared energy performance is achieved, we recommend installation of the roof window with flashing for recessed installation. When installed with the appropriate VELUX insulation collar, recessed installations result in saving more energy.

Standard installation


Remember to order the right flashing for your window installation

Your new VELUX roof window must be installed with a flashing. VELUX flashings are precision-made and designed to ensure a watertight seal between the roof window and the roofing material and ensure safe and effective water drainage. You can choose among different versions and combinations of flashings to match your roof window and roofing material.

Extra insulation and protection

Optimise your new roof window to ensure an energy-efficient and durable installation. You can choose the frame insulation product BDX, which ensures proper insulation between the roof construction and the window frame, and the pleated underfelt collar BFX, which ensures a flexible and tight connection between the underfelt and the window frame. The drainage gutter ensures that water from the underfelt above can drain away from the window.

Download prices and sizes for extra insulation and protection of your roof window
B1: Insulation frame
B2: Drainage gutter
B3: Pleated underfelt collar

Excellent interior finish

Use VELUX linings to optimise the finish in your room. We recommend the pre-fabricated VELUX linings LSB/LSC/LSD with sharp lines to match contemporary styles. The linings are made in water- and moisture-repellent materials with a white finished surface treatment. The unique design creates space for extra insulation material to prevent thermal bridges. Alternatively, VELUX kit for lining LSG forms a perfect structure for shaping your own plasterboard lining. The unique design creates space for extra insulation material to prevent thermal bridges. Both VELUX linings and VELUX kit for lining are delivered with VELUX vapour barrier collar BBX, which is 100% vapour-tight and prevents condensation. Download prices and sizes for interior finish.
C1: Lining frame LSG
C2: Vapour barrier collar BBX
Interior lining
Excellent and perfect interior finish

Professional information

Are you an installer or a dealer – follow the tab Professionals at the bottom of the page to find more information about the product such as CE marking, installation instructions, spare part overviews, test reports and specifications.