Install headers (5) based on the position of the skylight finish groove and the interior finish material (6) and leave an appropriate gap for tolerances.

Make necessary supports before cutting roof rafters etc. and obtain expert guidance and professionally prepared plans both before cutting roof trusses and before cutting rafters. Install jack rafters etc. as necessary to keep the skylight adequately supported by the roof. If two or more skylights are to be installed together, see the installation instructions supplied with the COMBI-FLASHING.

Planning for the VELUX skylight.

Identify the appropriate location and cut an obervation hole (1) to determine the optimum position., obstructions etc. (2) consider positioning in relation to:
-Roofing material (refer to step 2a and 2b)
-Rafters and inside conditions.
Level, square and mark (3).
Cut rough opening (4).