Balance daylight, room size, rafter layout, headroom and the manufacturer's pitch limits. The stated window size is not always the same as the structural opening.
Loft Windows for Conversions, Extensions and Attic Rooms
A roof window brings daylight and opening ventilation into loft conversions, extensions and rooms built beneath a pitched roof. MacBlair stocks windows for pitched-roof installation where opening size, roof pitch and covering type have been checked.
Choose the window and flashing as one system. Frame size determines the structural opening, while the roof covering and installation depth determine the flashing kit. Position also affects headroom, view, operation and internal lining, so set it out before rafters or battens are altered.
Weather the opening with the approved roof flashing components and connect the specified underlay collar or membrane. Maintain insulation using loft insulation around the reveal without blocking required airflow. Structural changes to roof timbers need a designed trimming detail.
Roof Windows FAQ's
Yes, most systems require a flashing matched to the window, roof covering, pitch and installation depth. Order these details together.
Some sizes may fit, but the opening still needs the manufacturer's clearances and structural trimming. Never cut a rafter without an approved design.
High indoor humidity, cold bridges or restricted airflow can cause condensation. Check room ventilation, insulation continuity and the internal lining detail.
It depends on the property, position, projection and local restrictions. Check Northern Ireland planning and Building Regulations before altering the roof.