Before starting to install your roof window, make sure you have the relevant safety equipment and correct tools to hand. It will make a big difference!
Once inside the roof space, you may find that your rafters are covered in plaster board or other covering. If this is the case it is important to establish the correct place in which to make a hole. By measuring from an external wall, you will be able to accurately determine the position of the window in relation to the outside.
Once an approximate position has been determined, it should be marked out accordingly.
A pilot hole should be cut out and removed to allow for more accurate measurement.
By inserting a rule either side of the pilot hole, the rafters can be located and marked out.
It is useful to work from the inside edge of a rafter, so as to minimise unnecessary framing out of the window.
When removing insulation, ensure that you take appropriate precautions by wearing a safety mask and, if necessary, goggles.
Removing a rafter
If it is necessary to remove a rafter, it is important that you consider the structural implications of doing so. If you are uncertain, we recommend you seek professional advice before proceeding further.
The bigger picture
It is better to remove the surrounding area of boarding so that you can see the big picture.
Be sure to support the area below where you are cutting the rafter.
... and secure support beneath the top of the rafter.
Cutting the rafter
You can then mark out, cut and remove the timbers.
Frame out the prospective opening to the correct height and width.
... to allow enough height for the reveals to splay back at the correct angle.