If you feel that your house needs roof windows you can install them for yourself without having to get professional do it for you. You will just need all the tools ready such as tape measures and hammer and you are good to go. The first thing you will need to do make the rafters in such a position that they can accommodate the windows. You should mark the center of the window and then remove the board to expose the roof covering. You should then get rid of tiles or slates by pulling them between the battens. Make sure you work on a stable surface to prevent yourself from falling. You should then continue removing the tiles until you get an opening that is good enough for you. After you have gotten the suitable space you are supposed to cut the battens that are near the side of the rafters. You can cut them on both ends so that you can get a wider opening. Once you have had enough space you can now place your roof window. Do this carefully and lock it in properly so that it does not fall. If you had removed extra tiles you can replace them when you are through to make your work look neat.