Skylight / July 9, 2018 / Delphine Demers
You will need to position and mark the opening on the ceiling after the skylight is installed. Take into consideration the size of the room and the amount of light you wish to bring in and select the size and position of the hole accordingly. Once the skylight is installed and the ceiling hole is cut its then a matter of connecting the two with the shaft which is typically constructed from 2x4 or 2x6 lumber. The angles involved typically require some tricky framing and is probably best left to an experienced carpenter. After the framing is completed the inside of the shaft is covered with wood or drywall and the attic side is insulated to minimize heat loss.
For example the optimum slope for a south-facing skylight in Columbus Ohio at 40º North latitude is 45º to 55º. Every skylight has a "shaft" which governs how much light is admitted into the room below. If all four sides are flared then the light is spread over a wide area. If your skylight has a shaft with perpendicular sides the light is focused straight below. If your skylights shaft is flared on only one or two sides then the light is sprayed in the flared direction. Ventilation If you wish you can have a skylight which also provides ventilation as well as light to your room. This allows you to release the hot air which collects at your ceiling.
If the room you intend to illuminate with the skylight has an open ceiling with no attic space above you can install the skylight without needing to construct a light shaft. This is by far the simplest installation and it offers the maximum amount of light and a view of the sky. For ceilings with an attic space above a light shaft must be constructed that connects the skylight to the room. Skylight shafts take one of three forms: Straight in which the shaft drops vertically from the roof to the ceiling and is the same dimension as the skylight itself. This type is the easiest to construct but because of its offset angle relative to the skylight offers the least amount of light.