Get Standard Skylight Order Form - Crystalite Inc

As a rule of thumb, the skylight size should never be more than 5% of the floor area in rooms with many windows and no more than 15% of the room's total floor area for spaces with few windows.

One of the most popular types of skylights are the ventilating skylights. These types of skylights are capable of providing a significant amount of additional light to any room wherever you want it. Essentially, this is going to be adding a new window onto the roof of your house.

You'll need numbers from both the outside and inside of the skylight. That means the first numbers will be found on the roof. Once you're up there, measure along the side of the skylight where the shingles meet the flashing, width first then length. Next, measure the height of your skylight or curb.

Skylight sizes are based on roof truss spacing. The majority of homes have trusses installed on 24” centres. The inside rough opening of a skylight to fit between your trusses, and not require removing a part of the truss, would be 22.5”.

For rectangular fixed or vented skylights with flat tempered glass, standard sizes vary from 14-72 inches in width and 16-96 inches in length. Average skylights can vary quite a bit in weight but average around 60 pounds and can go all the way up through 150 pounds.

It is typically framed with 2x4s, insulated like any interior wall and finished on the inside with drywall or other material. The light shaft may be vertical or flared–wider at the bottom than the top. A flared light shaft is a little more difficult to frame but will admit more light.