Let There Be Light!

By James Dulley

August 12, 2016 4 min read

Dear James: My house is fairly small and I want to add a skylight to the living room to open it up. The problem is that there is an attic above it. Is there a way to still add a skylight in the ceiling? -- Steph J.

Dear Steph: Adding a skylight to a room can have an amazing impact on its decor and make it seem much larger than it actually is. You will be surprised at how the bright, natural sunlight will draw your family members into that room.

Although it is a little trickier to install a skylight in a room with an attic above it compared to a vaulted or cathedral ceiling, more than half of all skylights are installed this way. The actual installation of the skylight in the roof is identical, but you will have to build a light well from your ceiling to the skylight in the roof.

Before you start cutting holes in the roof, first determine the type of skylight (flat or domed, glass or plastic, fixed or venting) that you want. A fixed, domed, plastic one is probably the easiest to install and is definitely the least expensive option.

If you prefer a skylight that opens for ventilation, consider how it opens. Since it is up in a light well, it may be difficult to reach with a manual rod. Installing a model with an electric motor is most convenient. Make sure you have a simple path to run an electric line to it.

The size of the skylight is also critical for effective lighting and for aesthetic balance. If it is too small, it will look silly. If it is too big, it will create glare and result in too much energy loss. A rule of thumb is to multiply the square footage of the room by .045 to determine the proper square foot size of the skylight.

Go up on the roof and determine where you want the skylight to be located. Drill a hole through the roof at about the center of the skylight. Go into the attic. Use the hole as a reference only because the skylight location should be adjusted to match up with the rafters for proper support. Drill four corner holes up through the roof to show the exact location.

There are two light well designs you can use. A straight-walled light well is the easiest to build, but not the most attractive or effective. With this light well design, the opening in your ceiling is the same size as the skylight and the sides are straight for simplicity.

If you are somewhat handy with tools, a tapered light well is a much better design. The open area in your ceiling will be about twice that of the skylight area. It provides better distribution of the sunlight throughout your room and a better view of the sky.

No matter which design of light well you choose, it is extremely important to seal all the joints well with caulking. Silicone caulking is good to use because the temperature inside an attic can get quite high. Go into the attic and glue or nail several inches of rigid foam insulation on the sides of the light well. Don't leave any voids.

Once the light well is completed, the worst is over. Installing a skylight in the roof is straightforward procedure that is similar for most skylights. The key to a leak-free installation is generous use of caulking and careful fitting of the flashing and shingles.

James Dulley's weekly column, "Here's How," can be found at creators.com.

Like it? Share it!

  • 0