Adding High Lights

A tubular skylight brightens a dim space with sunshine.

Vampires aside, everybody has a built-in attraction to light. We humans are more like moths than bats, being naturally drawn toward illumination. In modern home design, this key factor influences window placement, house orientation and landscaping. But if your home was built in dimmer days or has a windowless room, hallway or closet, take heart: Natural lighting may be more attainable than you think. Tubular skylights offer a less expensive, less complicated and less invasive option than adding traditional skylights — and you can install them yourself.

That said, cutting a hole in your roof can be a scary proposition. Besides the obvious structural concerns, for many people, the biggest obstacle is a fear of heights. Always take precautions to be sure that you’re safe when scaling your house (see "Roof/Attic Safety Tips," below), and if you have any hesitation about working on the roof, hire a professional. If your main worry is preserving the integrity of your roof, tubular skylight manufacturer Solatube has you covered. Its unique flashing/flange system was designed to prevent leaks, and its simple, straightforward installation process was tailored for DIY success.

To show how a Solatube skylight is installed, we worked with Tom Sterns of Solar Midwest Inc., a Twin Cities distributor. Although Tom can complete the entire project in about two hours, a handy DIYer should allow a full day the first time (less for subsequent installations). Here’s an overview of typical installation highlights; if you decide to tackle this project, be sure to follow the detailed instructions in the Solatube kit.

How-to Steps
The project involves three areas: the interior space, the attic and the roof. First you’ll install the ceiling unit; next you’ll assemble the roof dome; then you’ll connect the two through the attic. (For homes that don’t have attics, Solatube makes skylights designed for cathedral ceilings.) The rooftop dome can be installed on a north-facing roof, but if you want the tube to reach a southern exposure – or if you have a steep-pitched roof – Solatube offers additional sections of tubes to extend beyond the kit's 4-ft. length.

On the ceiling where you plan to install the diffuser, use a stud finder to locate the ceiling joists. Bore a small hole at a center point between the framing. Bend a wire hanger to a 90-degree angle and insert it through the hole just past the bend. Twist the wire in all directions to check for clearance. Remove and straighten the wire; then insert it again so the wire protrudes above the attic insulation. Tip: Wrap bright-colored or reflective tape around the tip of the wire to make it more visible in the attic.

Next, go into the attic, locate the wire and verify that you have adequate clearance around it for the unit that you're installing. Using a plumb bob, determine the spot on the roof that is directly above the ceiling hole -- or as close to a direct line as possible. (Angle adapters on the tube-end assemblies allow for adjustments if the roof dome doesn't end up being straight above the ceiling diffuser.) Bore a 1/4-in.-dia. hole through the roof decking at a center point between the rafters. This marks the center of the roof-dome assembly. Poke a wire through the roof to help you locate the hole from above.

Now you can cut the circle in the ceiling. With the small hole as the center, mark a circle (10-3/4-in.-dia. or 14-3/4-in.-dia., depending on the model you have) and use a rotary tool equipped with a spiral bit or a drywall saw to cut the opening (photo 1).

Insert the bottom-tube assembly and check whether it aligns with the top-tube assembly. Adjust the angle adapter as needed. Temporarily secure the bottom assembly to the ceiling by rotating two of the built-in fastening clamps.

On the roof, center the flashing piece over the hole that you bored from the attic. Trace around the inner edge using a wax pencil to mark a circle. With a reciprocating saw or jigsaw, cut an opening that is 1/2 in. outside the marked line (photo 2).

Use a flat pry bar to loosen only the shingles along the higher half of the circle (photo 3). Keep the felt underlayment intact. Test fit the flashing to be sure that at least half of the flange tucks beneath the shingles along the upper side. The rest of the flange will sit on top of the lower shingles. The flange is angled so the upper rim will sit level.

Apply two continuous beads of roof sealant to the underside of the flashing, near the outer edges (photo 4). Set the flashing unit in place with the top half of its flange lying on top of the roofing felt; the bottom half sits on top of the shingles. Drive 2-in. flashing screws in each preformed hole and cover all screwheads with sealant. Secure the shingles over the top half of the flashing, sealing the old penetrations and adding a dab of sealant under the shingle tabs.

Insert the top assembly into the flashing hole (photo 5). Look down the tube to check whether the assembly is aiming toward the ceiling hole below and adjust the angle adapter accordingly. Apply foil tape as directed in the manufacturer's instructions and remove the protective film from the inside of the tube assembly. Insert the tube into the flashing, aligning the fastening holes; then drive the 1-in. screws to secure the dome ring to the flashing. Install the reflector in the dome as shown in manufacturer's instructions. Finally, set the dome on the dome ring, align the tabs (photo 6) and snap it in place.

The Solatube kit includes two 16-in. extension tubes, which can be installed between the top and bottom tubes to extend the unit’s span to 4 ft. (Additional tubes can be purchased if needed.) The sections telescope together with a minimum 1-1/2-in. overlap. Measure the distance between the ends of the top and bottom assemblies and add 4 in. to determine how long the tube assembly should be. The tube will be installed from inside the room. Before leaving the attic, be sure to carefully replace the insulation around the base of the tube.

Form the extension tubes by inserting tabs (photo 7), which are designed to yield a tapered tube for end-to-end assembly; then apply foil tape over the lengthwise seams. Remove the protective film from the insides of the reflective tubes and telescope the tubes together. To bond the seams, apply two 3/8-in. tube screws and foil tape to each joint.

Remove the bottom assembly from the ceiling, and remove its protective liner. Attach the bottom tube to the extension tube using two 3/8-in. screws and tape. Test fit the entire assembly into the top assembly, making sure the ring is flush with the ceiling. Remove the assembly and wrap the expansion-joint seal (included) twice around the upper end of the tube (photo 8). Slide the assembly back into the top tube (photo 9). Attach the ring to the ceiling with fastening clamps or 1-5/8-in. drywall screws. Snap the diffuser in place.

CAUTION: Once the protective film has been removed from the tubes, the reflective surfaces create intense glare. Do not look through the tube toward the sunlight until the diffuser is in place.

Tools/supplies list:
Wire hanger or heavy-gauge wire
Jigsaw or reciprocating saw
Rotary tool and spiral bit or drywall saw
Tape measure
Plumb bob
Wax pencil
Protective gloves and goggles

Anytime you’re working above the ground, follow these essential safety precautions:

  • Work on a dry surface (no dew, frost or rain).
  • Choose a calm (not windy) day.
  • Wear sensible shoes (no sandals or slippery soles).
  • Look out below (no people, pets or clutter under your work area).
  • Love your ladder (never accept one that is less than superb in both size and condition).
  • In the attic, walk, sit or lean only on framing members (never on the drywall).
  • Keep your cool (avoid working on the roof or in the attic when the temperature is high).