How to Install a Skylight Tube

Before starting this project:

Use caution when working in attic spaces, and only step on plywood or joists. Drywall will collapse under a person's weight, resulting in a fall and possible serious injury.

Double-check measurements before making cuts in the roof.

This project is best completed with the help of a second person.

Determine Placement of Skylight Tube

From the attic, find a place to install skylight tube between ceiling joists. (It may be necessary to cut out a section of plywood flooring to gain access to drywall ceiling.) Push a nail or screw in center of desired location. View it from inside the room to make sure placement is good. When proper place is determined, hang a plumb line from room to nail/screw. Make a mark when the plumb line is lined up. With a hammer, drive a large nail through roof to mark placement. If a straight tube placement isn't possible, tube can be fitted at angles to accommodate stairs/dormers, etc. Test-fit tubing to determine proper placement of roof hole. Tip: A plumb line can be made out of a piece of string and a washer.

Cut Hole in Ceiling

Use the hole template from kit and a pencil to draw a circle to appropriate size of skylight tube. Cut around circle using jigsaw (Image 1, 2). Tip: It's helpful to have someone underneath the circle to vacuum dust with shop vac and to catch drywall circle.

Cut Hole in Roof

Climb up on roof using ladder placed in a sturdy location. Using center point marked with the large nail used in step 1, use template and a piece of chalk to draw circle (Image 1). Cut along circle with a jigsaw (Image 2). (In the case of this installation a small hole was cut to accommodate a plug for jigsaw, but this is not necessary.) Tip: Wear shoes with good treads like hiking boots, work boots or trail running shoes when working on a roof.

Assemble Top and Bottom of Skylight Tube

Using foil tape or duct tape, assemble top and bottom sections of skylight tube (Image 1). Pieces in kit should be labeled. If an extension is necessary, do not assemble it at this point.

Install Top (Roof) Portion of Skylight Tube

Use claw of hammer or pry bar to gently lift up shingles above cut hole and remove nails in order to accommodate plastic flashing piece that comes with kit. Using a caulk gun apply roofing cement liberally to bottom side of plastic flashing. Turn over and slide under loose shingles; line hole in flashing up with hole cut in roof. Secure with flashing screws and washers in marked locations. Slide top of tube into opening from roof (Image 1). Have assistant work inside attic to help with lowering tube into position (Image 2). Tip: For additional waterproofing, put a dab of sealant under each washer and around outside perimeter of plastic flashing.

Install Bottom (Ceiling) Portion of Skylight Tube

Screw ceiling trim piece into hole cut in ceiling (Image 1). In the attic, lock bottom portion of skylight tube into trim piece (Image 2).

Measure and Cut Extension Tube

Use tape measure to determine height of gap between installed bottom (ceiling) tube (Image 1) and top (roof) tube (Image 2). Transfer measurement to extension tube piece, adding 6 inches total for a 3-inch overlap on each tube. Cut with tin snips (Image 3).

Install Extension Tube

Peel off protective coating and line up extension tube with ceiling and roof tubes. Wrap extension piece on outside of tubes and use adhesive strip provided in kit to secure. Tape seams with duct tape.

Install Dome and Diffuser Lens

Line up dome onto roof piece and secure with screws (Image 1, 2). Do not over-tighten screws and crack dome. Apply an exterior silicone over dome screw heads with caulk gun. Inside room, click diffuser lens into place. Tip: Keep an eye on skylight tube during first rain to make sure waterproofing was successful. If not, more roofing cement, flashing and/or silicone may be required.