Flash the boot like any other roof penetration, and snap the tube into place—just make sure to align the hole between the ceiling joists...
Step by step:
- Mark the roof between two ceiling joists
- Turn the flashing piece upside down and mark the circle on the roof.
- Cut the hole about an inch larger than the circle.
- Nail the flashing to the roof deck, weaving it into the shingles. Use 4-5 nails per edge for wind resistance. Note: in areas with higher rainfall than LA, tuck the upper edge of the flashing under the roofing underlayment, shingle-style.
- Spread roofing cement along the top and side edges of the flashing.
- Continue shingling around the flashing.
- Apply silicone sealant to the light tube's interlocking collar.
- Paint the exposed metal black or whatever color you desire.
- Peel the plastic off the tube top.
—Eric Garcia is a roofing contractor in the LA area who posts a lot of videos to YouTube