Adding a Skylight

A friend is adding a skylight. A skylight installation will make daytime use of a dark room, or an inside bathroom more inviting and more natural. Of course at night it will seem like a black hole after getting used to the sun during the day.

The drawback to adding these sky windows to the center of a house is the amount of carpentry required to install and finish an opening from the ceiling to the roof. Your opening may be too small for the ceiling space available. This might result in too narrow of an opening from the ceiling to the roof. Not enough light will enter (too much will be absorbed by the walls) and the hole will be too small to look out of.

If the roof is too far away from the ceiling, or the room is too small, your best choice will be to install a tubular skylight. They usually have a dome on the roof, metal tubing from the roof to the ceiling to transmit the light, and a ceiling lens that looks like a recessed light fixture.

Be sure to do your homework when choosing one of these units. Some use an aluminum flexible tubing from the roof to the ceiling that is not bad, but it will not transmit nearly as much light as one with polished tubing. Others will have tall flashings on the roof that do a better job of preventing water leakage, especially when snow builds up against it. One model even has a mirror on the north side of the dome to direct even more light down the tube.

If you are going to hire a contractor to install any kind of skylight, make sure they use an experienced roof-man to install the flashing. Good roofers and carpenters that understand flashings are hard to find. Always go with the professional when there is or could be a problem with a roof. Improper flashing will allow the unit to leak within a few years. Usually there is no tar or mastic required to seal the flashing to the roof.

If a skylight ever does leak, do not slop tar around the unit. If you do, not only can the leak return within a year or so, the next guy to try to re-flash the unit will be unable to work if all the surrounding shingles are gooped together with tar. Amateurs with a bucket of tar can cause more problems than they solve. Tar may last a year or three, proper flashing will last the life of the roof.

Do it right the first time.