Skylights, Solar, and the Roof Penetrations Homeowners Add Themselves
Every hole cut in a roof is a place water can get in. Here is how skylights, solar mounts, and vents become leak points on a Rancho Cucamonga, CA roof, and how to add them without regret.
Every penetration is a deliberate hole in your waterproofing
A roof's job is to be a continuous, unbroken barrier against water, and every penetration through it, every vent, pipe, skylight, and solar mount, is a deliberate hole cut through that barrier. The roof can absolutely accommodate those holes, but only because each one is supposed to be sealed and flashed so water flows around it rather than through it. The trouble is that penetrations are where roofs leak far more often than the broad, open field, because a flat expanse of tile or shingle sheds water easily while every hole depends on a detail being done and staying done correctly.
This matters more than usual in Rancho Cucamonga because homeowners keep adding penetrations to roofs over time, often years after the roof went on. A skylight here, a solar array there, a new vent for a remodeled bathroom, each one is a new hole cut through a roof that was watertight before. When those additions are flashed and sealed properly they are no problem at all, and when they are not, they become exactly the kind of slow, hidden leak this dry climate is so good at concealing until the first hard storm finds it.
Skylights: great when flashed right, trouble when not
A skylight is one of the more common penetrations homeowners add, and it is a genuine improvement to a room when it is installed correctly. The catch is that a skylight is a large opening cut through the roof, surrounded entirely by a flashing detail that has to be done right and stay sound to keep water out. A skylight installed with proper flashing, integrated into the roof the way it should be, can serve for many years without issue. One installed by someone who relied on sealant instead of correct flashing is a leak waiting for the first real rain.
Skylights also age, and the older ones on a roof deserve attention during any inspection. The flashing around a long-installed skylight can corrode or loosen over the years, the same way other flashing on the roof does under this sun, and the skylight unit itself has a service life. When we inspect a Rancho Cucamonga roof with skylights, we read those details specifically, because a skylight is one of the spots most likely to be the source of a mystery leak on an otherwise sound roof. If you are thinking about adding one, the install detail is everything, and it is worth having it done by someone who treats the flashing as the real job.
Solar mounts: a roof decision as much as an energy one
Solar has become common on Inland Empire roofs, and it is a sound investment for many homeowners, but it is worth remembering that mounting a solar array means drilling a series of penetrations through the roof to anchor the racking. Done correctly, with each mount properly flashed and sealed, that is no threat to the roof. Done poorly, it is dozens of new holes in your waterproofing, and a leak under a solar array is genuinely difficult and costly to chase down because the panels are in the way of both finding it and fixing it.
There is also a timing question that homeowners often overlook. If your roof is anywhere near the end of its life, installing solar on it is a mistake, because when the roof eventually needs replacing, the array has to be removed and reinstalled to do the re-roof, which is an expensive extra step that good timing would have avoided. The sensible sequence is to sort out the roof first. If a re-roof is coming, do it before the solar goes on, so the panels sit on a fresh roof with a full life ahead of it. An honest inspection before a solar project answers that question directly, and it can save a homeowner a great deal of avoidable cost.
- Penetrations leak far more often than the open roof field
- Skylights are fine when flashed right, trouble when sealed with caulk
- Older skylight flashing corrodes and deserves an inspection
- Solar mounts are many new holes that all must be flashed
- A leak under a solar array is hard and costly to chase
- Replace a tired roof before adding solar, not after
Adding to your roof without adding leaks
The common thread through skylights, solar, vents, and every other penetration is that the addition itself is rarely the problem, the detail where it meets the roof is. A penetration flashed and integrated properly is a non-event, and the same penetration relying on a bead of sealant to do a flashing's job is a leak on a delay. So the single most useful thing a homeowner can do before adding anything to a roof is to make sure whoever cuts the hole treats the waterproofing detail as the actual work, not an afterthought to the fixture being installed.
It also pays to think about the roof as a whole before you add to it. Knowing the condition and the remaining life of your roof tells you whether now is the right time for that skylight or solar array, or whether a re-roof should come first so the addition sits on a roof that will outlast it. A quick, honest inspection before a project answers that, and it reads the penetrations already on your roof at the same time, since the existing vents, boots, and old skylight flashings are often where a current mystery leak is hiding. Add to your roof deliberately, with the details done right and the timing thought through, and the additions improve the home without quietly undermining the roof.
Whether you are adding a skylight, going solar, or chasing a leak around an existing penetration, the detail where it meets the roof is what decides everything. If you want those details read honestly before you add to your roof, that is part of what we look at on every inspection. Call 909-318-1571.
Ready to get it looked at? call 909-318-1571 any time.