Amex Roofing blog
Rain can reveal leaks that went unnoticed through summer. After the storm, observations from the ground or indoors can help explain what happened.
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The pattern
NOAA’s April 1999 Climate of San Jose memo reports 82 percent of yearly rainfall between November and March, and a June through August total of 0.20 inches. The figures below describe the historical climate summarized in that memo. Significant rain can also fall outside those months.
The memo places most annual rainfall within these five months.
The historical summer total is much lower than the wet-season total.
The memo describes San Jose’s rain shadow and rainfall at roughly a quarter of the Santa Cruz Mountains’ total.
The memo’s annual range runs from near the bay to the southern edge near Los Gatos.
Local variation
The memo describes rainfall decreasing from south to north. Its 20-inch contour rings all but the northern part of San Jose, while the 14-inch contour runs roughly east to west north of the airport. These are historical annual averages.
The figures help explain differences in rainfall exposure within one city. An inspection is still needed to assess a particular roof’s condition and whether it needs work.
Roof details
Flashing directs water away from places where a roof meets a wall, chimney or pipe. Loose or damaged flashing can allow water to enter at those joints.
Rain after a dry stretch may reveal an opening that had not caused a noticeable leak. Wind or falling debris can also create new damage. The timing of a leak alone does not tell you when the problem began.
Our Santa Clara roof repair shows membrane work around skylights, vents and roof transitions.
Afterwards
Record what you can see safely from indoors or the ground after the storm. Photos and notes can help the inspector understand a leak that is no longer visible on the day of the visit.
Check ceilings under the roof, the tops of exterior walls, and areas around chimneys and skylights. Stains or dampness need investigation; roof leaks, plumbing leaks and condensation can all cause interior moisture.
Only enter an attic you can safely access. Use a flashlight from secure footing to look for moisture. Staining and rusty nail tips may reflect past leaks or condensation, so they do not establish an active roof leak on their own.
Once conditions are safe, look from the ground for signs of overflow or blocked drainage. Stay indoors during thunder and lightning. Do not climb a ladder or step onto the roof to investigate.
Leaks can come and go with changes in wind and rain. A dated note and photos help the inspector compare what you saw with the roof’s condition at the visit.
An inspection covers visible, safely accessible roof areas. Some leak causes need further checking. See what the inspection includes and how we provide a written work scope. Request a date and a one-hour arrival window; we will confirm by phone.
Book a free inspectionFor checks in any season, see seven roof warning signs worth checking. The written-scope FAQ explains what to ask for before approving work.
Amex Roofing is based in San Jose and handles roof inspections, repairs and replacements across the Bay Area, including Menlo Park, San Mateo, San Leandro, Fremont, Hayward and Milpitas.
Historical rainfall figures are from NOAA Technical Memorandum NWS WR-259, Climate of San Jose, Miguel Miller, National Weather Service Forecast Office, April 1999.
Request a date and a one-hour arrival window for a free inspection. We will confirm the appointment by phone.
