Getting a Southern California Home Ready for the Rainy Season.
After seven or eight dry months, the first real storm of the season finds every gap in a house at once. A stucco crack that opened over the summer or a window that lost its caulk does not show while the weather is dry. Most of the rain here falls between November and March, so the weeks before the first storm are the time to look. These are the places we see water get in on Southern California homes, and what to check at each one.
Roofs and drains after a dry, windy fall
Santa Ana winds leave leaves, palm fronds and dust in gutters and on the roof. On a pitched roof that mostly means clogged gutters, which our seasonal checklist already covers. Flat and low-slope roofs need more attention. Many homes, patio covers and second-story additions here have one, and water only leaves them through a drain or a scupper in the parapet wall. If that opening is blocked, water sits on the roof and finds the next weak seam. Clear the drains, look for blisters or cracks in the roof coating, and check where the roof meets a wall, because the flashing there is where most flat roof leaks start.
Plenty of houses here have no gutters at all. That is fine as long as the ground below the roof edge slopes away from the house, which we come back to further down.
Stucco cracks and the weep screed
Hairline cracks in stucco are normal and usually harmless. Cracks you can fit a coin into, cracks that run from the corners of windows and doors, and cracks with a brown stain below them are different, because they let water reach the paper and framing behind the stucco. Fill those with an exterior patch or elastomeric caulk made for stucco before the rain, and paint over it if the color matters to you.
At the bottom of a stucco wall there is a metal strip called a weep screed. It lets water that gets behind the stucco drain out. The building code calls for it to sit at least 4 inches above soil and 2 inches above concrete, but over the years mulch, planters, raised beds and new patios often bury it. A buried weep screed holds water against the bottom of the wall, and that is how sill plates rot and baseboards on the inside swell without anyone seeing a leak. Pull soil and mulch back until the strip is visible along the whole wall.
Windows and sliding doors
Walk around the house and look at the caulk where each window frame meets the stucco. If it has cracked, pulled away or gone hard and chalky, cut it out and run a new bead. If the old bead along the bottom of the frame has small gaps left open, leave them open. They let water that got behind the frame drain back out.
Sliding doors and most vinyl windows have small weep holes in the bottom track that drain rainwater back outside. They fill with dirt over the summer. When they are blocked, the track fills during a storm and spills over onto the floor, and it looks like the door is leaking. Vacuum the tracks and clear the holes with a piece of wire.
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Grading, downspouts and planters
The ground next to the house should fall away from it. Over time soil settles, flower beds get built up and patios get poured at the wrong angle, and the water ends up running toward the foundation. On a slab home that can show up as damp carpet along an outside wall. On a raised foundation it shows up as standing water in the crawl space.
Put an extension or a splash block on every downspout so the water lands a few feet out, not at the base of the wall. Move planters and pots that sit against the stucco. If water collects in the same low spot after every storm, a small regrade or a drain may be needed, and it is easier to do now than in January.
Turn the irrigation controller off or switch it to rain mode for the season. Many local water agencies do not allow watering during rain and for 48 hours after it, so check the rules for your district.
What to check inside after the first storm
- Go into the attic with a flashlight the day after and look at the underside of the roof deck around vents, chimneys and skylights for dark or wet spots.
- Look at ceilings below flat roofs and in rooms under a second-story deck or balcony.
- Open the closets on outside walls and check the floor and the bottom of the wall, since nobody looks there.
- Check the drywall and the floor under every window, especially on the side of the house that faces the storm.
If you find a stain or damp drywall
Fix the source first. A ceiling repaired before the roof or the window is sealed will stain again in the next storm. Once the outside is closed up, the wet material has to dry or come out. Our article on the first 48 hours after a leak goes through that in order, and the water damage repair page shows what we do when drywall, insulation or flooring has to be replaced. Smaller jobs, like re-caulking windows or patching a section of drywall, are on the Services page.
If you own a rental, ask tenants to report water stains and damp spots right away and to send a photo. A stain caught after the first storm is a small repair. The same stain found at move-out often means the wall has to be opened.
Frequently asked questions
When is the rainy season in Southern California?
Most of the year's rain falls between November and March, often in a handful of storms. Some years the first storm comes in October and some years not until December, so plan to have the outside of the house checked by early November.
Can water get through stucco?
Yes. Stucco absorbs some water and is meant to let it drain out at the weep screed at the bottom of the wall. Problems start when cracks let in more than the wall can drain, or when soil, mulch or concrete cover the weep screed so the water has nowhere to go.
Why does my sliding door leak only in heavy rain?
Usually because the weep holes in the bottom track are blocked. In light rain the track holds the water; in a heavy storm it fills and spills inside. Clean the track and the weep holes first. If it still leaks, the seal under the threshold or the flashing around the frame may have failed.
Should I turn off my sprinklers during the rainy season?
Turn them off or use the controller's rain setting. Watering during a storm sends more water toward the foundation, and many local water agencies prohibit irrigation during and shortly after rain. Your water district's website lists its current rules.
Found a stain after the first storm? WestHills Contracting repairs water damage in homes and rentals across Riverside, San Diego and Orange County. Send us a few photos or call 951-587-7633.
