California's rainy season can be tough on commercial roofs. While we’re usually known for our sunny weather, the winter months bring heavy downpours that can put a lot of stress on your roof. A small issue on a dry day can turn into a major repair when a storm hits. For facility managers and property owners, this means one thing: now is the time to get your roof ready.
A well-maintained roof protects everything beneath it. Your equipment, inventory, and operations all depend on that watertight barrier overhead. When water gets inside, repair costs add up fast. Preparing before the first storm will make sure your business is ready for the season and preventative maintenance can extend your commercial roof's lifespan by years and help you avoid costly surprises. Routine upkeep catches small issues before they become major problems, improves energy efficiency, and gives you peace of mind when storms arrive.
Rain doesn’t show up quietly on a commercial roof. It finds the places where water already moves slowly, pushes against edges that softened over time, and settles into any spot that was overlooked during the dry months.
Commercial buildings often have flat or low-slope designs because they're cost-effective and provide space for equipment. But water doesn't naturally run off these roofs the way it does on a pitched surface. Even a slight dip or settling can create spots where water collects after a storm. Once pooling starts, that standing water becomes a constant pressure point on your roof. Flat roofs need smooth drainage. A residential roof with good slope might forgive a clogged gutter for a while. Your commercial roof won't. When drains get blocked by leaves or debris, you're looking at hundreds of gallons with nowhere to go. That’s when you’ll start to see leaks.
Wind is another common concern for California business owners. A strong storm can lift a loose corner of the membrane or shift debris toward drains. It also pushes water sideways, so areas that stay dry in gentle weather start to see moisture. Add in the HVAC units, exhaust vents, and other rooftop equipment most commercial buildings depend on, and you've got multiple points where water wants to find its way in.
The real risk isn't usually the storm itself. It's the combination of putting off maintenance and then the heavy rain that causes costly problems. A small issue you could fix for a few hundred dollars in October becomes an emergency repair in January.
The best time to find roof problems is before it starts raining. If you walk your roof now, you'll be able to catch issues while they're still easy to fix. This doesn't need to be a complicated process, just thorough and consistent. The goal is to understand the current condition of the roof, catch anything that might invite water in, and make sure drainage paths are clear.
Clear every drain, gutter, and downspout. Leaves, branches, and debris accumulate over dry months and cause backups when storms hit. Look for areas where water pooled after the last rain because those spots will pool again.
Look for cracks, blistering, or tears in the membrane. Pay close attention to seams and joints where different sections meet. If your roof has a coating, check for areas where it's worn thin or peeling.
Look at the metal trim around seal joints and your roof's edge. That’s called flashing, and it’s there to prevent water from seeping into gaps. It should lie flat and tight against the roof surface. Loose or rusted flashing lets water in.
Your HVAC units, vents, pipes, and skylights should have tight seals around their bases. Look closely for gaps, cracks, or deteriorated caulking.
Water stains on ceilings, warped doors or windows near the roofline, and musty odors are all signs of leaks that your building is already struggling with.
Take photos and notes to keep track of changes over time. These records can help with insurance claims if you ever have a major problem.
The roofs that hold up best are the ones that get the most attention. Here are some best practices to keep your roof in top shape throughout all the seasons.
Debris clogs drains, traps moisture and can puncture membranes. Try to clear leaves, branches, and trash regularly. If trees overhang your building, trim them back before branches become a problem.
Don't wait for your scheduled inspection if severe weather hits. A quick walk after high winds or heavy rain can catch new damage while it's still minor.
HVAC units, exhaust vents, and other equipment need regular servicing anyway. When your technicians are up there, ask them to check the roof surface and seals.
Maintenance logs make a difference. Photos, dates, and repair notes help with warranty coverage and create a clear record of how the roof has been cared for over time.
There’s some maintenance you can handle by yourself. But issues involving the membrane, flashing, or drainage design need a qualified commercial roofing team. Catching problems early means you can schedule professional repairs on your timeline.
Regular inspections prevent problems, but only if they actually happen. Put roof care on the calendar like any other critical system. It’s a good idea to start with a professional evaluation of your roof's current condition and expected lifespan. This tells you how aggressive your maintenance schedule needs to be. Then, create a care calendar based on the condition of your roofing system.
Here’s a good place to start:
Monthly: Visual checks for damage or debris
Quarterly: Drainage clearing and equipment seal inspections
Twice yearly: Comprehensive inspections before and after the rainy season
Annually: Professional contractor assessment
Routine care costs less than emergency repairs. Setting aside funds each year will help you handle small repairs quickly without the stress. Waiting too long can turn minor issues into more expensive problems.
Most building managers don't think about paperwork until they need to file a claim, but by then, it's too late. When water damage happens, one of the first questions your insurance or warranty provider will ask is how the roof was maintained. With comprehensive documentation, you can answer that question without hesitation. It shows a clear pattern of care, not just a reaction to problems after they appear.
The simplest way to build reliable documentation is to treat every inspection like a record worth keeping. Take photos even if everything looks fine and note the date. If a repair is made, save the paperwork and add a short summary of what was done.
A typical record should include three things:
This creates a full history of your roof, and it will help you understand how the system is aging. More importantly, it gives you proof of proper maintenance if you need to file an insurance or warranty claim.
Some roof care steps are simple enough for the building team to handle, but certain issues are best left to a trained commercial roofing professional. Specialists can spot early signs of trouble that are hard to see during routine walkthroughs, especially around drainage systems, aging seams, and areas that were patched in the past.
You need someone who understands commercial buildings, not a company that only works on residential shingles. The materials are different, the scale is different, and the stakes are higher. This is your business after all.
Start with their track record on commercial properties. Ask for references from buildings similar to yours. A professional with experience on flat or low-slope commercial roofs will spot issues a residential specialist might miss. The right partner also thinks beyond repairs. They should offer maintenance guidance that helps prevent small problems from turning into expensive ones. It is also worth asking how they handle emergency calls. When a storm hits and a leak shows up, you cannot wait several days for a response.
Your commercial roof will hold up for decades if you give it the proper care and attention. And that doesn't mean you need to spend a lot of time or energy worrying about your roof. The easiest way to stay ahead of the rainy season is to bring in people who work on commercial roofs every day and know exactly where trouble tends to start.
The team at Citadel Solar & Roofing will take a close look at your roof, point out what matters, and handle the work that makes sure your building is protected. We handle pre-season inspections, spot problems early, and make repairs before they become emergencies. You get a roof that's ready for the rainy season without the stress of managing it yourself. Ready to prepare your roof for the rainy season? Contact us today.