From heat to moisture, many things can cause vinyl to bubble. Here's how to diagnose the problem and fix it for good.
Bubbles in Your Vinyl Siding? What Could Be Wrong (And How to Fix It)
Published on May 30, 2025
Vinyl siding can save a lot of hassles on a home, since it’s low-maintenance and never needs painting. But, it’s not foolproof. If your siding has started to bubble, it’s important to figure out the cause.
“Bubbles are like your home’s way of crying for help,” says contractor Chris Hock. “People think they can just push the bubbles back in or heat them with a hair dryer to flatten them out, but that’s like putting a band-aid on a broken bone. You’re not fixing the problem, you’re just hiding it temporarily.”
If your vinyl siding is bubbling, or you’re worried that it might start to, here’s what to know about the causes, plus how to fix it and prevent it from happening again down the road.
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Why Is My Vinyl Siding Bubbling?
Heat Exposure
Vinyl, which is made from PVC, can soften and warp under concentrated heat from reflected sunlight and hot objects. With bubbling siding, “the number one culprit I see is heat exposure,” says Hock. “Vinyl starts getting soft around 160 degrees, and I’ve seen barbecue grills, fire pits and even sunlight reflecting off Low-E windows turn beautiful siding into a melted mess.”
Trapped Moisture
Another main reason vinyl siding will bubble is moisture. “Moisture can sneak in behind the siding if the house wrap isn’t sealed well, or if there’s poor ventilation,” says construction specialist Ali Hassan. “That moisture expands when it heats up and causes bubbling.”
Other scenarios that can allow moisture to get behind your siding include clogged gutters, damaged flashing and leaky pipes.
Improper Installation
If vinyl siding is nailed too firmly, that can cause bubbling. That’s because not only does vinyl siding require space between the wall for proper ventilation, it especially needs room to expand and contract with temperature changes.
“Vinyl siding is designed to move,” says Hock. “It’s a floating system, not a rigid one. But I see contractors all the time nailing it down tight like they’re hanging drywall. That’s a recipe for disaster.”
Substrate Issues
Vinyl siding needs to be installed onto a surface that is in good condition. “I always tell my clients: the wall behind the wall matters most,” says Hock. “If you’re installing vinyl over warped sheathing or areas with moisture problems, you’re building trouble into your house.”
Other Factors
There are a few other reasons why vinyl siding can bubble, says restoration contractor Shannon Allen, including reactions with harsh chemicals and improper cleaning solutions. “Also, if a building settles or experiences shifts, it can cause the siding to buckle or bubble,” he says. “Termites or other insects can also chew through the sheathing beneath the siding, leading to warping or bubbling.”
Hail damage can also cause bubbled siding. And while manufacturing defects are rare, they can happen.
How To Fix Bubbled Vinyl Siding
Once your panels have bubbled, their integrity has been compromised. That means the only fix is to replace them.
Heat Exposure
If the source of heat was from the sun, consider swapping the damaged panels out with lighter colors. “Using lighter colors can reduce heat absorption,” says Hassan. “I once worked on a home where bubbling started near a south-facing wall with dark siding, so switching panels to a lighter shade helped stop the problem from coming back.”
Trapped Moisture
Again, you’ll have to replace the affected panels. “When the panels are pulled off, you can then check to see if there is moisture damage and what has caused it, then fix the root of the problem so you won’t face the same problem in the future,” says construction specialist Drew Mansur.
Improper Installation
If bubbling vinyl is the result of panels being nailed too tightly, the good news is you probably don’t have to buy new ones. Instead, you can just reinstall the panels using the proper nailing technique, which leaves enough space for movement.
How To Prevent Vinyl Siding Bubbling
In general, to prevent bubbling siding, never install it in weather below 40 degrees, or the material can become brittle, plus problematic once it heats up. “Remember, vinyl needs room to breathe,” says Hock. “Think of it like hanging curtains, not building a fortress.”
Also, it’s important to follow manufacturer care instructions after the install, which usually include washing it regularly with a garden hose and soft-bristle brushes, says contractor Austin Lako. “Most manufacturers discourage the use of pressure washers and harsh cleaning chemicals, which can void the warranty and lead to damages that could increase the likelihood of bubbling,” he says. “One of the most common misconceptions I hear is that vinyl siding is maintenance-free.”
Heat Exposure
Specifically for heat exposure, never grill within three to five feet of vinyl siding, says Lako, and if reflected sunlight is hitting your siding, install window screens or awnings, or strategically place landscaping to mitigate the issue.
“South-facing walls are most at risk,” says contractor Josh Riutta. Also, “Watch for warping near patios or neighbors’ windows.”
Hock also recommends using an infrared thermometer to check the temperature of any siding in question. “Homeowners are always shocked when I show them their siding is hitting 140-plus degrees from reflected light,” he says. “If any area consistently hits over 140 degrees, you’re in the danger zone.”
Trapped Moisture
To prevent vinyl bubbling from moisture, always install quality house wrap and insure everything is dry before installation, says Riutta. Also, check that gutters and flashing aren’t channeling water behind the siding.
“Prevention starts with careful installation and making sure there’s enough airflow behind the siding to keep things dry,” says Hassan. “Avoid rushing installation or cutting corners on moisture barriers and ventilation, and those bubbles won’t bother you much.”
Improper Installation
When installing vinyl siding, check manufacturer’s recommendations for proper spacing between the nail head and the wall surface, which typically ranges from 1/32″ to 1/8″.
“Use a nailing flange and center each nail in the slot,” says Lako. “A good rule of thumb: if the siding can’t move slightly side to side when tapped, it’s nailed too tight.”
About the Experts
- Chris Hock is founder of Earth Saving Solutions, a full-service general contractor serving the Denver Metro area since 2008. His specialties include construction, remodeling and restoration services.
- Austin Lako is owner of Lake Effect Exteriors in southeast Michigan, which specializes in exterior remodeling, including roofing, siding and decks.
- Josh Riutta is owner of Mikku and Sons Roofing. He has more than 25 years of experience in the roofing industry and as a general contractor.
- Ali Hassan is a construction and roofing specialist at Rabbit Roofing in Florida.
- Shannon Allen is Director of Commercial Operations at Rainbow Restoration, a Neighborly company.
- Drew Mansur is co-founder of TileCloud and Yabby, two companies in the renovation space, and holds a degree in construction management from the University of UNSW.
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