What is vinyl siding?
Updated August 2026
Vinyl siding is interlocking PVC panels that hang loosely on a home's exterior walls as its outer weather layer, and it is the most common cladding on US houses because it never needs paint. Panels run roughly 0.040 to 0.046 inch thick, snap into the course below them, and get nailed through slotted holes along the top. Those slots matter more than anything else in the install: a 12-foot panel grows and shrinks as much as 1/2 inch between a January morning and a July afternoon.
Where it is
It is the wall covering itself, so identifying it takes a tap and a close look. Vinyl sounds hollow, flexes under thumb pressure, and shows a lip at the bottom of each course where it locks into the panel below. Follow a wall to a corner or a window and you will see J-channel, the trim that panel ends slide into without being fastened. Behind the panels sit housewrap and sheathing, and the housewrap, not the vinyl, is the actual water barrier. Vinyl works as a rain screen: water gets behind it by design and drains out through the weep holes punched in the bottom of every panel.
What it does
Siding sheds wind-driven rain and takes the sun so the structure does not. What vinyl asks in return is room to move. Nail it tight and a panel has nowhere to expand, so it buckles into visible waves on the first hot afternoon. Heat and cold are its other weaknesses. A grill or dryer vent parked too close can soften a panel, and low-angle sun bouncing off a neighbor's low-E window has warped whole walls in a single summer. Below about 40 degrees the material turns brittle, so a stray baseball or a ladder foot cracks it rather than dents it. Color fades over 15 to 20 years, unevenly on the south and west elevations. Expect 20 to 40 years total.
Maintenance
Wash it once a year in spring with a garden hose, a soft brush, and a bucket of oxygen bleach. North-facing and shaded walls grow the green-black mildew film first and usually need a second pass. Budget 2 to 4 hours on a typical two-story house, or $250 to $600 for a soft-wash contractor. While you are down at ground level, walk the perimeter: push on panels to find any that have come unlocked, look for cracks radiating from nail heads, and confirm every dryer and bath vent hood still swings free. The rest of the yearly siding routine adds about 30 minutes.
What it costs to replace
A replacement vinyl siding runs about $8–14 per square foot to reside a house, or $2–7 per square foot for spot panel repairs.
OnOtto's photo scan identifies parts like this in your home and builds the maintenance schedule for you. See how the scan works.
Frequently asked questions
Can you paint vinyl siding?
Yes, under two rules. Use a vinyl-safe acrylic or urethane exterior paint, and never go darker than the original color: dark pigment absorbs more heat, and panels engineered for a light shade will warp. Prep means a full wash and a dry surface. Expect $1.50 to $4 per square foot for a pro, a repaint every 7 to 10 years afterward, and no more maintenance-free siding. Past about 25 years, residing usually makes better financial sense than painting.
Why is my vinyl siding wavy?
Three causes, in order of likelihood. Nails driven tight against the nailing hem instead of leaving roughly 1/32 inch of play, so panels cannot slide as they expand. Siding installed over uneven foam or old wood siding that telegraphs through. Or heat, from a grill, a reflective window, or a dark repaint. Waviness that appears on hot days and relaxes overnight is expansion. Permanent waves mean the panels come off and go back on, roughly $2 to $5 per square foot.
Can you pressure wash vinyl siding?
You can, and a pressure washer is also the fastest way to drive water behind the panels into the wall. If you use one, stay under 1,500 psi, fit a wide 40-degree tip, hold the wand level or angled slightly down, and stay 2 feet back. Never spray upward under a course. A garden hose with a siding brush, or a contractor soft-wash at 100 to 500 psi with detergent, kills mildew just as well without soaking the sheathing.
How hard is it to replace one cracked panel?
Easier than it looks. A $6 zip tool unhooks the panel above, you pull the nails, slide the damaged piece out, and lock a new one in. The panel itself is $3 to $8. Color is the hard part: 15-year-old siding has faded, current stock has not, and plenty of profiles are discontinued. Check the garage and the crawl space for leftovers first. If you must buy new, pull a patch panel off a hidden wall and put the fresh one there.