PVC Siding: Vinyl vs. Cellular PVC and How to Install It
Updated · By the Roof to Footing editors
PVC siding is siding made from polyvinyl chloride. The term covers two different products: standard vinyl siding, the thin hollow panels on millions of American houses, and cellular PVC siding, solid foamed-PVC boards that look and cut like painted wood. Both won't rot, both need room to expand with temperature, and they differ a lot in thickness, price and how real they look.
Vinyl vs. cellular PVC
| Vinyl siding | Cellular PVC siding | |
|---|---|---|
| Form | Thin hollow panels, interlocking | Solid foamed boards, lap or shiplap profiles |
| Thickness | About 0.040 to 0.050 inch | Around 1/2 to 3/4 inch |
| Look | Panel seams and a molded grain | Close to painted wood; crisp edges |
| Cut and fasten | Snips or saw; nailed loosely through slots | Woodworking tools; nailed or screwed like wood |
| Impact | Can crack in cold | Tougher; dents less |
| Paint | Factory color | Factory finish or paintable with approved paints |
| Cost | Low | Higher, closer to fiber cement or wood |
Cellular PVC is best known as trim (corner boards, fascia, window casing), and many houses pair vinyl siding with PVC trim.
Expansion: the rule that matters most
PVC expands and contracts much more than wood. A long run of vinyl siding can change length by about a half inch between a cold winter morning and a hot summer afternoon. If it can't move, it buckles and waves. That's why the installation rules for vinyl are strict:
- Nail in the center of the slots, so the panel can slide both ways.
- Don't drive nails tight. Leave about 1/32 inch (roughly a dime's thickness) between the nail head and the panel.
- Leave gaps at the ends. Typically about 1/4 inch where panels meet trim or channels, and more (around 3/8 inch) when installing in cold weather, because the panel will grow later.
- Space nails according to the manufacturer, commonly every 16 inches.
- Don't face-nail or caulk panels tight to trim.
Cellular PVC boards are nailed more like wood, but they also need expansion room at butt joints, and dark colors absorb more heat, so some makers limit which colors you can paint them.
Pros
- No rot, no insect damage
- Low maintenance: wash with a garden hose and soft brush
- Wide range of colors and profiles, including shakes and board and batten
- Lightweight and fast to install (vinyl)
Cons
- Vinyl can crack from impacts in cold weather and melt from a grill or a reflective window nearby
- Combustible; check wildfire-zone rules
- Color is part of the material; vinyl can't be painted dark colors without special products
- Not as convincing up close as wood or fiber cement (vinyl)
Insulated vinyl
Some vinyl siding comes with foam bonded to the back. It stiffens the panel so it looks straighter and resists impact better, and it adds a small amount of insulation. It costs more than standard vinyl.
Soffit and trim
Vinyl and PVC soffit panels pair naturally with PVC siding. To size soffit material and venting, use our soffit calculator. For a shake look in vinyl, see shingle siding.