Carpet padding is the unsung part of any carpet installation. Most homeowners pick whatever the installer recommends without realizing that padding choice affects how the carpet feels underfoot, how long it lasts, and how well it insulates against noise and cold. The right pad depends on the carpet type, the subfloor, and how the room gets used.
Carpet sits on top of padding but is anchored to tack strips around the room's perimeter, not to the pad itself. This means the pad acts as a shock absorber for every footstep, extending the carpet's life by cushioning the backing against the hard subfloor. Without adequate padding, carpet fibers compress and mat out much faster, and seams wear through prematurely. A good pad also adds an R-value of 1 to 2, which is meaningful over a cold concrete slab in a basement or first-floor room above a crawlspace.
There are three broad categories of carpet pad sold at retail, each with different performance characteristics and price points.
Rebond foam, made from recycled foam scraps bonded together, is the most common residential padding. It's sold by density (pounds per cubic foot) and thickness. Look for at least 6-pound density for most rooms; 8-pound is better for high-traffic areas. Rebond is affordable, widely available, and works well under most cut-pile and loop-pile carpets. Avoid rebond under berber or level-loop carpet. The give in foam padding causes those styles to pill and snag over time.
Fiber pads are made from natural or synthetic fibers (jute, wool, or recycled textiles). They're denser and firmer than foam and are often recommended under berber and commercial-grade loop carpets because they provide support without excessive flex. Fiber pads also resist moisture better than foam and are a good choice in finished basements when a slight dampness risk exists. They cost more than rebond but last longer under heavy foot traffic.
Rubber pads come in waffle-textured and flat varieties. Flat rubber is denser and used in high-end residential and commercial installs where minimal compression matters. It's the most durable option but also the most expensive. Waffle rubber is softer and provides a plush feel similar to thick foam. Rubber pads resist moisture and don't compress permanently the way foam can, making them a good choice for stairs and entry areas.
Carpet pad thickness typically runs from 1/4 inch to 1/2 inch. The common advice to 'get the thickest pad possible' is wrong for many carpet types. Thick, soft pads under loop-pile or berber carpet cause the loops to flex and break down faster. Most carpet manufacturers publish a maximum pad thickness recommendation in their warranty documentation. Exceeding it can void the warranty. For plush and textured cut-pile carpets, 7/16-inch pad at 6-8 pound density is a solid all-around choice. For berber and commercial loops, a firm 3/8-inch pad works best.
Installing carpet over a concrete slab in a basement requires extra attention to moisture. Concrete is porous and can transmit ground moisture upward, even when it looks dry. Many pads marketed for basement use include a built-in moisture barrier on the bottom face. If yours does not, consider installing a sheet of 6-mil polyethylene vapor barrier between the slab and the pad, taped at the seams. Test the slab first by taping a 12x12-inch square of plastic sheeting to the floor with all edges sealed; leave it for 24 hours and check for condensation under the plastic. If moisture appears, address the source before installing any carpet.
Padding is sold by the square yard, like carpet. Measure each room's length and width in feet, multiply to get square footage, and divide by 9 to convert to square yards. Add 10% for waste from cuts and seams. For a room that is 12 feet by 15 feet: 180 square feet divided by 9 equals 20 square yards. Order 22 square yards to allow for waste. Padding comes in rolls that are typically 6 feet wide, so the installer will cut strips to fit the room. If you're buying pad separately from installation, confirm the roll width and calculate the linear footage you'll need.
Tack strips go in first, nailed around the room's perimeter about 2/3 of an inch from the wall. The pad then goes down in strips running perpendicular to the carpet seams and is stapled or glued (on concrete) to the subfloor. Pad seams should never align with carpet seams. Offset them by at least 6 inches. Butt pad edges together tightly and tape them with duct tape or seam tape; gaps in the pad create soft spots that are visible through the finished carpet. Trim the pad back 1/4 inch from the tack strip teeth so the carpet can hook cleanly onto the strips without riding over excess pad.
