Carpet Installation for Bedrooms, Stairs & Basements

Underlay isn't only there for comfort. It takes much of the pounding that would otherwise break down the carpet's backing. A thin, cheap pad lets a good carpet wear out from underneath.

Thicker isn't automatically better, though. Carpet makers usually set a maximum thickness and a minimum firmness for the pad under their product, and loop-style carpets generally need something thinner and firmer than a plush cut pile. On stairs, a thick, soft pad makes the front edge of each step feel mushy underfoot, which is the last thing you want where people trip. The goal is the right underlay for that carpet in that room, not the thickest roll available.

Then there's the stretch. Around the edges of the room, carpet is held by tack strip: thin wood strips with angled pins that grip the backing. To stay flat, the carpet has to be pulled tight across the whole room before it's hooked on. A power stretcher does this by bracing against the far wall and pulling with steady, even tension.

The shortcut is to do the whole room with a knee kicker, a small tool you bump with your knee. It's the right tool for closets, stair treads and hooking edges, but it can't put enough tension across a bedroom. Carpet laid that way tends to relax into ripples within a few years, and the ripples wear faster because each raised ridge takes the scuffing. You can't vacuum them out. The fix is a re-stretch, which means emptying the room again.

Bedrooms are the easy case. Traffic is light, so a softer carpet does fine, and polyester or a soft nylon both work. The main decisions are colour, feel and an underlay that suits the carpet.

Stairs take more wear than any other carpet in the house. Every step gets hit in the same spot, and the front edge (the nose) gets bent and scuffed on every trip. That's where you want nylon and a firm pad. There are two common ways to carpet a stair. A waterfall install runs the carpet over the nose and straight down to the next step. A capped, or Hollywood, install wraps the carpet tightly around the nose and tucks it underneath, which looks more tailored and takes longer to fit. Either way, the pile should run down the stairs so every step wears and looks the same.

Basements need one check first. Concrete slabs give off moisture from the ground, and carpet over a damp slab can turn musty or grow mould underneath where nobody sees it. A simple test: tape a square of clear plastic, roughly 45 cm across, to the bare concrete, seal all four edges, and look under it after a day. Fog on the underside of the plastic, or a darker patch of concrete, means moisture is coming through. It's a rough check, not a measurement: a dry result on one day doesn't rule out damp in a wetter season.

A dry slab can take carpet with a suitable underlay. Some pads have a thin film on top that stops spills and pet accidents soaking into the pad, but no underlay fixes a damp floor. If the basement has ever had water on the floor, choose something that survives getting wet. Luxury vinyl plank is waterproof and a better fit for that room.