Indoor Putting Greens: Basements, Garages and Simulator Rooms

An outdoor green in Ontario gets used from April to November. An indoor putting green gets used in January, which is why so many golfers here build one in a basement, a garage or alongside a home simulator. Indoors there's no excavation and no gravel, so it's simpler and usually cheaper per square foot than a backyard green. Getting it to roll like a real green still takes some planning.

How much space

Putting practice is mostly about putts of 3 to 15 feet, so length matters more than width. A long, narrow green along a basement wall is more useful than a square one. Common indoor greens run about 10 to 20 feet long and 4 to 10 feet wide. Leave room at the back of the stroke for your backswing, and keep a clear path around the green so nobody walks across it.

If the green shares a room with a simulator, plan the hitting area, the screen and the green together. Many people put a small green in front of the screen, or along one side of the bay.

The floor underneath

Indoors, the subfloor does what the gravel base does outside: it decides whether the ball rolls true. The floor needs to be flat and solid.

• Concrete basement or garage floors are solid but rarely perfectly flat, and can be cold and damp. A self-levelling compound fixes dips; a moisture barrier helps on below-grade slabs.
• Wood subfloors need to be stiff enough not to flex underfoot, or the ball wobbles as you walk around.
• Raised platforms, built from framing and plywood, are the usual way to add contour (break). Build the slopes into the platform, then lay the turf over it.

A thin foam pad between the floor and the turf evens out minor imperfections and makes the surface feel more like a real green. Too thick, and the ball rolls slow and soft.

Adding break

A dead-flat green teaches you to hit the ball straight and nothing else. A slight slope, built into a plywood platform or shaped with a pad, adds break so you can practise reading putts. Keep it gentle: a slope you can barely see creates a lot of break on a fast green. Some indoor systems use adjustable panels that let you change the break.

Choosing the turf

Use a dedicated putting turf, not landscape grass. Indoor putting turfs are usually non-infill or very light infill, made of a short, dense nylon or polyethylene fibre. They differ mostly in speed: how far a ball rolls for the same stroke. If you play a particular course, ask the supplier for a turf that matches its typical green speed. A fringe of slightly longer turf around the green is optional indoors but helps the green look finished.

Cups

Cups need depth. On a slab, a raised platform gives room for real cups; a thin green directly on concrete has to use shallow cups, cup-shaped targets, or a cut-out with a removable insert. Plan the cup positions before the platform is built.

Lighting and the room

Basements are often lit by a few ceiling fixtures that throw shadows across a green, which makes reading break harder. Even, bright lighting along the length of the green helps, as does a light-coloured wall at the far end so you can see the ball. In a garage, plan for the car: a roll-up green or one built on panels can be moved, while a fixed platform claims the space. Keep the green away from furnaces, water heaters and sump pits, which need access.

Common indoor green mistakes

• Building on an unlevelled slab, so putts drift for no visible reason.
• Too much slope on a short green, making it a lesson in frustration.
• Using landscape turf, which rolls slowly and unevenly.
• Forgetting cup depth until the turf is down.
• Leaving no room behind the ball for a full putting stroke.

Looking after it

Indoor greens need little care: vacuum or brush off dust, keep shoes clean, and brush the turf now and then to keep the roll consistent. Avoid rolling chairs or heavy items across it, which can leave lasting marks.

Combining a green with other uses

In a basement rec room, a green can share space with a play area or a home gym if it's built on removable panels. In a simulator room, putting turf in front of the screen lets the simulator's putting mode work on a real surface. If you might move house, a panel-built green can come with you; a glued-down one stays.

For a basement, check headroom over a raised platform too: a few inches of framing can matter under low ducts and beams.

What it costs

Without excavation and base, indoor greens usually cost less per square foot than outdoor ones, which Toronto-area installers publish at $20–$35 per sq ft installed. The cost guide for putting greens lists every figure for outdoor greens. Indoors, the price comes down to the turf, the pad, any platform framing and the size.

DIY or installer

A flat indoor green on a level floor is a reasonable DIY project: lay the pad, lay the turf, trim it, cut the cups. A contoured platform with built-in break, or a green integrated into a simulator room, is where an installer earns their fee. Send a request with the room dimensions and we'll pass it to one who builds putting greens.