Sanding and Smoothing Benches for Comfort

Why Comfortable Benches Matter

A sauna is meant to help you relax and unwind. The Cleveland Clinic notes that saunas may reduce stress and improve heart health, and a comfortable bench makes it easier to stay seated and enjoy the session. If the wood is rough or has splinters, you are more likely to shift around or cut the session short.

MrSteam's design basics describe creating a spa-like sanctuary at home, which includes comfortable seating. Even if you already own a sauna, sanding the benches can make the experience more pleasant, especially if you plan to sit for the recommended 10 to 20 minutes. A smooth surface also helps you stay longer and get the full relaxation benefit.

When shopping for a new sauna, look for benches that are already sanded and have rounded edges. Many manufacturers shape the wood before assembly, which saves you the effort. Check the product photos or ask the seller if this is a feature. For help comparing models, see our guide to the best 3-person saunas.

Light Sanding: When and Why

Over time, sauna benches can develop rough patches, especially in areas where you sit or where your feet rub. This is normal for unfinished wood. Light sanding removes the top layer and restores a smooth surface without changing the wood's character.

You do not need to sand aggressively. A light pass with a fine-grit sandpaper or a sanding sponge is enough. Focus on the top surface and the edges that you touch most. For most saunas, a quick sanding once a year keeps benches comfortable. If you notice splinters, sand them out before your next session, as waiting can allow the wood to crack further.

Before you begin, check for any loose slats or screws and tighten them. Sanding on a stable surface is easier and safer. If your benches are removable, you can work on them outside or on a workbench. If you have a permanent bench, you can sand in place but cover the floor to catch sawdust.

The wood species affects how often you need to sand. Softer woods like pine and spruce may show wear more quickly than harder woods like cedar or aspen. For more on wood selection, read our article on which sauna wood is best.

Rounded Edges for Comfort and Safety

Sharp 90-degree edges on benches can dig into your legs or back, especially when you sit for extended periods. Rounding the edges with a rasp or sandpaper makes the bench more comfortable and reduces the chance of splinters and snags.

Use a sanding block or a small hand rasp to create a gentle curve. You do not need a large radius; a small chamfer is usually enough. Test the edge with your hand to ensure it feels smooth. If the bench has a sharp corner, round that too, as corners are common points for splinters.

If you are buying a new sauna, look for models where the benches come with pre-rounded edges. Many manufacturers shape the wood before assembly, which saves you the effort. Check the product photos or ask the seller if this is a feature. For a list of models with comfortable seating, see our best 2-person sauna gear or best 4-person sauna gear.

Choosing the Right Grit: What to Use and What to Avoid

For light sanding, a fine-grit sandpaper is best. A coarse grit can leave deep scratches that are hard to remove and may weaken the wood. It is only useful for heavy re-profiling, which is rarely needed on a bench.

Start with a medium-grit sandpaper if you need to smooth a rough area, then move to a finer grit for a silky finish. Always sand with the grain of the wood to avoid visible marks. Avoid ultra-fine grits that can make the surface too slick and slippery when wet.

You can use a sanding sponge or a block to apply even pressure and avoid gouging the wood. For curved areas, wrap sandpaper around a small block or use a flexible sanding pad. A sanding sponge is especially useful for reaching between slats.

If you are re-sanding the entire bench, take care not to remove too much material. The bench thickness matters for structural support. For more on bench durability, see our article on sauna bench weight capacity.

What Finishes to Avoid on Sauna Benches

Never apply varnish, polyurethane, lacquer, or paint to sauna benches. These finishes can trap heat and release chemicals when the room gets hot. They also become sticky and uncomfortable with sweat and humidity. The Finnleo FAQ advises that wood choice is largely a matter of preference, but finishes are not mentioned as a recommended option.

If you want to protect the wood, consider using a natural oil like mineral oil or paraffin oil, which some sauna owners prefer. However, many traditional saunas use unfinished wood benches because they dry quickly and feel comfortable at high temperatures. Always check the manufacturer's recommendations for your specific model.

Some woods, like cedar, are naturally resistant to moisture and do not need any finish. If you are unsure about your sauna's wood, consult the owner's manual or a local wood specialist. For more on choosing the right wood, see our guide to sauna wood selection.

Another option is to use a sauna bench cushion or a towel to protect the wood and add comfort. But these do not replace sanding. For cushion options, see our article on bench cushions or towels.

Maintenance Tips Between Sandings

Between sanding sessions, keep the benches clean and dry. Wipe them with a damp cloth after each use if allowed, but avoid letting water sit on the wood. Good ventilation helps the wood dry and reduces the chance of splinters.

Inspect the bench regularly for rough spots or pressure marks. If you notice a splinter starting, sand it lightly with fine-grit before it becomes a problem. A quick touch-up is much easier than a full sanding.

If you have a removable bench, you can store it in a dry place between uses, especially if you do not use the sauna frequently. For more on bench care, see our article on cleaning the floor or routine after each session.

What to pick for your use

Questions

How often should I sand my sauna benches?

Once a year is a good guideline, or whenever you notice roughness or splinters. Light sanding with a fine grit keeps the surface smooth without wearing down the wood. If you use the sauna very frequently, you may need to sand more often.

Can I use varnish on sauna benches?

No. Varnish, polyurethane, and similar finishes trap heat and can release fumes at high temperatures. They also become sticky with humidity. Stick to unfinished wood or natural oils like mineral oil if you need protection.

What is the best way to round bench edges?

Use a rasp or a sanding block to gently curve the edge. Sand with the grain and check with your hand for smoothness. A small chamfer is usually sufficient to prevent splinters and pressure marks.

Do I need to sand new sauna benches?

Usually not, but inspect them before first use. Some manufacturers leave sharp edges or tool marks. A quick light sanding can improve comfort without affecting the wood's integrity. If the benches are pre-sanded, you can skip this step.

What type of sandpaper should I use?

For light sanding, use a fine grit (around 120 to 150) for smoothing. If you need to take down a rough area, start with a medium grit (80 to 100) and finish with a fine grit. Always sand with the grain to avoid scratches.