Sand and Polish or Replace? 7 Signs Your Old Floorboards Can Be Saved

I've been sanding, repairing and laying timber floors around Sydney since 2006, and a lot of calls start with "I think we need new floors." Often they don't. A floor that looks grey, scratched and tired usually has a finish problem, not a timber problem, and the boards underneath can have decades left in them.

But not always. Some floors have been sanded too many times. Some have damage that goes deeper than a sander can reach. And some are hiding a problem under the house that will ruin a fresh finish within a year. These are the seven checks I make before recommending a sand and polish, a repair or new boards. You can do most of them yourself this weekend. The ones you can't do yourself are why a site assessment exists.

Why most "worn out" floors aren't

A timber floor has two parts: the timber and the coating on top. Foot traffic, grit, chair legs and sunlight wear the coating first. Once it's thin, the floor goes grey and patchy in the hallway and in front of the kitchen bench, and the bare timber starts soaking up spills.

Sanding removes the old coating and a thin layer of the timber surface, exposing fresh timber underneath. New coats go on top. Solid hardwood floorboards can usually be sanded more than once over the life of the floor.

So the question isn't "does my floor look bad?" It's "is there enough sound timber left to sand, and is anything underneath going to undo the work?"

A floor that looks worn out is usually wearing out its coating, not its timber.

1. Is it solid timber at all?

Sanding only makes sense if there's real timber to sand. Before anything else, work out what you've got.

• Solid hardwood floorboards are timber all the way through. They're common in older Sydney houses, usually laid over joists, and they're the best candidates for sanding.
• Engineered timber has a real timber top layer bonded to a core. Whether it can be sanded depends on how thick that top layer is. Some can be sanded once or twice. Thin ones can't be sanded at all.
• Laminate and hybrid floors have a printed image under a wear layer. They can't be sanded. If they're damaged, the damaged planks get replaced.

2. How much timber is left above the tongue?

For solid floorboards, this is the check that decides everything. Tongue-and-groove boards lock together with a tongue on one edge. Sanding can only go so deep before it gets close to the tongue and groove, and then the board loses strength and starts breaking up along the joints.

A floor that's been sanded several times, or sanded hard to flatten cupped boards, may have less left than you'd expect. Warning signs:

• Nail heads sitting at or just below the surface, or nail holes that look shallow.
• Joints opening up into the groove, or splintering along the board edges.
• Boards that look thin where you can see a cut edge.

You can't judge this from photos. On site, I check at vents, thresholds and anywhere a board edge is exposed, and I look at how the nails sit. Top-nailed floors need the nails punched below the surface before sanding, and that tells you a lot about how much depth is left.

3. Are the stains on the surface or in the timber?

Most marks sand out: scuffs, scratches through the coating, light water rings, grey traffic paths and old yellowed finish.

These often don't:

• Black or dark grey stains, especially rings or blotches. Water and pet urine react with the tannins in many hardwoods and can stain deep into the board.
• Deep dents and gouges from dropped objects or heavy furniture. Light dents can come out. Deep ones may not.
• Paint, glue or bitumen that has soaked into the grain during past renovations.

A few stained boards aren't a reason to replace the whole floor. They can usually be cut out and replaced with matching timber, then the whole floor sanded and coated together. Our floorboard replacement service explains how that works.

4. Does the floor feel solid underfoot?

Walk the whole floor slowly in socks. You're feeling for:

• Spots that bounce, sag or feel soft.
• Boards that move or click under your weight.
• New squeaks in an area that used to be quiet.

Some movement and squeaking is normal in older floors, and it can usually be fixed by re-fixing the boards to the joists. Soft or spongy spots are different. They can mean rot, termite damage or a problem with the framing underneath, and that has to be found and fixed before any sanding. Sanding over a soft spot just gives you a shiny soft spot.

5. Is there a moisture problem underneath?

Look across the floor at a low angle near a window. If the boards look dished, with the edges higher than the middle, that's cupping. It usually means moisture is coming from below. Sand a cupped floor flat while it's still damp, and the boards can crown as they dry out, leaving each board higher in the middle than at the edges.

In Sydney homes, the usual causes are blocked subfloor vents, poor drainage, leaking pipes under the house and damp crawl spaces. These need fixing first, then the floor needs time to settle. If you want to go deeper on this one, I've written a full guide to floorboard gaps and cupping.

6. Has it been patched or mixed over the years?

Older Sydney houses have often been renovated several times. Once the carpet comes up, it's common to find:

• A section of different timber where a wall came out or a fireplace was filled in.
• Particleboard or plywood patches in old kitchens and bathrooms.
• Boards of a different width or direction in an extension.

None of that rules out a sand and polish, but it does change the plan. Mismatched sections can sometimes be replaced with boards that match the rest of the room. Particleboard needs replacing with timber if it's going to be sanded and coated. If you've just pulled up carpet, our guide to replacing carpet with timber covers both paths.

7. Does the look you want need new boards?

Sometimes a floor is fine to sand, but the look you want isn't possible with those boards. A sand and polish can change the colour with a stain or a different coating. It can't change the species, the board width or the pattern. If you've got your heart set on wide European Oak boards or a herringbone floor, that's new flooring. See our herringbone and chevron installation or supply and install service.

It's also worth thinking ten years ahead. A floor near the end of its sanding life might take one more sand and look great, and then have nowhere left to go.

Sand and polish, repair or replace: a quick guide

What a sand and polish involves

Once a floor is ready, the job runs in a set order:

1. Furniture out, loose boards re-fixed and nails punched below the surface.
2. Any replacement boards fitted.
3. Sanding in stages with progressively finer paper, plus edge sanding along the walls.
4. Gaps and nail holes filled where suitable.
5. A final fine sand and a thorough vacuum.
6. A stain if you've chosen one, then several coats of the finish.

We use vacuum-assisted sanding equipment to cut down dust at the source, though no sanding job is completely dust-free. How long you'll need to stay off the floor depends on the coating, the number of coats and the weather, so I'll give you a plan for your floor rather than a generic number. Our floor sanding and polishing page covers recoats, finishes and what to plan around.

Do it yourself, or call someone in?

You can do the first round of checks yourself. Work out what the floor is made of, walk it, look for stains and cupping, and lift some carpet. That alone will tell you a lot.

Hiring a drum sander for the weekend is tempting. The catch is that it's very easy to take off too much timber in one spot, leave dips and ripple marks, or sand through a floor that didn't have much left. Unlike paint, you can't put timber back.

If you'd rather know exactly where your floor stands before deciding, that's what the free on-site quote is for. If a recoat is all it needs, I'll tell you. If it's not worth sanding, I'll tell you that too.