Solid vs Engineered Hardwood: Which Can Be Sanded?
Solid hardwood survives 4–6 sandings. Engineered survives 1–2 if at all. How to tell what is under your feet before you book a contractor.
The single most expensive misunderstanding in residential flooring: assuming any wood floor can be sanded and refinished. It can't. Solid hardwood survives 4–6 sandings over its lifetime. Engineered hardwood survives 1–2 if you're careful, and many engineered floors can't be sanded at all. Here's how to tell what's under your feet before you book a contractor.
The fundamental difference
Solid hardwood is a single piece of wood, typically ¾" (19 mm) thick, milled with tongue-and-groove edges and nailed to a wood subfloor. The full thickness is the same species — sand off the top millimetre and the next millimetre below is identical wood.
Engineered hardwood is a sandwich. The top layer (the "wear layer") is real hardwood — usually 1–4 mm thick — bonded to a plywood or HDF core. The wear layer is what gets sanded. Once you grind through it, you hit plywood, and the floor is finished.
How to tell what you have
Without lifting a board, three checks usually settle it:
- Look at a heating register or stair nose. Pull the metal grate. The exposed plank edge will show either a solid grain pattern top-to-bottom (solid) or a thin top stripe over light-coloured plywood (engineered).
- Tap test. Solid hardwood thuds with a resonant low note when you knock on it. Engineered sounds hollower and higher because of the layered core.
- Floor height vs the threshold. Solid ¾" floors usually sit on top of a ¾" plywood subfloor — total height ~38 mm above the joist. Engineered ⅜" or ½" floors with a plywood subfloor land lower. If a doorway threshold is unusually flush, it's likely engineered.
If you're still unsure, we measure with a spring-loaded depth gauge on a hidden spot during the on-site quote. Takes 30 seconds.
Engineered wear-layer thickness — the actual rule
| Wear layer | Sanding lifetime |
|---|---|
| 1 mm | Zero. Don't try. Buff and re-coat only. |
| 2 mm | One light sanding, screen-and-recoat after that. |
| 3 mm | One full sanding plus one screen. |
| 4 mm+ | Two sandings comfortably. |
| 6 mm+ (rare, premium engineered) | Treat like solid — 3–4 sandings. |
Why this matters before you call
A contractor who agrees to sand 2 mm engineered without checking is going to grind through it on the first pass, expose the plywood, and either (a) confess and stop, or (b) keep going and ruin the floor. The right move on thin engineered is screen-and-recoat — a light buff with a fine screen, no removal of the wear layer, followed by a fresh coat of polyurethane. It refreshes the look without burning thickness.
What to ask a contractor
- "Will you measure the wear layer before quoting?"
- "If it's too thin to sand, what's the alternative and what does it cost?"
- "Have you sanded engineered before, and do you have references?"
If you're not sure what you have, we'll come measure for free. Request an on-site assessment.
