A floor's installation method changes more than the workday — it changes how the floor feels underfoot, how much noise it makes, how well it tolerates a damp concrete slab, and how easy it is to fix later. There are three main ways a floor attaches to (or floats over) the subfloor: floating (interlocking planks riding, unattached, over an underlayment), glue-down (bonded across the full surface with adhesive), and nail-down or staple-down (mechanically fastened into a wood subfloor). A fourth, less common option, loose-lay, held by weight and friction, sits alongside them. Which method you get is usually decided by the flooring product and the subfloor underneath it, not by preference alone — a given plank is typically engineered for only one or two of these methods, and a bare concrete slab rules some of them out entirely. This guide walks through how each method works, what it suits, its honest pros and cons, subfloor prep, and expansion gaps and acclimation — plus how tile's thinset-mortar method relates but differs.
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Floating
In a floating installation, planks lock to each other — usually with a click-lock tongue-and-groove joint — but are never fastened to the subfloor itself. The whole assembled floor rides on a thin underlayment layer, held in place mainly by its own weight and the perimeter trim, with an expansion gap left around the room's edges. It's the method behind most LVP/LVT and virtually all laminate, plus many engineered hardwood products.
Pros: the most DIY-friendly of the three methods — no adhesive cure time or nail gun, and reasonably forgiving of minor subfloor imperfections (within the manufacturer's flatness limits); a single damaged board can often be popped up and swapped without redoing the room; it goes over a wide range of substrates, including concrete, without needing a wood subfloor layer.
Cons: without a good-quality pad, a floating floor can feel or sound slightly hollow underfoot compared with a glued or nailed floor; large open spans need transition strips to break up expansion runs; and because nothing is fastened down, a truly uneven subfloor telegraphs through more noticeably than it would under a glued installation.
See our full luxury vinyl, laminate, and engineered hardwood guides for how floating fits into each material.
Glue-down
A glue-down installation bonds each plank or tile directly to the subfloor with a full spread of adhesive, rather than letting the pieces float or lock to each other alone. It's common for engineered hardwood (especially over concrete or under wide planks, where extra stability matters) and for LVT in commercial or large-format residential settings.
Pros: a fully bonded floor feels and sounds solid and quiet underfoot; it's dimensionally stable, which suits large open areas and helps control movement under wide-plank product; and it performs well directly over concrete, where a fastened method isn't an option.
Cons: it's labor-intensive — the subfloor has to be genuinely flat, clean, and dry before adhesive goes down, with essentially no room for error in coverage; and once cured, a glue-down floor is difficult to remove or repair without damaging boards or the subfloor beneath.
Tile is a related but separate case: it's bonded with thinset mortar rather than a flooring adhesive, over a proper substrate or backer board — see which method for which material below, and our tile flooring guide for the full method.
Nail-down & staple-down
Nail-down and staple-down installations mechanically fasten each board into a wood subfloor — plywood or OSB over joists — using flooring cleats, nails, or staples driven at an angle through the board's tongue, a method also called blind-nailing. It's the traditional method for solid hardwood, and it's also used on thicker engineered hardwood built to accept fasteners.
Pros: proven over generations, it produces a solid, traditional wood floor with no click-lock joints to fail and no adhesive to fully cure.
Cons: it needs a sound wood subfloor — it isn't done by nailing directly into a concrete slab, so a below-grade or slab-on-grade room needs a code-compliant plywood subfloor layer added first before nail-down is even possible, and it takes tools (a pneumatic flooring nailer/stapler) and technique most homeowners don't already have.
Loose-lay
Loose-lay vinyl is a smaller category worth naming on its own: heavier vinyl planks or tiles that stay in place through their own weight and friction against a clean, flat subfloor, sometimes with adhesive applied only around the room's perimeter — not a full-spread bond, and no interlocking joints between pieces. It's easy to install and individual pieces are easy to lift and swap, but it depends on a genuinely flat, clean subfloor to stay put and hide seams well.
Which method for which material & subfloor
| Material | Common installation method(s) | Notes |
|---|---|---|
| LVP/LVT (rigid core: SPC/WPC) | Floating (click-lock) is by far the most common; some large-format or commercial LVT is glue-down | Works over concrete or a wood subfloor; flatness still matters for a rigid core. See our luxury vinyl guide. |
| Laminate | Floating (click-lock) only | Never glued or nailed — always rides on an underlayment. See our laminate guide. |
| Engineered hardwood | Floating, glue-down, or nail/staple-down — varies by product | The manufacturer specifies which methods a given plank supports; thinner-veneer product is often floating-only. See our engineered hardwood guide. |
| Solid hardwood | Nail-down (traditional) | Needs a wood subfloor; not floated or glued in standard practice, and not installed directly over concrete. |
| Sheet vinyl / VCT | Full-spread glue-down | A continuous adhesive bond across the whole sheet or tile — not a click system. |
| Loose-lay vinyl | Loose-lay (weight + friction, sometimes perimeter adhesive) | Its own category — not floating (no interlocking joint) and not a full-spread glue-down. |
| Ceramic / porcelain tile | Thinset mortar — its own installation method | Requires a proper substrate or backer board, set per TCNA-defined methods. See our tile flooring guide. |
Subfloor type also gates what's possible. A concrete slab favors floating or glue-down flooring; nail-down needs a wood subfloor, so on a slab that means adding a code-compliant plywood layer first, not nailing into the concrete directly. A wood subfloor (plywood or OSB over joists) supports all three methods, which is why solid hardwood — nail-down only — is essentially restricted to on- or above-grade rooms with a wood subfloor. See our best flooring for basements guide for concrete and below-grade specifics.
Subfloor & prep by method
Every method depends on the subfloor being ready, but "ready" means something different for each one:
- Floating: needs a reasonably flat, clean, dry surface and a compatible underlayment; it tolerates minor imperfections better than glue-down, but manufacturers still publish a maximum flatness deviation.
- Glue-down: the least forgiving of the three. ASTM F710, the standard practice for preparing concrete floors to receive resilient flooring, calls for the slab to be permanently dry, clean, and structurally sound, with flatness held to roughly 3/16 inch of variation over 10 feet, plus moisture and alkalinity (pH) testing before adhesive is applied — and, on an on- or below-grade slab, a moisture vapor retarder beneath it.
- Nail-down: the subfloor must be sound structural wood — plywood or OSB per residential building code, over joists — dry, flat, and itself properly fastened; nailing is not done directly into concrete.
See the subfloor glossary entry for what the term covers, and our best flooring for basements guide for concrete-specific moisture testing and vapor-barrier guidance.
Expansion gaps & acclimation
Floating floors, and any solid or engineered wood floor regardless of method, need room to move, because wood- and fiber-based materials expand and contract with humidity year-round.
- Expansion gap: a deliberate gap left at the room's perimeter and around fixed obstructions, later hidden under baseboard, quarter round, or a transition strip, so the floor can expand without buckling. The exact size is set by the manufacturer — NWFA guidance commonly cites roughly 3/4 inch as a rule-of-thumb starting point for solid wood, but always confirm the number for your product.
- Acclimation: letting flooring sit in the room where it will be installed — enclosed and climate-controlled — until it reaches that room's normal temperature and humidity. NWFA guidance generally calls for holding the room around 60–80°F and 30–50% relative humidity for at least 48 hours before installation, with the flooring's moisture content brought within a few percentage points of the subfloor's (figures vary by product and species — check the manufacturer's instructions). Skipping acclimation is a common, avoidable cause of gapping, cupping, or buckling that shows up weeks after a job that looked fine on day one.
DIY difficulty by method
- Floating — easiest. Click-lock joints, basic tools (tape measure, spacers, tapping block, a saw), and a damaged board can be replaced without redoing the room.
- Loose-lay — similarly easy. No locking mechanism to learn; cut pieces to fit and set them in place on a flat, clean subfloor.
- Glue-down — harder. Trowel technique, adhesive working time, and coverage all affect the outcome, and mistakes are difficult to hide or undo once the adhesive sets.
- Nail-down — hardest of these three for most DIYers. Requires a pneumatic flooring nailer/stapler, careful layout, and blind-nailing technique; the tool and material investment alone lead many people to hire it out.
- Tile (thinset) — its own skill set, commonly hired out: layout, mortar mixing and coverage, cutting, and grouting. See our tile flooring guide.
Myths & mistakes
- Myth: "Glue-down is always more durable than floating." Durability comes mainly from the wear layer, core, and finish — not the attachment method. A quality rigid-core floating floor can outlast a poorly prepped glue-down job.
- Myth: "You can nail down any floor." Nail-down requires a product engineered for it (thickness, tongue-and-groove profile) and a wood subfloor. Most vinyl and laminate are floating-only and aren't rated for fasteners.
- Myth: "Floating floors are cheap or inferior." Floating is an attachment method, not a quality tier — many premium rigid-core LVP and engineered hardwood floors are specifically designed to float.
- Myth: "Underlayment and the subfloor are the same thing." The subfloor is the structural layer underneath everything (plywood, OSB, or concrete); underlayment is a thin cushioning/sound/moisture layer added under a floating floor.
- Myth: "Engineered wood is more stable, so it doesn't need acclimation or an expansion gap." More stable isn't immune — engineered hardwood is still real wood at the surface and needs both, the same as solid wood, with different manufacturer-set numbers.
Frequently asked questions
What's the actual difference between floating, glue-down, and nail-down flooring?
How the plank connects to what's underneath it. Floating planks lock to each other and ride, unattached, over an underlayment. Glue-down planks or tiles bond across their full surface to the subfloor. Nail-down or staple-down boards are mechanically fastened into a wood subfloor. The method changes how the floor feels, sounds, and can be repaired.
Can I install a floating floor myself?
For most people, yes — floating (click-lock) is the most DIY-friendly method: no adhesive cure time, no nail gun, and a damaged board can usually be replaced without redoing the room. Still follow the manufacturer's underlayment, expansion-gap, and acclimation instructions closely; those are the steps DIYers most often skip.
Can solid hardwood be installed over a concrete slab?
Not by nailing directly into concrete — nail-down requires a wood subfloor. Solid hardwood over a slab generally needs a code-compliant plywood layer added first, and it's still not the go-to choice below grade. Engineered hardwood, which can float or glue down, is the more common wood option over concrete or below grade. See our best flooring for basements guide.
Is a glue-down floor quieter than a floating floor?
Generally, yes — a full-spread adhesive bond tends to feel and sound more solid underfoot than an unattached floating floor, which can sound hollow over a thin or poor-quality pad. A good-quality underlayment narrows that gap but doesn't fully erase it.
What's the difference between loose-lay vinyl and floating click-lock vinyl?
Loose-lay pieces aren't attached to each other or the subfloor — they stay put through weight and friction, sometimes with adhesive only around the room's perimeter. Floating click-lock planks interlock with each other via a tongue-and-groove joint, which holds the field together more positively than loose-lay's friction fit.
Is setting tile in thinset mortar one of these three methods?
No — tile is its own installation system, set in cement-based thinset mortar over a proper substrate or backer board, following methods defined by the Tile Council of North America (TCNA). It isn't floated, glued as a full-spread plank adhesive, or nailed. See our tile flooring guide for details.
Sources
This guide describes standard practice as defined by the bodies below; we are not affiliated with any of them.
- NWFA — National Wood Flooring Association: wood flooring installation guidelines, including acclimation and expansion-gap guidance for solid and engineered wood.
- TCNA — Tile Council of North America: the Handbook for Ceramic, Glass, and Stone Tile Installation, which defines standard thinset-mortar tile installation methods.
- ASTM International — ASTM F710, Standard Practice for Preparing Concrete Floors to Receive Resilient Flooring, covering concrete subfloor flatness, moisture, and pH-testing requirements.
Keep going: see the full material guides for luxury vinyl, laminate, engineered hardwood, and tile; check below-grade specifics in best flooring for basements; or start from room needs with the how-to-choose framework.
Educational information — not professional advice. Manufacturer instructions and a qualified installer's assessment of your specific subfloor should always take priority over general guidance. Last verified: 23 July 2026. See our Disclaimer & Terms.