The flooring installation method decides how a floor sounds, how it handles moisture, and how it gets repaired years from now. Nail-down fastens boards to a wood subfloor. Glue-down bonds them to the subfloor with adhesive. Floating locks boards to each other without attaching them to anything. The right choice depends mostly on what is under the floor and which product you picked, not on preference.
What each installation method actually does
Nail-down: boards fastened through the tongue
Nail-down is the traditional method for solid hardwood. The boards are typically 3/4 inch thick, with a tongue on one edge and a groove on the other. A nailer drives a cleat or staple through the tongue at an angle. Spacing is typically every 6 to 10 inches along each board, with fasteners closer together at the ends.
The method needs a wood subfloor to hold the fasteners. Sound plywood or board subflooring works. A bare concrete slab does not. Often a layer of felt or rosin paper goes between the subfloor and the boards. It is used mainly as a moisture retarder and a slip sheet. Its effect on squeaks is limited, because squeaks come from the fastening and the condition of the subfloor.
Each board is pulled tight to its neighbor and pinned to the structure. That is why a nailed floor feels like part of the house.
Glue-down: boards bonded across the whole back
Glue-down means troweling adhesive onto the subfloor and setting each board into it. The adhesive starts to skin over, so we work in sections and watch the open time. Trowel notch size and spread rate matter, and they change with the product. This is one reason a glue-down job rewards an experienced crew.
It works over concrete and over wood subfloors. Most glue-down hardwood is engineered, because a layered core moves less than a solid board. Follow the adhesive manufacturer’s stated cure time, often a day or more, before normal traffic. Furniture often waits longer.
Floating: boards joined to each other
A floating floor is not fastened to the subfloor at all. The boards click or glue together at the edges and rest on a thin underlayment. Engineered wood, laminate and vinyl plank can all be floated. Much of our luxury vinyl plank installation work is click-lock for that reason.
The whole floor moves as one sheet, so it needs room. We leave a gap at every wall, pipe and cabinet base. The size is set by the manufacturer’s instructions, often 1/4 to 3/4 inch, and it is larger for bigger rooms. Baseboard or quarter round covers it. That gap is part of the reason for the debate over whether baseboards should come off during an install.
How the method changes the feel and sound
Walk across all three and you notice the difference in a few steps.
- Nail-down: solid underfoot, with a low thud. Squeaks show up when a fastener loosens or the subfloor shifts.
- Glue-down: typically the quietest and most solid. With the whole back bonded, there is little room for a hollow sound or a squeak.
- Floating: the most likely to sound hollow, especially over a hard, flat subfloor with a thin pad. A thicker pad softens the sound but can make the floor feel springy.
Weight is the other difference. A floating floor has to stay free to move. Heavy fixed items, such as kitchen cabinets and islands, should not sit on top of it. We lay the floor up to them and leave the gap. Nailed and glued floors are less picky about this.
Doorways also differ. A floating floor cannot be pinned in place, so long runs and doorways often need a break or a transition. Our guide to transition strip types covers what fits where.
How the method affects repairs and refinishing
This is where homeowners most often wish they had asked sooner. The method you choose now sets your options in fifteen years.
A solid nailed floor has typically about a quarter inch of wood above the tongue. That allows several sandings over its life. A damaged board can be cut out and a new one woven in. Whether yours needs a light buff or a full sand is covered in screening and recoat vs full refinish. The sanding itself falls under our hardwood floor restoration service.
Glue-down engineered flooring depends on its wear layer, which typically runs from about 1 mm to 6 mm. A thin layer may allow one light sanding or a recoat only. Replacing a single glued board is possible, but it means cutting it out and scraping off adhesive. It is slower and messier than a nailed repair.
Floating floors repair differently. Replacing a click-lock plank in the middle of a room depends on the product. One option is unlocking every row between the wall and the damaged plank. Installers also often cut out the damaged plank, trim the locking edges of the replacement and glue it in, with no disassembly. Some floating wood floors can be refinished, depending on the wear layer. Laminate and vinyl plank cannot be sanded at all.
What the house decides for you
Preference matters less than conditions. Three things settle most jobs.
The subfloor type
A wood subfloor keeps all three methods open. A concrete slab removes nail-down unless a wood subfloor is built over it first. That leaves glue-down or floating.
Concrete holds and releases moisture slowly, so we test the slab before choosing anything. A surface test or an in-slab probe can both be used. Wet concrete causes the failures we take most seriously. Glue-down adhesive can lose its bond and boards lift. A floating floor can trap moisture underneath and cup. No method fixes a wet subfloor. It has to be dry first.
A wood subfloor needs a moisture check too. We compare its reading to the boards going on top.
How flat the subfloor is
Most products call for a subfloor flat to about 3/16 inch over 10 feet, and that applies to every method. Floating click-lock floors are the least forgiving. A dip lets the floor flex, and flexing wears the locking edges and can cause creaks. On glue-down, a hump telegraphs through the boards and a dip leaves a hollow spot. Nail-down is only slightly more forgiving. Nailing over a dip can still leave hollow spots and squeaks.
Fixes include sanding down high spots, grinding concrete, and patching or leveling low areas. That prep is part of the job, not an extra.
Humidity and movement
Wood floors do best with indoor humidity of roughly 30 to 50 percent. Atlanta summers push past that, and winter heating pulls well below it. Each method handles the swing differently. A nailed floor moves board by board. A glued floor is held in place by the bond. A floating floor moves as one unit and needs its wall gap. Our post on how Atlanta humidity changes hardwood floors by season explains what that looks like through the year.
Stairs are a separate case. Hardwood treads are fastened and glued, not floated. If a nailed main floor needs to meet a staircase, we handle that connection as part of the stair work.
A decision sequence: check this first, then this
This is the order we work through on a walk-through. Skipping a step usually means re-doing one later.
- Identify what is under the floor. It might be a wood subfloor, a concrete slab, or an old floor. A slab rules out plain nail-down right away.
- Test moisture. Test the slab, or meter the wood subfloor. If readings are high, stop. Find the source before any method is chosen.
- Check flatness. Lay a straightedge across it. Anything beyond roughly 3/16 inch over 10 feet needs grinding, patching or leveling.
- Match the product to the methods it allows. Solid 3/4-inch hardwood is typically nailed. Engineered wood may allow nailing, gluing or floating, depending on its build. Laminate and click vinyl plank float.
- Look at the room. Note heavy cabinets, long runs, doorways, stairs and any radiant heat. Radiant heat limits both the method and the product, so settle it before ordering.
- Think about the long game. If you want to sand the floor in the future, the wear layer decides it. Choose the method and product together.
- Plan the schedule. Wood often needs a few days to two weeks in the house first. Add the adhesive cure time if gluing, and the time before furniture returns.
Settle the method before the boards arrive
The method should be decided before material is ordered, not after it is on the porch. A floor bought for nailing cannot always be glued, and the reverse is true too. Our guide on choosing new wood flooring helps with the product side. For the job itself, what to expect during a new floor installation walks through the days on site. If nailing is the plan, what to avoid during hardwood floor installation lists the mistakes that cause trouble later.
Homeowners in Johns Creek often ask us about this when a slab-on-grade room, a finished basement or a main level of mixed subfloors forces more than one answer in a single house. That is normal. One method per house is not a rule. Each area can get what suits what is beneath it.
Across solid and engineered products, our hardwood flooring service covers all three methods, wherever the product allows.
Not sure which method your subfloor allows? We have served the north Atlanta suburbs since 2008, and we are licensed and insured. Request a free estimate or call 404-578-0926, and we will check the subfloor before recommending anything.
Frequently asked questions
Not directly, because nails and staples need wood to grip. Over a slab, the usual choices are glue-down, a floating floor, or a wood subfloor built over the concrete first. All of them start with a moisture test on the slab.
It depends on the subfloor and the room. Glue-down typically feels more solid and quiet, while floating goes down faster and can be lifted more easily. Many engineered products allow either method, so check what the specific product permits.
The manufacturer’s instructions set it, often 1/4 to 3/4 inch, and the gap is larger for bigger rooms. It lets the floor expand and is hidden under baseboard or quarter round.
A floating wood floor sometimes can, if the wear layer is thick enough to sand. Laminate and vinyl plank cannot be sanded at all, so the wear layer is the first thing to check.
Keep reading
- Advantages of Hiring Professionals for Hardwood Floor Installation
- Options for Engineered Hardwood Floors
- Can You Refinish Engineered Hardwood Floors? What to Check First