Difficulty:- Intermediate
Time:- Novice: 8 hrs.- Experienced: 6 hrs.- Pro: 4 hrs.

What you will need


  • Broom
  • Tape Measure
  • Chalkline & Chalk
  • Jamb Saw
  • Drill & Drill Bits
  • Hammer
  • Nail Set
  • Table Saw
  • Jigsaw
  • Floor Nailer
  • Pry Bar
  • Mallet
  • Nail Gun


  • Hardwood Flooring
  • Barbed flooring nails
  • 15 lb. Roofing Felt Paper
  • Transition Strips

We Recommend:
Hardwood floor fastening systems by Porta-Nailer, Inc. (PNI)


  • nstall on or above grade, not below grade.
  • If you’ll be installing the floor yourself, you’ll want to use a set of nail guns to speed up the process.
  • Make sure you have an acceptable subfloor: 3/4in. CDX plywood is preferred and 3/4in. OSB is acceptable. Minimum 5/8in. CDX existing wood floor or tongue-and-groove solid wood subfloor also acceptable.

Installing Hardwood Flooring on a Concrete Slab

With the right subfloors, hardwood flooring can be installed successfully on either on-grade or above-ground slabs. Below-grade installation is not recommended. The slab must be flat and level with a trowel finish, free of grease, oil, stains and dust. New concrete is heavy with moisture, so test for dryness before beginning the subfloor. The National Oak Flooring Manufacturers Association recommends two choices in sub-flooring systems: plywood-on-slab and sleeper.


Begin by covering the slab with a vapor barrier.

Asphalt felt or building paper: First, prime the slab and apply cold, cut-back asphalt mastic with a notched trowel (50 sq. ft. per gallon). Allow to set for two hours. Unroll 15-lb. asphalt felt or building paper, lapping the edges 4″ and butting the ends. Over this, apply a second similar coating of mastic and roll out a second layer of asphalt or paper in the same direction as the first, staggering the overlaps to achieve an even thickness.

Polyethylene: Cover the entire slab with 4 to 6 mil polyethylene film, overlapping the edges 4″ to 6″, and allowing enough film to extend under the baseboard on all sides.

When moisture conditions are more severe, prime the slab and apply cold, cut-back mastic with a straightedge or fine-tooth trowel (100 sq. ft. per gallon). Lay 4 to 6 mil polyethylene film over the slab, overlapping the edges 4″ to 6″.

In either case, roll the film flat or “walk” it in, stepping on every square foot to ensure adhesion. Puncture bubbles to release trapped air.

Install the plywood after the vapor barrier is in place. Loosely lay a nailing surface of 3/4″exterior plywood panels over the entire area, leaving a 3/4″ space at the wall line and 1/4″ to 1/2″ between panels. Cut plywood to fit within 1/8″ near door jambs and other obstructions where finish trim will not be used. Lay plywood diagonally across the direction of the finished floor to help prevent cracks along panel edges.

Fasten plywood to the slab with power-actuated fasteners, securing the center of the panel first, then the edges, using nine or more fasteners.

Do not use power-actuated fasteners or concrete nails when radiant heat pipes are embedded in the slab. Instead, cut the plywood into 2´ by 8´ planks and score the backs 3/8″ deep on a 12″ grid. Lay panels in a staggered pattern with at least 2′long planks along starting and finishing walls. For systems other than radiant heat, the plywood planks may be glued to the plastic with asphalt mastic. Spread using a 1/4″ by 1/4″ notched trowel.


Flat, dry, preservative-treated 2″ x 4″ sleepers in random lengths (18″ to 48″) can also serve as a nailing base.

Begin by sweeping the slab clean, applying an asphalt primer and allowing it to dry.

Next, embed the sleepers on their flat faces in rivers of hot (poured) or cold (cut-back) asphalt mastic, in rows 12? on center, at a right angle to the direction of the finished flooring. Stagger the end joints, overlapping the ends 4″, with 1/4″ space between.

Before installing the floor, loosely lay an additional vapor barrier of 4 to 6 mil polyethylene film over the sleepers, overlapping the edges on top of the 2 x 4s. Avoid bunching or puncturing the film, especially between sleepers.

Nail the finished flooring to the sleepers through the film.

Follow these steps

Step 1: Lay Out the First Row

Mark the walls to show the location of the floor joists. For strength, run the strip flooring perpendicular to the joists. Start your layout at the longest uninterrupted wall that’s perpendicular to the joists. At each end of the wall, measure out the width of a floorboard, plus 3/4 in., and make a mark. Drive nails into the marks and stretch mason’s line between them to lay out the first row.

Step 2: Pre-Drill Holes for Nails

The first and last rows of flooring have to be nailed through the face of the boards. All the other boards are nailed through the tongue only. To prevent splitting face-nailed boards, drill 1/16-in.-diameter holes for the nails, 1 in. from the grooved edge. Space the holes so the nails hit a joist, or as directed by the manufacturer.

Step 3: Fasten the 1st Board

Align the first board with the layout line, with the tongue facing into the room. Put a 3/4-in. spacer against the adjoining wall, and slide the end of the board against it. Drive 6d or 8d flooring nails through the pilot holes, then drill additional pilot holes through the tongue. Countersink all the nails.

Step 4: Continue the 1st Row

Put the next board in place along the layout line. Seat the end tongue and groove into each other and push the two boards together for a tight seam. Nail down the board, moving down the row until you reach the side wall. Cut the last length to fit, leaving a 3/4-in. expansion gap, and nail it in place.

Step 5: Rack the Flooring

Spread the boards from several bundles across the room. Mix bundles, and mix shades, colors, and lengths, using the natural variety in the wood to create a random pattern. Lay out the boards in the order you’ll install them. Pros call this “racking the boards.” Flooring bundles tend to be uniform in color, and if you don’t rack them, you’ll create noticeable light and dark areas in the floor. Make sure you finish the process by arranging the joints so they are sufficiently offset across the floor.

Step 6: Install the Next Rows

Put the first board of the new row in place. Cut it, if necessary, so the end is offset from the end of the board in the previous row by a minimum of 6 in. Put the end against a 1/2-in. spacer and seat the edge snugly against its neighbor. Drill pilot holes in the tongues, then nail and countersink them through the tongues (but not the faces) to hold the boards in place. Work your way down the rows, one row at a time.

Step 7: Use A Flooring Nailer

Switch to a flooring nailer as soon as you can. After installing the second or third row, you’ll have enough room to get a flooring nailer between the wall and the board you’re placing. Position the nailer so it will drive a nail through the tongue of the board, then hit it with a mallet to shoot the nail through the tongue. Adjust the air pressure as needed so the nail countersinks into the tongue.

Step 8: Install the Remaining Rows

Work your way across the room, row by row, power-nailing the boards through the tongue. Leave a 3/4-in. expansion gap between the end board and the wall. Stagger the ends of the boards in adjoining rows by 6 in. and rack additional bundles as you go.

Step 9: Straighten Any Bowed Boards

Even the best flooring comes with pieces that are not perfectly straight. Set these aside initially; if these end up as extras, you won’t have to use them. If you must use a slightly bowed piece, drive a chisel into the subfloor and pry against the edge of the bowed strip to straighten it. If the piece is badly bowed, screw a piece of scrap to the floor about 1 in. from the strip. Tap a wood wedge into the gap, as shown, to straighten out the board.

Step 10: Framing Obstructions

Often a floor will meet an obstruction such as a fireplace or counter. If so, miter boards to create a border that frames the obstruction. Position the boards so the tongue or groove mates with the rest of the floorboards. Cut off the tongue if it’s on the edge that meets the obstruction. Apply the rest of the floor as you normally would, fitting the pieces into the frame as you go.

Step 11: Cutting Corners

Where the flooring meets a jog in the wall or a similar obstacle, cut corners to fit. Snug the piece of flooring against the obstacle and lay out the cut by marking where the edge of the obstacle meets the board. Allow for a 1/2-in. expansion gap at the end of the board and a 3/4-in. gap along the edges; make the cut with a jigsaw.

Step 12: Face-Nail the Last Rows

As you approach the wall on the far side of the room, it becomes difficult to use the flooring nailer. Once you don’t have enough room to swing the mallet, begin drilling pilot holes for face-nailing, but nail only when you’ve laid down all the boards.

Step 13: Cut the Last Row to Fit

You will probably have to cut the width of the boards in the last row to fit. Measure the space and subtract 3/4 in. for the expansion gap. Cut the boards to width on a tablesaw. Put the boards in place. Pry against a piece of scrap on the wall to seat the boards and close any gaps between them. Face-nail to hold the boards in place.

Step 14: Install the Trim

Install the baseboard and shoe molding to cover the expansion gap. Keep the lower edge of the baseboard even with the top of the floor, and nail the baseboard into the wall. Once the baseboard is in, set the quarter-round shoe molding on a piece of paper to keep it just a hair above the floor. Nail it to the baseboard, not to the floor or subfloor. Nail threshold or transition strips in place where the edge of the floor is exposed.