line up the starter row to it. Because you don’t
face-nail a starter course in the middle of a room,
Using a piece of scrap to avoid damaging the tongues,
screw temporary blocks—scrap flooring is fine—
drive the boards snugly together before nailing them. The
along the chalkline to keep starter-row boards in
friction between the tongues and the grooves will usually
hold them during nailing.
place. Otherwise, they could drift as you drive
nails through the tongues. Nail down five or six
rows, before removing the temporary blocks.
Next, add wood splines (also called slip
tongues) to the grooves of starter-row boards,
574 Chapter 20
If boards are slightly warped or tongues and grooves are a
Glue the last row of boards, especially those at the base of The first and last rows of tongue-
bit swollen, use a thick screwdriver as a lever to draw them a cabinet. Only one edge will engage the board next to it, and-groove floorboards are usually
together. Hammer the screwdriver point into the subfloor
and there’s often not enough room to drive nails.
face-nailed, here with a pneumatic
to get some traction.
finish nailer. Draw boards tightly
together with a flat bar.
which most flooring stores carry. Adding splines
allows you to blind-nail toward the opposite wall
as well. Glue splines to board’s grooves, using
scrap flooring to drive the splines snug without
damaging them.
Installing the rest is straightforward. To speed
the installation and ensure that board ends are
staggered at least 6 in. between rows, have a
helper rack (spread out) floorboards so you can
quickly tap boards into position with the flooring
mallet and nail them down. Floorboards come in
regular lengths from 12 in. to 36 in. So to create a
random joint pattern, use board remnants with
irregular lengths to start rows.
Continue blind-nailing boards every 10 in. to
12 in., checking periodically to make sure the
rows are straight. If milling irregularities or
warping prevents boards from seating correctly,
use a large flat screwdriver to lever the boards
snug, as shown in the top left photo. Set aside
Whenever there’s a tricky transition or a complex
boards that are too irregular to use; professional
shape to cut, either scribe the shape or create a
installers typically order 5% extra to allow for
template to transfer the shape to the floorboards, as
warped or poorly milled boards and waste.
this installer is doing.
As you approach within a foot or two of the
opposite wall or next to a base cabinet, you won’t
have room to use the pneumatic flooring nailer,
so switch to a pneumatic finish nailer. Nor will
you have room to swing your flooring mallet, so
use a pry bar to draw the boards’ edges snug. As
Flooring
575
you get within 6 in. to 8 in. of the wall, measure
the distance remaining, including 3⁄4 in. for an
Wood Flooring over Concrete
expansion joint. In most cases, you’ll need to rip
down the last row of floorboards. If they are less
Before purchasing wood flooring for installation over concrete slabs or in below-
than 1 in. wide, first glue them to the next-to-the-
grade areas such as basements, check the warranty to see if such installations are
last row and install the two rows as a unit. Or, if
allowed. When allowed, most require that excess moisture conditions be corrected
you’re installing floorboards of varying widths,
beforehand. in general, engineered wood flooring is a better choice than solid-wood
rip down a wider board. The last row of boards
flooring in such locations because engineered flooring is more dimensionally stable.
should be face-nailed and glued to the subfloor
When solid-wood flooring is installed over concrete, the slab is typically covered
as well. Finally, install prefinished transition
with a 6-mil polyethylene vapor barrier, with 2x4 sleepers (on-face) spaced every 12 in.
pieces such as thresholds, reducer strips (strips
to 16 in. over the plastic; power-actuated fasteners then attach the sleepers to the
that taper to accommodate differing floor
slab. although it’s possible to nail 3⁄4-in. t&g flooring directly to sleepers, it is likely to
heights), and so on. When you’ve sanded and fin-
deflect. Most flooring manufacturers specify a 3⁄4-in. plywood subfloor, with panels run
ished the flooring, reinstall the baseboards.
perpendicular to the 2x4s, a 1⁄8-in. gap between panel edges, and a 1⁄2-in. expansion
Store extra flooring in a dry location. If the
space around the perimeter of the subfloor.
flooring has a warranty, file it in a safe place,
alternatively, some building scientists argue against using plastic vapor barriers and
along with the flooring’s code number and floor
for covering concrete surfaces with semipermeable, moisture-tolerant insulation panels,
care information.
as discussed on p. 257. they suggest placing 1-in.-thick expanded polystyrene (EPS)
panels on the concrete floor. EPS’s compressive strength is sufficient that you can then
“Floating” an Engineered
cover it with a 1⁄2-in. plywood floor—there’s no need for sleepers.
Wood Floor
Engineered wood and plastic-laminated flooring can be nailed or stapled to wood
As explained earlier in the chapter, engineered
subflooring, glued directly to a slab, or “floated” over it. Floating systems typically call
wood flooring can be thought of as a specialized
for floorboards to be glued or attached to each other, rather than to the subfloor or
type of plywood, usually five to seven plies thick,
slab. Many systems feature proprietary underlayments that block moisture and cold and
with a hardwood veneer face layer—also called
cushion the flooring so you feel less like you’re walking on concrete. Cosella-dörken’s
the wear layer. Because it is more stable dimen-
dElta®-Fl underlayment is a dimpled plastic membrane, and other systems employ foam
sionally than solid wood, engineered flooring is
or felt pads. Floating systems can be used over slabs with radiant heating, as well.
little affected by shifts in temperature or humidi-
ty. When used with an appropriate underlayment
layer, it has been installed over a wide range of
substrates, including plywood, particleboard,
concrete, resilient flooring, and even ceramic tile.
This flooring’s wide usage has led to diverse
methods of installing it, including gluing it to a
substrate, nailing or stapling it, and floating it—
in which individual boards are snapped together
or glued together but that, as an assembly, are
not attached to the subfloor. This section looks at
one way to float an engineered wood floor.
Floating a wood floor is an attractive option for
many reasons:
�
�� It is relatively simple to install and
requires few specialized tools.
It is the preferred method for installing a
floor below grade—say, in a basement. It is
also arguably the simplest way to install
flooring over concrete.
It is one of the few acceptable ways to
install wood flooring over particleboard—
which makes it an ideal choice to upgrade a
floor that was previously carpeted.
It is the preferred installation method
Every box of boards has variations in color and grain, so take boards from several boxes as you
over subfloors with radiant heat because there
install them. Stagger end joints at least 12 in. to 24 in. in adjacent rows. If end joints line up every
are no flooring nails or staples to puncture
third or fourth row, it won’t be too noticeable.
radiant tubing or electrical cables.
576 Chapter 20
Heed the maker. The usual warnings about buy- from online flooring suppliers. Here are the other
P R O T I P
ing quality and reading the manufacturer’s instal-
necessary items:
lation instructions are doubly true when it comes
Layout: measuring tape, chalkline (taut
When examining displays of
to engineered wood flooring. The integrity of the
string), and straightedge (a flooring board
engineered wood flooring at a
product, the thickness of the wear layer, and the
will do).
supplier, scratch the flooring
durability of the finish all argue for buying pre-
Cutting: chopsaw with a fine crosscut
with your thumbnail. if that
mium flooring from a reputable company. Wear
blade for cutting across boards, tablesaw with
leaves a white streak on the sur-
layers vary from 1⁄16 in. to 1⁄4 in. thick. Supposedly, a fence for ripping boards, sabersaw for
face, be skeptical about the fin-
wear layers 1⁄8 in. to 1⁄4 in. thick can be refinished
complex cuts around pipes and the like, and
ish’s durability.
two to five times, though it would take a very
undercut saw or an oscillating multitool for
light touch to do so successfully.
trimming the bottoms of door casings.
Miscellaneous: pry bar, hammer, staple
ordEring, aCCliMating,
gun or hammer tacker, utility knife, carpenter’s
and Storing Flooring
square, pencil, safety glasses, work gloves, and
broom or vacuum. Optional: finish nailer.
After calculating the square footage of the
room(s) to be floored, add 5% to 7% for waste. If
Materials: approved adhesive or glue for
you will be installing the flooring in a diagonal
joining boards, cardboard shims, sponge and
pattern, add 10%. It’s helpful to have a carton on
rags for wiping up excess glue, construction
hand for repairs later, in the event that the prod-
adhesive for affixing thresholds, and foam or
uct line is discontinued.
felt paper underlayment. Replacement
Have flooring delivered after drywalling and
baseboards or trim if originals are destroyed
painting are complete. Ideally, your order should
removing them.
arrive five to seven days before you plan to install
it so it has time to acclimate. Flooring makers
PrEParing tHE rooM
recommend room temperatures of 60°F to 80°F,
If you float engineered wood flooring, you can
with relative humidity of 35% to 65%. If there’s
install it over pretty much any substrate—above
new plaster or concrete present, it should have
or below grade—as long as that substrate is sta-
cured for at least 60 to 90 days.
ble, sturdy, dry, and flat. Again, follow the manu-
Checking the order. When the shipment arrives, facturer’s specs that come with your flooring to
set aside cartons that are damaged, damp, or
protect the warranty. This section describes float-
delaminating. Open them at once and look for
ing engineered wood flooring over particleboard
crushed edges, cupped boards, water stains, blis-
or plywood, typically 5⁄8 in. or 3⁄4 in. thick, nailed
tered finishes, and so on. If you see any of these
to 2x10 floor joists spaced 16 in. on center.
conditions, reject the shipment. If cartons look
OK, don’t bother opening them until you are
ready to install the flooring. But if you reject a
shipment, you must do so before installation. You
can’t do so afterwards, piecemeal.
Wood is irregular, however, so expect to cut
off occasional sections with small knots. One
other thing to note when opening cartons: Most
boards should be 4 ft. to 8 ft. long. Too many
short boards will yield many more end joints,
which won’t look as good.
Storing flooring. When the flooring arrives,
stack cartons flat in the middle of the room. Do
not stand cartons on ends or sides, which may
damage the tongue-and-groove edges. Do not
store cartons in an unheated garage, directly on
concrete, or in direct sunlight.
toolS and MatErialS
You need only two specialized tools to install
engineered wood flooring: a hard-plastic tapping
Thorough prep work is essential. The substrate must be flat, well attached, and clean. Pry off
block and a metal pull bar. Both are available
baseboards, and trim the bottoms of door casings so flooring can slip under them. Here, the
installer uses a scrap of flooring as a depth gauge beneath an undercut saw. You could also use an
oscillating multitool.
Flooring
577
Remove obstructions. If the room is carpeted,
Next, measure out from the chalkline to the
remove it and its padding, then pry up nailing
opposite wall to determine if the room is square.
strips and any staples stuck in the subfloor.
If the room is not square, you will need to scribe
Because the new flooring will run to within 1⁄2 in. the floorboards along one wall—preferably along
of finish walls, also remove baseboards, shoe
the least visible wall. In the photo sequence, the
molding (if any), and doorway thresholds, as well room was square, so there was no need to scribe
as heat registers, baseboard heater end caps, pipe floorboards.
escutcheons, and so on. You will also need to
Lastly, measure the room’s width—from the
P R O T I P
trim the bottoms of door casings so flooring can
starting wall to the opposite wall—and divide the
slide under them. The best tool for this last oper-
room’s width by a board’s width. Engineered
after stapling underlayment,
ation is an undercut saw, as shown on p. 577; an
floorboards vary in width, but the most common
use a utility knife to cut open-
oscillating multitool with a wood-cutting blade
are 6 in. or 7 in. wide. If yours are that width and
ings fo
r pipe risers and heat
(see p. 49) is even faster.
the last row would be less than 2 in. wide, split
registers. When you’re in a floor-
the difference. In other words, trim down the
laying rhythm, it’s easy to forget
Secure the subfloor. After vacuuming it well,
first row so that both the first and last rows will
and floor over registers.
walk the subfloor (or floor) and note squeaks.
have roughly the same width.
Using ring-shank nails, nail down squeaky spots,
or, better, countersink wood screws into noisy
laying row one. Place cardboard shims every
boards. That done, use a straightedge to survey
2 ft. to 3 ft. along the wall to establish a 1⁄2-in.
the floor for high and low spots. Shaw® Floors’
expansion gap and, as needed, to create a straight
specs call for the substrate to be flat within 1⁄8 in.
surface for the first row of boards. To determine
of a 6-ft. span. Sand down high spots or fill low
the length of that first row, measure the length of
spots, using a cement-based leveling compound
the wall and subtract 1 in.—to allow 1⁄2-in. gaps
such as Ardex Feather Finish®, which is self-
at each end. Place boards with the grooved edges
drying and has excellent compressive strength.
toward the wall; tongue edges will face out into
the room. Apply glue to boards’ butt-end grooves,
Apply the underlayment. Again, follow the
fit boards together by hand, and snug them
manufacturer’s specs. Below-grade installations
against the shims along the wall. Tap board ends
over concrete, for example, can be quite exacting, together, using a pull bar. Then place a straight-
employing a seam-sealed 6-mil poly film vapor
edge along the tongues to make sure boards are
barrier used in tandem with an approved foam
lined up straight.
pad layer. Above grade, tar paper is often used as
Note: Place shims behind end joints in the
underlayment, although quality installations
first row, too.
favor a foam layer because it cushions floating
floor systems, mitigates substrate irregularities,
don’t overglue. Board edges are machined to
and soundproofs to a degree. When stapling
fit tightly and are glued only to add stability.
foam underlayment, use as few staples as possi-
Apply glue to the bottoms of grooves, filling them
Renovation 4th Edition Page 133