Installing Your Laminate Flooring
Well-planned transitions are key to a good-looking installation
There are two basic types of laminate flooring: square or rectangular tiles,
which are usually made to simulate stone or ceramic tile; and plank
flooring, which resembles wood. In both cases, the laminate surface is
bonded to a substrate of medium-density fiberboard. The individual planks or
tiles have tongue-and-groove edges that are glued together and held with
special strap clamps, resulting in a smooth, stable, gap-free floor.
The biggest difference between laminate flooring and traditional flooring
materials is that laminate flooring is fastened to the subflooring only by
gravity and allowed to "float" on a thin layer of foam underlayment.
Quarter-inch expansion gaps at the edges of the floor allow it to expand and
contract with seasonal changes in temperature and humidity.
Generally speaking, the installation instructions supplied by manufacturers
are pretty good -- they're enough to get you going, at least. But they leave
out a lot of the tricks and fine points that make the difference between a
so-so installation and a really professional job.
Preparing the Subfloor
One of the great things about a floating laminate installation is that it
can be put right on top of many existing materials, including wood, vinyl,
and concrete. It can even be applied over some types of carpeting, such as
short, dense commercial carpet. In most cases, though, the carpeting will
have to come up anyway, so the subfloor can be adequately prepared. Soft,
thick carpeting always has to be removed. Laminate can go over wood flooring
that has been installed over joists, but existing hardwood that's glued to
concrete has to be torn up, because the required vapor barrier under the
laminate could create a moisture lock and cause the wood to rot or develop
|Laminate flooring can
be applied over a variety of substrates, including existing flooring
materials, as long as the surface is flat enough. Surface irregularities
that exceed 3/16 inch in a 6-foot span must be filled or cut down.
Acrylic- or latex-fortified cement-based floor patching material used to
fill low spots should be tapered to a feather edge.
- Building up. Laminate isn't a
structural material, so it can't bridge gaps or low spots. Each
manufacturer specifies the maximum permitted height difference between
high and low spots -- typically 3/16 inch over a 6-foot span. To check the
floor for level, use the same 6-foot aluminum straightedge (see Figure 1,
above). Once The low spots are identified, fill them with acrylic- or
latex-fortified cement-based floor patching material, which adheres well
to concrete and existing vinyl, as well as plywood and OSB. Smaller low
spots are easily built up with overlapping layers of 15-pound felt (Figure
You will also need shims of different thicknesses and widths, which often
come into play around doors and entryways.
|Minor low spots can
be corrected with several layers of 15-pound felt (top). Cutting each
successive piece smaller than the one before builds up the greatest
thickness in the center and tapers the edges. If necessary, the felt can
be taped in place until the weight of the laminate floor holds it in
- Lowering high spots. High
areas on joisted floors usually take the form of humps or ridges running
the width of the floor. Coarse sandpaper in a floor edger with a dust
collection system works very well for high spots on wood or plywood. On a
vinyl floor, outline the high spot with a grease pencil and score the
material at close intervals with a sharp utility knife, then cut it down
with a four-inch razor-blade scraper. It's usually not practical to cut
down high spots in concrete. Instead, build up the rest of the floor with
Vapor Barriers and Underlayment
When laminate flooring is installed directly over concrete or vinyl-covered
concrete, all laminate flooring manufacturers require a poly vapor barrier
between the subfloor and the foam underlayment. (Some manufacturers offer a
"two-in-one" underlayment that also serves as a vapor barrier.) Each
manufacturer provides its own proprietary brand of 6-mil poly. There's
probably little difference between them, and it can be tempting to use
leftover poly from one job under a different brand of laminate; but to
prevent possible warranty problems, avoid mixing materials from different
manufacturers. Adjacent sheets of poly should overlap by at least
Most manufacturers offer a choice of standard-grade foam underlayment or
a denser premium grade (Figure 3). Prices vary from one manufacturer to the
flooring manufacturers require a poly vapor barrier if the laminate will
be applied over a concrete subfloor. Adjoining sheets of poly should be
taped in position and must overlap by at least 8 inches (top). The vapor
barrier is followed by a foam underlayment that provides cushioning and
compensates for any remaining irregularities in the subfloor. Pergo
offers the choice of a standard-grade underlayment (Photo2 on top) or a denser premium-grade material (underneath).
The better-quality underlayment is recommended, because it provides
better sound deadening and a more solid feel underfoot
Layout, Gluing, and Clamping
The usual floor layout rules apply to laminates: Center the tiles or
planks on doors or in hallways, stagger joints between planks by at least 8
inches, and avoid slivers and U-shaped cutouts. Gizmo III laser --
which has a 90-degree function -- can be used to make sure that the initial layout is
straight and square to the room. Cut and dry-fit the first three courses
before start gluing to make sure that everything lines up the way you want
it (Figure 4).
||The first three rows of
flooring are cut and dry-fitted to ensure an accurate and attractive
layout. Note that the foam underlayment, unlike the vapor barrier,
fits closely together but does not overlap.
Glue joints and direction changes. It's
important to use enough glue. A continuous bead should be applied to the
grooved side of each plank or tile (Figure 5); and when the joint has been
tapped together and clamped, a thin line of squeeze-out should appear along
the entire joint. Some brands have slightly different gluing procedures; for
example, the directions may call for applying a bead of glue to the top of
the groove and the bottom of the tongue. Depending on the manufacturer, the
squeeze-out is either scraped off after it has partially set or immediately
cleaned up with a damp rag.
grooved half of each joint between tiles or planks is carefully filled with
a proprietary glue. Failure to use enough glue is the most common cause of
laminate floor problems. Squeeze-out should be cleaned up according to the
manufacturer's directions -- in the case of the Pergo floor shown here, by
wiping the joints immediately with a clean rag squeezed in a bucket of warm
The gluing and assembly process starts at one corner of the room, where a
section several tiles or planks long and wide, with the grooves facing the
walls, is glued, clamped, and allowed to set up for an hour (Figure 6). This
provides a solid base to build onto one piece at a time, loosening and
retightening the clamps as pieces are added.
Proprietary strap clamps secure the first rows of flooring (top left). Clamps can
be adjusted to alter the spacing between the edge of the flooring and the
adjacent wall to compensate for any irregularities in the framing. A
carefully aligned initial strip of flooring several tiles wide is glued,
clamped, and allowed to set up for an hour. Clamps are then loosened and
retightened as needed to place additional tiles (top right).
Especially when working with tile-type flooring, check the alignment
often, because any irregularities that creep in at the start will get worse
as you move along. To maintain proper pressure on the joints, keep the
clamp straps neatly aligned with the seams between tiles. As in laying
hardwood flooring, a slip tongue can be used to change direction when needed
to keep an efficient work pattern (Figure 7).
are typically installed from left to right, beginning with a grooved side
against the wall. Slip tongues are used to change direction where needed to
avoid an inefficient "backfill" installation.
There are several ways to conceal the quarter-inch expansion gap where the
flooring meets kitchen or bathroom cabinets. The most popular approach is to
enclose the cabinet base with base shoe or quarter-round molding, which is
coped or mitered at the corners (Figure 8). If desired, real wood molding
can be stained or painted to match the
cabinet, or a laminate-faced molding that matches the floor, available from
the flooring manufacturer.
Quarter-round trim strips are fastened to cabinet bases to conceal the
required 1/4-inch expansion gap between flooring and base. The kickspace can
be finished with vinyl cove base.
To avoid impairing the flooring's ability to expand and contract, the
molding should be nailed only to the cabinet base, not the floor. An
air-free brad nailer can be used for this job.
To eliminate the need for quarter-round at the base
of the toe kick, scribe the combined thickness of the flooring and
underlayment on the outside corners
which are then slightly undercut and cleaned
out with a chisel.
||Leaving a small amount of extra
material in the corner of the adjoining L-shaped tile lets the flooring
dive under the corner for a clean look with no visible gap.
The expansion gap in the kickspace is covered with vinyl cove base, which is cut off flush with
the side of the cabinet. The gap at the side is concealed by quarter-round
that terminates just short of the corner with a back cut.
Another method, which is often used in bathrooms, does away with the
quarter-round in the toe kick while still leaving a clean, gap-free corner
(Figure 9). This requires undercutting the cabinet base at the outside
corners and takes a little more time, but it's made much easier with a good
Baseboards and Room Perimeter
It's especially important to leave an adequate perimeter expansion space in
new construction. Framing lumber, drywall, and fresh concrete emit a lot of
water vapor, which can cause a floor to buckle if it doesn't have room to
But it's also important to prevent water from making its way into the
expansion space and damaging the floor. In wet areas like bathrooms, the
expansion gap and the area under the toilet flanges must be filled with 100%
silicone caulk. The same goes for potentially wet areas in kitchens, such as
along cabinets below a sink or dishwasher. Install moldings immediately
after filling those areas with sealant, because once the silicone sets up, it
often has high spots that can keep the molding from sitting flat.
Baseboard options. The simplest way to
deal with baseboards is to bring the laminate up to the existing base and
cover the gap with quarter-round or base shoe. This is an easy and
inexpensive approach. But this method does have a drawback. With
narrow baseboard, the built-up height of the floor and the added height of
the shoe molding can make the base seem awkwardly small and "buried." If the
base is only 2 1/4 inches high to begin with, it can end up looking very
skinny by the time you're done.
A more labor-intensive option is to reuse the original baseboard by removing
it before the flooring goes down and reinstalling it afterward. If it's too
much trouble to save the old base, it can be replaced with matching new
material. Either way, the baseboard itself covers the expansion gap, so
there's no need to add a base shoe. A drawback to this method is that the
reset or replaced baseboard will sit about 3/8 inch higher on the wall than
it did originally, so it won't match the height of the base in areas where
the floors haven't been covered with laminate. Plinth blocks or
some other additional trim can be used to conceal the height difference where the two
Pergo makes a very versatile piece of trim called end molding, which is an
L-shaped piece that is useful for trimming around door thresholds, hearths,
and even carpeted stair risers (Figure 10).
Transitions between laminate flooring and carpeted areas are trimmed with a
two-piece carpet reducer (Figure 11). A similar hard-surface reducer is used
for transitions between laminate and vinyl, wood, or tile.