Tiling Over A Laminate Countertop, continued
Setting the Tile
The first step in preparing a bonding bed of thinset over the
Ditra is to use a flat steel trowel to completely fill the
square recesses in the surface (Figure 3). Once I've filled the
mat, I add more thinset and spread it with a 1/4-inch
Figure 3.Once the tile layout has been fine-tuned
(top), more thinset is troweled into the waffle-patterned
surface and onto the exposed edges of the countertop, which
were previously stripped of their laminate self-edging
As in applying the thinset bed beneath the membrane, I make a
point of combing the mortar into a uniform pattern of parallel
ridges. This is added insurance against bond failure, because
the open ridges provide uniform support and prevent the
formation of air pockets. All this takes a lot of cement --
plan on using about half again as much as you would use in a
similar installation without the mat.
Counter tile and nosing.
After troweling more thinset onto the exposed countertop edges,
I'm ready to begin setting tile (Figure 4). Whenever possible,
I like to start my layout with full tiles at the edges and ends
of the counter, and that's the approach I took with this
L-shaped kitchen (see "Layout Tips," below).
Figure 4.Full tiles are set from an outside corner
of the layout toward the sink cutout. Installing a piece of
nosing against one edge of the corner tile determines how much
the remaining tiles should be held back from the edge to
accommodate the remaining nosing (top). Nosing pieces are
subject to hard knocks, so they're generously back-buttered to
ensure that they're thoroughly embedded (bottom).
To install the nosing pieces, I first coat the substrate, then
generously back-butter each piece with thinset to ensure
complete embedment. I take extra care with this step, because
poorly aligned nosing can make an otherwise well-done
installation look sloppy. The best way to keep everything in
line is to eyeball the trim lines as you do when selecting
lumber for straightness. There's more than enough time to tweak
the lines after initially bonding the tile, so there's no
excuse for gross irregularities.
The nosing pieces also have to withstand more abuse than any
other area of the countertop. If they're properly set to begin
with, they'll never loosen, but there's a good chance that one
or two edge pieces will be chipped by accidental impact
somewhere down the line. I always order a few extra pieces for
the job and tell my client to label them and store them in a
safe place, so they'll be available when the original style or
color has been discontinued.
Installing the backsplash. The tile backsplash in this
kitchen matched the countertop (with the addition of an
occasional decorative tile) and was aligned on the same grid.
Unlike a countertop, a backsplash isn't subject to standing
water, so the tiles can simply be adhered to the wall with
mastic. For mounting tile on wallboard, I use Durabond D-2001
Multi-Purpose mastic, which is a water-based adhesive with good
initial grab that provides a strong and permanent bond when
In remodeling applications, though, the strength of the mastic
bond will be limited by the strength of the bond between the
wallboard and any existing wall covering. In this case, the
backsplash area was covered with two layers of wallpaper. To
ensure that it was bonded to the wallboard well enough to tile
over, I coated the wall with mastic and let it "soak" for a
half-hour (Figure 5).
Figure 5.To prepare the wallpapered wall for a
tile backsplash -- which will be fastened directly to the
wallboard -- the author first coats the area with a water-based
mastic (top). Poorly bonded areas of wallpaper bubble away from
the wallboard and are easily scraped off with a small trowel,
leaving an acceptable tile base (center). The backsplash tiles
are then attached to the wall with more mastic
A few areas blistered up and I tore them away, exposing the
wallboard beneath. Once those loose areas were removed, I
attached the backsplash tiles to the exposed wallboard and
remaining well-bonded wallpaper with more mastic, which I
spread and combed with a 3/16-inch V-notch trowel.
Grouting and Sealing
I use a latex-modified grout in a color that complements the
tile background. Dark colors are preferable because they're
least likely to show dirt. Because smooth-struck joints are
easier to keep clean, I strike the newly filled joints with a
Nothing looks worse than sloppy corners and overflowing grout
lines, so I also take the time to cut excess grout out of the
corners -- where the wall meets the counter, for example, as
well as along the top of any finished edge. A 2x5-inch
rectangular margin trowel or putty knife works well for
After sponging the excess grout from the face of the tile, I
let the tile dry for ten minutes or so until a surface haze
develops. Rubbing the tile with a clean, dry rag removes the
haze and brings the tile to a nice shine. The following day, I
give the job a quick cleaning with a light tile cleaner. Glazed
tile buffs up nicely.
Finally, I apply a high-quality grout impregnator-sealer.
Don't cut corners here -- using the best sealer you can find is
cheap insurance against problems and callbacks later. I've had
good results with MiraSeal 511 Porous Plus (Laticrete,
800/243-4788, www.laticrete.com). I give every joint
three coats, allowing at least four hours between coats.
Although even this doesn't guarantee that the tile and grout
will stay clean, it does protect the grout from staining. If
the joints are struck smooth and then sealed well, the
homeowner should be able to clean away nearly any kind of
common dirt or grime. Because continued exposure to food acids
and household cleaning products will eventually reduce the
sealant's effectiveness, it's a good idea to reapply a coat of
sealer every two years or so.
Tom Meehanand his wife, Lane, own Cape Cod
Tileworks in Harwich, Mass.