ment, framing must be exact:
Fortifiber’s Super Jumbo tex
rials are solid. Particleboard countertops often
Subfloors and countertops must be
60 Minute will also keep shower
deteriorate from sink leaks and dishwasher
substrates dry even if you take
level and flat to within 1⁄8 in. in 10 ft. that
steam. If there’s extensive rot or subfloor delami-
hour-long showers. Polyken®
is, no high or low points greater than 1⁄8 in.
nation, replace failed sections, as described in
Foilastic®, a peel-and-stick
chapter 8. To test for deflection, thump walls
of level.
flashing, does a good job of seal-
with your fist, or jump on the floors. If you see or
Walls must be plumb and flat to within
ing shampoo niches, pipe cut-
1
feel movement, there may be structural deterio-
⁄8 in. in 8 ft.
outs, and troublesome joints
ration or, more likely, the substructure may be
as you might expect, standards are more
around kitchen counters (see the
undersize for the span.
tolerant for mortar-bed installations, which
top drawing on p. 473).
are thick enough to accommodate less-than-
PrePPing the rooM
perfect framing. Mortar-bed tolerances are
Tiling will go faster and look better if you first
roughly double the thin-bed specs given here.
remove fixtures and other obstructions so that
a good place to check on these and other
you can lay a continuous field of tile. This is a
questions is www.tileusa.com, the website
good time to relocate or enlarge electrical boxes,
of the tile council of north america. each
install thresholds, or cut a little off the door bot-
year the site updates its handbook of tile-
toms so they don’t scrape when tiling raises the
installation standards, spelling out accept-
floor level. For information on disconnecting and
able materials and structural requirements for
installing plumbing fixtures, see chapter 12.
each type of setting bed.
460 chapter 16
adequately. In fact, you can buy extrathick wax
rings for such situations.
But if the tiled floor will be more than 1⁄2 in.
Wax ring
Tile
zzzzzz tile height at toilet
higher than the closet flange (which may result
if you install a mud bed or backer-board setting
Thinset
Closet flange
bed), replace the flange and set the new one
Backer
higher. If waste pipes are plastic, cut off the exist-
board
ing bend-and-flange section and cement on new
components to give you the flange height you
need. This is easier said than done, however: If
there’s no room to maneuver new pipes, you may
need to cut into flooring or framing. Many
plumbers prefer to build up existing flanges by
Old
Plywood
flooring
stacking 1⁄
substrate
2-in. plastic flange extenders (the same
diameter as the flange), caulking each with sili-
1/8-in. gap
Thinset bonds
cone, and using long closet bolts to resecure the
backer board
Closet bend
to old flooring.
toilet base. But check your local plumbing code
to see if this method is allowed.
If drainpipes are cast iron, you may want to
hire a plumber to replace flanges that are too low
or waste pipes that have deteriorated. There may
Ideally, the top of the toilet flange should be the same height as the
not be enough room to cut out pipe sections, or,
finished floor. If not, consider the options outlined in the text.
in the case of deteriorated pipes, there may also
be rotted framing or subflooring to attend to
To remove a showerhead assembly, gently pry
before replacing pipes and fixtures.
the escutcheon from the wall (it may be seated in
Removing a sink may be advisable before retil-
plumber’s putty). Then wrap a rag around the
ing a countertop. The method depends on the
chrome gooseneck pipe, and use a pipe wrench
sink type: whether countertop, pedestal, or wall
to unscrew it. (The rag prevents the wrench from
mounted. For each, shut off the water, then dis-
gouging the chrome finish.) Removing valve han-
connect supply lines and drainpipes.
dles is slightly more complex because you must
Countertop sinks vary in their attachment. If
first unscrew valve handles from valve stems,
you are retiling a countertop, you must remove a
and those screws are frequently hidden behind
self-rimming sink because its lip rests atop the
decorative caps. Once you’ve removed handles
P R O T I P
tile. However, you may want to remove other sink and escutcheons, wrap the exposed valve stems
types to better match the color of tiles, upgrade a with plastic so their threads don’t get fouled
if the thicker new walls
tired old sink, and so on. Most sinks are held in
with mortar.
reduce the visible profile of
place with clips on the underside of the counter
The last item on the shower wall, the tub
existing valve stems, don’t panic.
and sealed with a bed of caulking or plumber’s
spout, can often be unscrewed by hand. If not,
Most major plumbing suppliers
putty between the sink lip and the counter. After
you can usually gain some leverage by inserting a
offer threaded valve extensions
disconnecting the pipes, unscrew the clips and, if rubberized plier’s handle into the spout opening.
to make the stems longer. that’s
necessary, break the caulking seal by running a
Tile to within 1⁄4 in. of the valve stems and
much cheaper than tearing out
putty knife between the sink lip and the counter.
pipe stubs, and caulk the gaps with silicone so
the walls to replace the valves.
If the new sink is smaller than the old one, you’ll
water can’t get behind the wall. Escutcheons will
need to reframe the opening in the counter.
cover the cut tiles.
Remove in-counter faucet assemblies, then
Build up electrical boxes so they’re flush with
tile within 1⁄4 in. of the holes, and caulk the spaces new tiled surfaces. After turning off electricity
with silicone or plumber’s putty. If your installa-
to the box—and using a voltage tester to make
tion will involve just thinset and tile, the old valve sure it’s off—remove the outlet faceplate,
stems should be long enough to reuse. But if
unscrew the device from the box, and screw in a
you’re building up the setting bed with backer
box extender. Run tiles to within 1⁄16 in. of the
board or mud, buy new faucet assemblies with
extender; the faceplate will cover tile cuts. Note:
longer valve stems.
All bathroom receptacles and all those within
Shower and tub hardware can be masked off
4 ft. of a kitchen sink must be GFCIs.
with plastic bags if you’re not tearing out the
Move appliances so the floor they’re sitting on
shower walls or building up setting beds, but do
can be tiled. Where those appliances are under-
remove chromework so it doesn’t get discolored
counter, anticipate the additional height of the
by mortar or adhesive.
new flooring and raise or alter countertops
tiling
461
accordingly so appliances can be returned to
their nooks.
Cut door bottoms so there’s about 1⁄4-in. clear-
zzzzzz extending electrical boxes
Old drywall
ance between the bottom and the highest point
1/4-in.
of the tiled floor or the threshold. Do this after
backer board
the tile and threshold are set because it’s difficult
to know beforehand exactly how thick the floor
Box extender will be.
P R O T I P
Choose a threshold that reconciles floor heights
don’t use drywall screws to
and materials on either side. For this, you’ll need
attach backer board. they’re not
to think through its installation, such as scribing
strong, screw heads can shear
and cutting it to the door jambs and the adhe-
off, and drywall screws invariably
sives or fasteners.
corrode in damp and wet applica-
1/16-in. gap
tions. use only corrosion-
resistant screws or nails. don’t
Instal ing Setting Beds
Thinset
use drywall joint tape either; it’s
This section addresses mainly the most common
Electrical
not up to the task.
Tile
setting beds and mentions only briefly those that
box
are less common or problematic. Backer-board
brands vary, so follow manufacturer-specific rec-
ommendations about waterproofing, connectors,
installation procedures, and so on.
A box extender is usual y a plastic sleeve
that screws to an existing electrical outlet
coMMon Setting bedS
box so that the box face is flush to a
Here you’ll find additional details on backer
new tiled surface.
board, mortar beds, SLCs, drywall, and concrete
slabs. Setting tile directly on plywood is not rec-
ommended, but it’s widely done, so that’s
addressed, too.
installing backer board. Backer boards are
cementitious backer units. They are strong, dura-
ble, and unaffected by moisture—so they are
superb setting beds for wet and dry installations.
However, because moisture will wick through
CBUs, install a waterproofing membrane first in
wet applications to protect wood substructures
from damage.
Wear a respirator and eye protection when
cutting and drilling backer-board panels, which
can be scored and snapped much like drywall
A handheld grinder with a diamond blade makes a faster, more reliable cut in backer board than a
utility knife, but it also produces more dust.
To install a backer-board setting bed over an existing
substrate, drive 2-in. galvanized roofing nails into the
framing. Alternately, use 2-in. corrosion-resistant screws.
462 chapter 16
expansion
Note how well self-leveling
JOinTS
compound levels itself when
accidentally dumped onto the
ground of a work site. Even its thin,
All tile substrates and setting beds need 1⁄4-in.-
tapered edge is strong. When used
wide expansion joints where they abut walls,
to level floors, its optimal thickness
fixtures, and cabinet bases. This keeps grout
is about 1 in.
joints from compressing and cracking when
materials expand. These joints are usually
caulked with a flexible sealant, such as silicone.
(many installers score both sides). Although a
installing the mortar bed. Mortar beds make a
utility knife can do the job, a dry-cutting dia-
superb substrate but are complicated to install.
mond blade in a handheld grinder leaves other
First, attach a curing membrane (a waterproofing
methods in the dust—literally. Wear a respirator
membrane beneath the mortar) over the framing
when using this grinder, as well as hearing and
or drywall, then add reinforcing wire mesh.
eye protection. To drill pipe holes, use a carbide-
Next, apply two or more parallel mortar columns,
tipped hole saw.
and place a wooden float strip atop each column.
For most backer-board installations, space
Checking frequently with a spirit level, tap the
galvanized roofing nails or corrosion-resistant
float strips into the mortar until the floor strips
screws every 6 in. to 8 in. Screws are more expen- are level or the wall strips are plumb. Then
sive and slower to install, but some tilesetters
fill between the strips: Dump mortar onto floors
swear by them; Rock-On® cementboard screws
between the strips or trowel it onto walls. Flatten
cut their own countersink so the heads will be
the mortar by placing a screed board across the
flush. Nail advocates argue that nails are less
float strips and drawing it side to side in a sawing
likely to crush panel edges and are easy to drive
motion. Dump excess mortar into a bucket as the
flush. To attach 1⁄2-in. backer-board panels directly screed board accumulates it.
to studs, use 11⁄4-in. screws or nails. If installing
Once the mortar bed is more or less flat,
panels over drywall or plywood substrates, use
remove the strips, and fill the float-strip voids
2-in. screws or nails.
with mortar. Then trowel out the irregularities.
Backer-board panels are available in a variety
To help the thinset coat adhere, lightly roughen it
of widths (32 in. to 48 in.), lengths (3 ft. to 10 ft.), by rubbing the surface with a wood float or a
and thicknesses (1⁄4 in., 5⁄16 in., 7⁄16 in., 1⁄2 in., and
sponge float. Allow the mortar to set about an
5⁄8 in.). Thinner panels are typically installed over hour before using a margin trowel to clean up
plywood or drywall. Use at least 1⁄2-in. backer
the mortar bed’s edges. Some veteran tilesetters
board if you’re attaching it to bare studs; other-
set tile immediately thereafter, but most mortals
wise, it will flex too much and crack the tile
should allow the mortar to cure for 24 hours
joints. For a floor rigid enough to tile, install
before tiling.
1⁄2-in. backer board over 3⁄4-in. tongue-and-groove
Mixing mortar in correct proportions is an
plywood, with j
oists spaced 16 in. on center. For
art. Floor mud, or deck mud, is dry and rather
all installations, leave a 1⁄8-in. gap between the
crumbly: 1 part portland cement, 5 parts sand,
backer-board panels. Cover those joints with
and 1 part water. However, once screeded, com-
2-in.-wide, self-adhering fiberglass mesh tape
pacted, and well cured, deck mud can support
before covering the tape with thinset adhesive—
great loads. Wall mud is wetter and more like
the same material used to set the tiles.
plaster because it must be spread onto vertical
Feather out the thinset as flat as possible, but
surfaces; it contains lime to improve its adhesion.
it doesn’t have to be perfect because the joints
Wall mud’s proportions are 1 part portland
will be covered by adhesive and tile. Finally, leave cement, 4 parts sand, 3⁄4 part lime, and 1+ parts
a 1⁄4-in. expansion gap where the panels abut the
water; use enough water so the mud trowels on
base of walls, tubs, and plumbing fixtures; you’ll
easily. Add water slowly because mud won’t stick
fill those gaps later with flexible sealant. Keep the if it’s too wet.
bottom edge of backer board 1⁄4 in. above the tub
Applying leveling compound. SLCs can level
so water doesn’t wick into panels; caulk the gap
isolated low spots or even whole floors.
later with silicone.
Application requires few skills beyond opening
50-lb. sacks of SLC powder, mixing the powder
tiling
463
curing compounds in concrete slabs—that might
prevent a good bond.
Before pouring, install a waterproof mem-
brane and reinforcing mesh, which is usually
wire, although a self-furring plastic lath called
Mapelath™ shows promise. One essential prep
detail: Completely seal and dam off the section of
floor you’re leveling, or the free-flowing SLC mix
will disappear down the smallest hole and form a
heavy mortar pad where you least want one. Pay
close attention to board joints, baseboards, and
the like; caulk or seal joints with duct tape, pack
them with fiberglass insulation—whatever it
takes to contain the liquid until it hardens. SLCs
are expensive but, in most cases, less expensive
than floating a mortar bed. As important, they’re
great setting beds.
Preparing masonry surfaces. Concrete walls,
slabs, and block are good setting beds as long as
they’ve cured for at least a month and as long as
they’re clean (no chemical residues), dry, free
Renovation 4th Edition Page 108
