Ceramic Tile Underlayments-The Basics

Ceramic tile material is rigid and relatively brittle, so a sturdy base is the most critical part of installing this type of tile. Unless you want to see cracked tiles, loose tiles, or loose grout, you need to select the proper underlayMent. UnderlayMent being what the construction trade calls the layer that goes between your wood subfloor and your tiles.

Ceramic Tile Underlayments-The Basics

Ceramic Tile Underlayments-The Basics

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Ceramic Tile Underlayments-The Basics

Ceramic Tile Underlayments-The Basics

You have several alternate ways to accomplish the strong underlayMent required for ceramic tile installation.

Plywood-just a single layer of plywood isn't rigid enough to stop floor deflection. It needs to be covered over with an additional layer of exterior-grade plywood to achieve a total thickness of at least 1 1/8 inch. You can either (A) Cover the plywood with a cement backer board (more on these below) or (B)Cover the existing plywood with a second layer of exterior grade plywood. Under either of these, a thin-set mortar is applied to eliminate Air gaps. Additionally, in bathrooms, it's recommended to lay a "shower pan" over your wood subfloor. This refers to thin rubberized materials that protect the tile from floor expansion and contraction due to moisture, temperature and humidity.

Cement Backer Board-These are "prefabricated", lightweight concrete sheets used to cover wood subfloors. It has a dense Portland concrete core and fiberglass surfaces both sides and is able to withstand prolonged exposure to moisture. Brand names include DUROCK, UTILICRETE, WONDERBOARD and GLASCRETE. Joints of the backer board sheets should be sTAGgered such that they don't fall directlyover the wood subfloor joints.

Mortar Bed-Mud beds, or mortar beds, are used by professional tile contractors mostly. They're composed of a layer of thick roofing felt, then wire mesh, followed by a layer of mortar. The reason it is used mostly by the specialists is that it takes a high level of skill and practice to ensure the mortar bed produces a sufficiently level surface. The other reason is that it is the best foundation possible for a ceramic tile floor. Okay, but why? Because the mortar bed has a built-in reinforcement against floor deflections in the form of the wire mesh. Translation-less cracked tiles and loose grout, and longer-life flooring.

Ceramic Tile Underlayments-The Basics

Homebuilding: Installing Sill Plates

When building a house, installing the sill plates correctly
will determine how straight and square the finished product
will be.

Homebuilding: Installing Sill Plates

Homebuilding: Installing Sill Plates

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Homebuilding: Installing Sill Plates

Homebuilding: Installing Sill Plates

Hopefully the concrete contractor did his Job and left you
with a reasonably straight and square foundation. A good
concrete contractor can make a Job of framing contractors
building a house a piece of cake. Even if the foundation is
slightly out of square, good framing contractor can adjust
his sill plates and correct the problem.

When laying out the sill plates, snap chalk lines on the
biggest square of the foundation. This will usually be the
main part of the house. After snapping the front or back and
one side, check for square. This is easily done by using
the 3-4-5method. Measuring 3 ' from the corner on the side,
and 4 ' from the corner on the front or back. Make a pencil
mark on the chalk line at these diMensions. Measure the
distance between these two marks on the diagonal and if
perfectly square will equal 5. If it is not square, adjust
the shortest of these two lines so that your measureMent
equals 5 '.

Once squared these lines can be used as a reference point to
keep parallel square and other sections of the houses
foundation, like a garage or sunroom. By using the biggest
square portion of the house, your work will be more
accurate.

After your chalklines are all snapped, your ready to lay the
sill sealer and sill plates. The sill sealer is put on top
of the foundation wallfirst. This material comes in two
forms. One is very similar to fiberglass wall insulation
except thinner and with the same kraft paper backing. The
other is a 1/4 "foam similar to laminate flooring
underlayMent. Both materials come in widths to accommodate
2 x 4 and 2 x 6 sill plates. I prefer the foam sill sealer for
its ease to work with and what I feel will keep drafts and
moisture from penetrating under the sill plate better. Both
sealers are installed butting up to the chalk line to the
inside of the foundation wall. Both are pushed down over
the anchor bolts till it pops through the sealer.

The exterior finish determines the placeMent of sill plates
on the foundation wall. If the exterior finish is siding,
the sill plates will finish flush with the outside of the
foundation wall. In this case I like to measure in the width
of my sill plate, 3 1/2 "for a 2 x 4 and 5 1/2" for a socket. If
the exterior finish is brick, the sill plate will be 4 1/2 "
from the outside edge of the foundation wall.

Holes must be drilled in the plates to install them over the
anchor bolts. These 2 x plates are usually required to be
treated lumber to resist rot. To locate the bolt hole in the
2 x, put the plate up against the anchor bolts. Using a speed
square or a combination square, put the square on the edge
of the 2 x and against the anchor bolt. Hold your pencil
against the squares with the lead edge 1/4 "away from the
blade of the square and draw aline. This will give you the
center of the 1/2 "anchor bolt along the length of the 2 x
plate. to get the center off the edge of the plate, measure
from the chalkline to the center of the bolt. This will give
you the location to drill the holes in the plate. Drill to
3/4 "hole in the plate. This allows some wiggle room to drop
the plate over the anchor bolts which are not always
straight up and down.

Once the holes are drilled in the plate, bolt it down with a
hex nut and washer. Continue the process by butting the next
plate to the one just put down and locate the next set of
holes, putting the sill sealer down ahead of the plates. Toe
all joints where the nail plates butt one another.

This is an important step whenbuilding a new home. By
installing the sill plates straight and square, it gives a
solid reference to follow when framing the rest of the
house.

Mike Merisko (c) www.sawkerfs.com

Homebuilding: Installing Sill Plates