The Slate Floor Tile Project

For nearly nine months, stacks of slate tiles had been guilt-tripping me.  They’ve sat in a corner of the dining room (a.k.a. the dumping room) eagerly awaiting their ultimate destination.  Sometimes weeks would go by before I would check in on them; they never moved or made any self-installation attempts.  I was busy with other projects.  The only reason that the slate tile was purchased when it was, was the sale price.

When we purchased our current home, the main floor came with a selection of foul flooring media.  The living room and dining room came adorned in a faded powder-blue, and dog-urine-stain infused carpeting.  The entryways and kitchen floors were covered with a lovely stark-white, perpetually unclean-able ceramic tile (we paid nothing extra for the loose and cracking grout).  The family room has the softest, highest quality carpeting I have ever tread upon; what it makes up in quality, it lacks in both style and taste.  I’m certain this patterned carpet was the very same used in the Hall of President’s foyer at Disney World (just more dizzying).  So, on the master-plan stored and studied in my head, the existing flooring, as lovely as it is, will have to go.

I would like to remove all of the existing flooring as soon as possible.  The plywood sub-floor alone, may improve the overall flooring aesthetics of my home.  With the exception of the home’s entryways, the plan is to replace all of the first floor flooring with wood (more likely to be bamboo flooring).  The entryways, one of which is the subject of this post, will be replaced with slate tile.

One Saturday morning, my wife inquired about the piles of tiles in the dining room.  I didn’t reply.  Perhaps it was the accumulated guilt, or maybe it was the rare obligation-free weekend, but something in side of me took over and led me to the garage.  I picked up the 10lb sledgehammer that was resting in the corner and went back into the house.  My wife watched me curiously as I stood there holding the sledgehammer.  Before she could ask what I was up to, I proceeded to drop the sledgehammer on the entryway floor.  The early ’90s china-white ceramic tile didn’t have chance.  The slate tile project had begun.

Removing the Existing Ceramic Tile

Prior to removing the existing tile, the trim baseboards had to be removed.  My wife joined in on this exciting task.  Slowly and carefully, she used a pry-bar, screwdriver, and hammer to pry the trim boards away from the wall.  It’s far easier to reuse the existing trim than having to cut and finish all new trim later.  The more care that can be used during this step, the better.  Loosening the boards carefully will prevent them from cracking, chipping, and denting.  Once removed, I recommend numbering each trim piece and the wall where they should be placed.  We used a permanent marker to do so; be sure to label the wall low enough so that the trim covers your writing once replaced.

Having had to remove ceramic tile in the past, I had readied myself for the arduous task of prying the tile up, broken-bit by broken-bit.  However, this time the tiles nearly removed themselves.  Using nothing but a standard putty knife, I was able to pop up complete or nearly-complete tiles with very little effort.  I don’t know if it was the age of the floor, or that the wrong mastic had been used, but I was able to remove the ceramic tile from the entire entryway floor, coat closet, and powder room in less than 30 minutes.  With some more follow-up concentrated scrapping in areas that needed it, the existing plywood sub-floor was nearly bare.

I had been worried that I would have to remove and replace the plywood sub-floor prior to installing the slate, but it wasn’t going to be necessary to do so.  The existing plywood was in good shape and after some scrubbing with soap and water, it was clean enough that the new mastic and slate tile would adhere to it.  Woo-hoo!  Maybe this wasn’t going to be the nightmare project that I had been dreading for so long.

Slate Tiles vs Ceramic Tiles

Though there are slate-looking versions of ceramic tile, my wife and I couldn’t find anything that came close to the beauty of natural slate.  That is the only reason to choose natural slate over ceramic tile.  Unlike slate tile, ceramic tiles are:

• Uniform in Size & Depth – The size and depth of slate tiles often varies considerably from tile to tile.  Also, individual tiles may vary in depth from side to side.
•  Stronger, More Durable – Slate tile can be very brittle, and can chip, crack, and flake very easily (especially prior to installation).  Ceramic tile can take some abuse that slate will not handle.
• Water Resistant – Water will not penetrate glazed ceramic tile.  Slate tile is stone, and stone is porous.  As much as I like slate, I would never use slate tile in a bathroom that has a shower or tub.
•  Maintenance Free –  Slate must be maintained and sealed to resist moisture.  Impregnator/sealer will have to be used to protect the slate from wear and exposure to moisture.

The four points above seem to be pro-ceramic, but in this case, slate still wins due to its appearance.  Here’s why:

• Unique, Natural Beauty – You will not find a ceramic tile that can compete with the beauty that nature has created over millennia.  Slate tiles may have inclusions, colors, and texture variations that you cannot get in manufactured ceramic tile.  Even the variations in depth and size add to the aesthetic appeal of slate.  In our case we wanted the rustic, natural look and feel that we could only get from slate tile.  The slate floor is art.

Installing Slate Tile

Having previously installed ceramic tile, I can undoubtedly state that slate is markedly more difficult to work with.  You will need a decent wet-saw to cut the tiles.  Don’t even think about using a tile scorer or tile nippers; the slate tile will crack or crumble.  Even using a wet saw to cut the slate can be a challenge.  Tiles with weak spots or unseen hairline cracks will not take the stress of cutting.  Be sure to include at least 20% waste in your material estimate; you’ll likely need it.  Also, when you are measuring and marking the tiles for cuts, use a chalk pen or pencil.  Don’t make the mistake of using a permanent marker or pen; they will not be easy to remove from the slate later.

It’s always best to dry-fit (temporarily place) the tile prior to doing any permanent tile placement.  You may have to try a few different layouts to find the best tile placement.  For my project, I found that having as many full tiles in the center portion of the entryway, passing straight forward through the powder-room door, looked the best.  This required that I cut the majority of the slate tiles along the perimeter of the entryway and powder-room floors.

If your new slate tiles do not fit underneath the base of the existing door frame trim, you will need cut the trim to allow enough clearance to slide the tile in.  Don’t make the mistake of cutting the door frame base with a standard saw, you won’t be able make a clean, straight cut.  I highly-recommend getting one of these flexible saws to do the job:  Irwin Pull-Saw.  Butt one of your slate tiles up against the door frame trim, gently press the flexible pull-saw on top of the tile and use it to guide the frame trim cut.

Once you’ve cut and dry-fit all the slate tiles and you’re satisfied with the placement, it’s go-time.  Use a chalk-line to mark the placement of the first row of tile; this line is your guide to keeping all of the subsequent tiles straight.  For permanent tile placement, be sure to choose the right tile mastic or adhesive for your project.  I used an acrylic-based tile/stone adhesive (rather than a standard ceramic tile mastic) because there was some flex in the sub-floor that the slate was being installed on.  You can likely use a standard tile mastic if you are installing over concrete.  If you’re not certain which to use, check with a flooring pro at any of the big-box home improvement stores; they’ll know which will work best for your situation.

Use a notched tile trowel to apply the tile adhesive to the sub-floor in an even, semi-circular pattern.  It’s best to limit the amount of adhesive applied to an area that can be covered by 2-3 slate tiles.  Once the adhesive has been applied, try to place the tile evenly onto the adhesive and press gently to set the tile in place.  You will continue this process, ad nauseum, until all of the slate is placed.  You will likely have some tight spots along the walls and in corners that will require you to use the front-edge of the trowel to apply the mastic.  Even coverage is the key, don’t worry about how neat the adhesive looks.

Placing tile spacers between the tiles as you install them, will help to keep all of your tiles straight, and grout lines even.  We liked the look of the 1/4″ grout lines, so for our slate project we used 1/4″ spacers.  The spacers come in various sizes; use whichever you prefer for your project.

Slate Tile Grout

Once the tile was installed, we stayed off the floor for 48 hours to allow the tile adhesive to set.  It was grouting time.  We chose a grout color that matched the darkest common colors in the our slate tiles.  I’d describe that color as charcoal-gray.  Using a 5-gallon bucket purchased from the local home improvement store, we mixed the powdered grout mix with water as directed.  The ready-consistency will be firm but pliable; you certainly don’t want the grout too thin and runny.  Add water to the mix slowly until the grout is a consistency that you can work with.

You’ll need a rubber grout float and grout sponge to apply the grout.  I’m sure there are many methods to apply the grout, but I find it easiest to apply a baseball-size glop of grout to the corner where four slate tiles meet.  Simply drop the glop (very poetic of me) of grout and begin pressing it firmly between the tiles.  Be sure to press firmly enough so that the grout completely fills an accessible voids and spaces between the slate tiles.    Don’t grout yourself into a corner; you’ll want to start in an interior area of the floor and work your way outwards towards an area you can exit.  Once the grout is in place, you’ll want to stay off it for the time indicated in the grout instructions (usually 24-48 hours).

Don’t be overly concerned with the mess at this point, but keep in mind that the less grout on the surface of the tile now, means less grout to clean off later.  I keep an old damp rag to rough-clean the tile surface as I go.  Try to keep the grout lines consistent, smooth, and even.   Once the grout has dried, you won’t have many options to make corrections.

Grout Cleanup

Once the grout was set, it was time to clean up.  Usually, cleaning up is not something to look forward to, but this was different.  The haze of dried grout had dulled the beauty of the slate tiles and I was excited to get them looking good again.  In a clean bucket, I combined about one gallon of warm water with a tablespoon of Dawn dish soap.  It took three rounds of scrubbing the floor to completely clean any residual grout from the slate’s surface.  You’ll want to be sure the surface is completely clean prior to sealing the slate.

Sealing the Slate Tile

Be sure that there is no standing water on the surface of the slate prior to applying the sealer.  The slate can be slightly damp or dry when applying the sealer.  Be sure to verify that the sealing product you choose allows for the same application conditions.

The sealer is a very thin, watery liquid that can be easily applied with a decent paint brush, roller, or towel.  Apply the slate sealer evenly to a few tiles at a time.  Allow the sealer to set for a minute or two and follow-up by wiping the sealed tiles off with a clean white towel; this will remove any residual/excess sealer from the tile’s surface.  Once all tiles and grout surfaces have been sealed, allow the sealer to fully cure for 24-72 hours (curing time will depend on the type of sealer you end up using).  In my case I stayed off the floors for 48-hours.

Finishing Up & Project Cost

Once the slate tiles were installed and sealed, I moved on to reinstalling the baseboard trim molding (which was easy to do since the trim was labeled).  The wood trim, combined with the slate floor, make the space warmer and more natural-looking.  I’m very happy with the dramatic aesthetic improvement to the entryway and powder room.  The total cost for the slate tiles, adhesive, grout, and sealer was just under $270.