Before
This is a story about Cork Tile that I installed solo in my client’s condominium home in the ever popular Arcadia neighborhood of Phoenix, Arizona. The photo gallery directly below are of the three areas (Master Bedroom, Back Bedroom and Living Room) as I saw them upon my initial consultation with the client. Photo captions describe what a few of my considerations were at the time. These are some Before photos.
1. Transitions
There will be new porcelain tile in this master bathroom. What I’d like to achieve is a flush transition between the cork and tile.
2. Exterior Doors
Checking that the arcadia door doesn’t allow water to pass into the room will be something I pay particular attention.
3. Slump Block
Exterior walls on this project are raw or painted, irregular concrete slump block with no base molding. Finishing the cork cleanly to the block will be challenging.
4. Closets
Closets are a pain-in-the-neck, they also have slump block walls to deal with. Bifold doors are often troublesome to remove and reinstall.
5. Kitchen Tile
Even though I won’t be installing the new tile in the Kitchen and Dining room, I look for hollow and cracked tile that can indicate problems with the subfloor.
6. Transition & Windows
The foyer will receive new porcelain tile and the transition to the cork tile will need to be considered. One wall is all glass and the intense sunlight will be an environmental aspect to consider.
Product
Inspection
The first order of business is to inspect the cork tile for quantity, quality, style and color as I deliver the customer’s product. This is part of the due diligence I perform before starting the subfloor preparation work. I like to get in front of any potential problems to avoid surprises. Check out the gallery for more wisdom.
Palletized Cork Flooring
This material came from Portugal to a Canadian distributor and then shipped to the customer in Arizona. It has traveled quite a bit and it probably has jet lag and needs to relax a bit. One of the reasons I use an enclosed truck for delivery is to keep the material out of the direct sun.
Stacked Material
The cork tile and sundries are staged in a corner of the last room who’s subfloor I plan to prepare. I redistribute the material to the appropriate place after I ready the other areas.
Damaged Cartons
It’s inevitable that there will be shipping damage. I always verify quantity and quality and take into account damaged material and whether or not I may be able to utilize some portion of it.
Agglomerated Cork Tiles
The product is from durodesign out of Canada. It’s made in Portugal and is about 3/8″ thick by 12″ X 24″. Tiles are packaged and stacked on edge and should be kept that way until installation.
Two Component Water-based Urethane
A five gallon container of MP765 the recommended urethane finish coating for cork tile. This product is mixed with a part B hardener and applied in four coats.
Part B of the Urethane Finish
The MSDS (material safety data sheet) is for the enclosed urethane varnish, Part B.
Wagner Moisture Meter for Wood Flooring
As the product acclimates to the environment it will reside for its entire lifetime, I monitor it’s moisture content for any unusual changes.
Thermometer & Hygrometer
I’ve had a couple of these digital Thermo-Hygro for many years. They’re from Radio Shack, you might guess how old they are since the electronics store has been out of business since 2015. I place the device in a centrally located area at the start of a project to monitor and document the temperature and relative humidity of the environment.
MVE
& pH
Testing
Anytime I plan to bond floor covering to a subfloor (especially a concrete subfloor, as in this case) I mechanically abrade (clean) the surface. Before I set out to complete the task I strategically clean a number of four to nine square foot sections throughout the project so I may confidently perform Calcium Chloride moisture vapor emission (MVE) and pH tests. MVE testing is a manufacturer requirement to maintain their product warranties, but for the other reasons why you should consider this, check out this page- Concrete Moisture Testing.
Tramex Concrete Moisture Meter
The CME 4 helps me determine where the concrete subfloor might have pockets of higher MVE relative to other parts of the subfloor. I may consider setting the MVE tests in these areas.
MVE Test Set
Once the MVE test is set it needs to remain intact for 60-72 hours (3 days). I use this time to continue to prepare the concrete subfloor. Once I get the test results I’ll determine if moisture mitigation is necessary or optional.
Sealed MVE Testing Dome
The MVE test dome has a sealant that bonds well to clean concrete. If the concrete surface is dusty or contaminated the seal may leak invalidating the test.
Weighing the Sample
If you don’t weigh and do your own calculations you have to wait for your test results from the third party vendor to proceed with the installation. At this point if I determine the slab is in an unacceptable condition in regard to MVE I will require a moisture mitigation solution. Otherwise, a concrete surface sealer is what I consider a cheap insurance option that I offer to my clients.
Ready to Ship
Taylor Tools provides envelopes to ship your samples to their Denver, CO facility. There they do their own weighing and calculations and should provide the third party written documentation as part of the cost of the test kit. If a moisture problem arises in the future the documentation will help in knowing that at the time of testing the subfloor was in an acceptable condition to install the new floor covering.
pH Test Using Taylor Tools MVE Kit
The Taylor Tools MVE test kit comes with distilled water and a couple of litmus test strips and a comparison results chart.
pH Testing Results
Looks like the pH readings of this concrete subfloor are in the 4.5 to 6.5 range.
Subfloor
Preparation
When I plan to bond floor covering to a subfloor I mechanically abrade the surface. Cleaning is the first of the four-step subfloor preparation process: Clean, Dry, Flat & Smooth (CDFS) are the four critical subfloor preparation aspects relevant to the long term success of a floor covering installation. It’s vitally important to remove all surface contaminants and bond breakers. Even the often overlooked invisible, concrete curing compounds, commonly used in the desert heat.
Opening the pores of the concrete in order to create a favorable surface profile and achieve superior adhesion is crucial. The abrading process helps me get up close and personal as I move the hand grinder along the subfloor; as a direct result I not only clean, but smooth the floor at the same time. At that point I can then make an initial, confident flatness determination through sight and feel.
At this stage of the project I determine and/or correct not only CDFS but also determine and correct subfloor integrity, transition heights and undercut any vertical abutments that can be, so that I’m able to fit the floor underneath.
Night and Day
There’s a highly discernible difference between a cleaned concrete subfloor and a contaminated one. Don’t be fooled by pretenders who just want to use a razor hand scraper; this is what clean should look like and high powered mechanical abrasion is the only way I know of to achieve the required level of clean.
HEPA Vacuum
The Vacuum is a Pulse-Bac 1000 and sports three HEPA filters that does a great job at keeping the jobsite clean of dust. It’s not a 100% dust free operation but the conditions it maintains are satisfactory for occupied residential work.
A Clean Subfloor
Once the subfloor in grinded (or ground) clean I move on to the next phase of subfloor preparation – flattening.
Gauging Subfloor Flatness
I use a long aluminium screed or straight edge to calculate and give me an overall picture of where and how much the concrete subfloor needs to be flattened. Understand we want to achieve a flatness tolerance here, not necessarily level.
Concrete Subfloor Flattening
I use a four foot level and my own gauging system to determine where and how much material to remove. The mechanical grinding is done in a number of passes using a Hilti DG-150 diamond grinder with attached HEPA vacuum. Removing the highest high spots is the first flattening phase.
My Gauging System
The lines guide me when removing material to flatten the subfloor. The position of the lines tell me where to concentrate my efforts. The length of the pencil lines tell me how wide a swath to make and the number of lines or intensity tell me how much to cut or how much downward pressure to apply to the grinder. The number 8 refers to 1/8″ of material needs to be removed at that point. No numbers mean approximately 1/16″ should be removed in this pass.
A Bit at a Time
As concrete material is removed it will often expose the extent of the damage to the subfloor. Cracks tend to appear wider the further down you go. This is merely an eighth of an inch of material being removed and has revealed a concrete subfloor integrity condition that will need to be addressed.
Wall Strap
This is a close-up view of the wall strap that needed to be buried in the subfloor. I’ve made the determination that the posts are most likely hollow because the electrical outlet would require a box to safely reside. This prompted the idea that the sills may be of the same materials and that they would cooperate if I tried to undercut them.
Window Wall
The two straps that attach the posts of the window wall were installed on top of the subfloor and hidden by carpet and cushion. That arrangement will not work for our cork tile so the strap was removed, and a channel was ground into the concrete. The strap was reattached using epoxy adhesive and expandable aluminum pins.
Undercutting The Sill
Beside the undercutting of the concrete block walls, along with wood door jambs and casings, I also undercut the wood plate that the glass sits atop in the living area. The depth of the cut is only about a half-inch, by the thickness of the flooring, plus any applied subfloor toppings. Silicone is then applied in the channel as an added measure of protection from water intrusion. The cork tile sample is used to determine the integrity of the channel.
Wall Strap
Once the window-wall strap has been reset and reattached, I smooth it over with floor patch.
Carpet Hides Subfloor Sins
The area along these subfloor cracks were heaved, created a hump that was higher than the rest of the floor and needed to be ground flat. Notice the exposed aggregate where material was removed in comparison to the surrounding float finish. I was concerned about the integrity of the concrete in this area, that caused me to decide to install an epoxy adhesive to stabilize the crack.
Gun Grade Epoxy
I inject an epoxy adhesive into the crack between the slabs in an attempt to bond the two or more sections together. The idea being to create a homogenous and stable subfloor to bond the new cork tiles.
Epoxy Adhesive Filler
Applying an epoxy adhesive in the subfloor cracks after it has been flattened, aids in stabilizing the subfloor. The idea is to keep the crack from expanding both horizontally and vertically after the finished flooring is installed.
Stabilizing the Subfloor
I will often apply an epoxy adhesive as an initial filler for concrete subfloor cracks to stabilize and mitigate future movement that may affect the bonded, finished floor covering.
Undercutting
I need to cut a channel at the bottom of the slump block exterior walls to receive the cork tile. This special undercut saw from Crain Tools is equipped with a diamond cutting blade and vacuum.
Undercutting Concrete Block Walls
Undercutting concrete slump block walls is a labor intensive task but makes for an appealing finish where the vertical and horizontal finishes meet. I make one cut about a half-inch deep to accommodate the cork tile thickness. I then chip away the wall material between the cut and the subfloor.
Shim Thickness
The top of the porcelain tile may have been installed flat but the subfloor it was installed on was not flat. Varied lengths of wood shims account for various gauge thicknesses so that the ramp will be the appropriate height when complete.
Hot Melt Construction Adhesive
A specially formulated hot melt adhesive is used to install the wood shim gauges to the cleaned concrete subfloor. A cork tile sample is used to determine the thickness of the shims. The goal is a smooth, flush transition between floor types.
Patch Mixing Station
This is where and how I set-up for mixing three different types of cement patching compounds; using Mapei products, Primer T, Nova Plan 2 Plus – SLC (self-leveling cement), Planipatch (deeper fills) and Planiprep SC (skim coat).
Ramping
For the top of the cork tile in the living area to be flush with the top of the porcelain tile in the dining area, I use a technique called ramping. Multiple layers of concrete patching compound is utilized to create an undetectable slope underfoot.
Height Difference
This is where the cork tile will transition to the master bathroom porcelain tile. The difference between the height of the finished bathroom floor in 5/8″ and the tile is 3/8″. The 1/4″ difference will be made up by installing a gradual sloping ramp. Once the subfloor is clean the primer is applied.
Priming the Subfloor
SLC primer is a critical part of the subfloor preparation system. Products that are being bonded or layered together must be compatible to avoid failure. The primer will enhance the adhesion between layers.
Shims & Priming
I attach the wood shims to the concrete subfloor as a thickness gauge for the creation of the ramp. These will remain buried by the patching compound and the entire area has been primed to receive the first coat of self-leveling cement (SLC).
Ramping Complete
The subfloor has been raised slightly (ramped) at the living area transition to the kitchen. This is the finished ramp ready for concrete moisture vapor sealer (retarder).
Concrete Sealer Application
Image showing the Mapei Planiseal MSP brush applied on the living room subfloor where the cork tile will create a flush transition to the porcelain tile.
Cutting-in
Much like painting a wall, the concrete subfloor sealer, Mapei PLANISEAL MSP, is first brush applied around the perimeter of the back bedroom floor.
Installing Sealer
Concrete moisture vapor sealer (Mapei Planiseal MSP) being applied around the perimeter of the master bedroom subfloor.
Roller Applied
The bulk of the Mapei Planiseal MSP is applied with a paint roller in two coats for maximum protection against moisture vapor emissions.
Living Area Protected
The living room subfloor has been sealed and is ready for the final smoothing phase.
Mapei PLANISEAL MSP
Back bedroom sealed and ready for the final smoothing stage.
Master Bedroom Sealed
Master bedroom sealed and ready for the final smoothing phase. Two to three coats of Mapei Planiprep will be hand troweled on top of the concrete sealer.
Ready to Cork in the living room area.
A photo of the prepared subfloor in the living room area. We’re ready to drop our layout lines and spread the adhesive.
Final Skim Coat
This is the final skim coat (it took three coats) of hand troweled cementitious patching compound. Once it is dried I will scrape or sand any ridges to create a glass-like smoothness.
Ready to Cork
A photo of the prepared subfloor in the master bedroom. I’m ready to drop the layout lines and spread the adhesive.
Ready to Cork
A photo of the prepared subfloor in the back bedroom, off the kitchen & hall. I’m ready to drop the layout lines and spread the adhesive.
Cork Tile
Installation
In this chapter I touch on layout lines, application of the adhesive, setting the tile, finishing to obstructions and transitions.
Layout Lines
There are at least three layout lines here. The first line would be a lengthwise control line. In this case the control line would be the line that is most parallel to the exterior and interior walls. Parallel to the control line would be the start line and perpendicular to that would be the line that creates the start corner. Another perpendicular line is to offset the second course of cork tile a distance of half a tile (12″) from the first course.
Contact Adhesive
The back of this durodesign cork tile is precoated at the factory with the contact adhesive. To install, the subfloor is coated with the same type adhesive. Once the adhesive is dry the tile will bond on contact with minimal pressure. Repositioning is not possible. Notice that the adhesive is translucent allowing the layout lines to be discernible. I use ink to make the lines as opposed to chalk so that they will not be washed away when the adhesive is applied.
On the Mark
The first cork tile is set in the back bedroom. It’s critical that the layout lines are square and the tile itself is square and the tile is set exactly along those two lines.
Stair Step
The cork tile installation proceeds in a stair step pattern. This technique keeps gapping at a minimum.
Pick Two, Three or Four
Installation proceeding into the closet. It’s a good idea to pick tile from multiple cases in an attempt to randomize the shading throughout the floor.
Undercutting is the Bomb!
Undercutting concrete walls are a lot of work, but the juice is definitely worth the squeeze.
Starting Line(s)
Where to set the first tile? That could very well make or break the whole installation. The factors that go into that determination are numerous.
Let’s Roll
A final check on how the cork tile will transition to the porcelain tile at the entry foyer. Notice the steel roller at the ready and the stack or doors padded with furniture blankets.
Window Coverings
The intense sunlight does not help. I needed to cover the windows here with paper to avoid any problems that the magnifying glass may create.
Walking the Line
Whether you straddle one side of the layout line or the other with the first course, or even walk the line, does not matter as long as you are consistent. Best case scenario that I have found is that the line is initially left exposed. A number of factors may make resquaring necessary.
What Happened?
Contrary to popular belief, every cork tile is not straight, square or the same dimensions. There’s only a millimeter of difference in width between the two cork tiles that are focused on, but if corrective measures are not taken early on it may lead to chaos.
Monkey in the Middle
The start line in the living area is more or less in the middle of the room. One side of the room is installed then the other. From the middle to the ends.
Get on the Floor
One the tile is set it may initially receive light traffic for the first day or so. This is the area off the living room, I believe the client called it the office. This is where the subfloor needed quite a bit of attention, and it paid off.
Expansion Space
Realistically how much expansion space is required between the cork tile and any fixed obstruction. Aesthetics need to be considered in addition to performance. I believe I have found a happy median with various flooring products. In this instance the expansion gap is a consistent one-eighth inch. It will be filled with a styrofoam backer rod and a color matched silicone grout caulk. This will allow for some movement between the building materials and look pretty and be functional at the same time.
More Painting
The contact adhesive is applied in much the same manner as the concrete sealer. The perimeter of the subfloor is brushed on and the remainder, or the field is rolled on with a 3/8″ nappy paint roller. More on layout lines later.
Start Here
Placement of the first tile is critical. No twisting and no skewing allowed. It’s not as easy as I make it look.
Stair Step
Working away from the entry into the master bedroom using a stair step installation technique.
Tools to Use
Working away from the entry into the master bedroom using a stair step installation technique. I’m using a Bullet Tools brand floor cutter and a steel, hand seam roller.
More Concrete Block
If the floor and wall preparation is done cleanly and with care the finished product will likely be exceptional. The expansion gap at the arcadia door sill will be filled with a styrofoam backer rod and a color matched silicone grout caulk.
Recessed Mortar
One of the challenges of finishing to irregular surface vertical obstructions is making sure the edge of the deepest or most recessed parts of the wall will cover the edge of the cork tile. What we’re aiming for here is coverage continuity, otherwise known as – no gaps.
Cork & Concrete
The client was ecstatic about how well the cork tile finished to the exterior concrete block walls.
Transition Focus
Image shows a focus on the transition between the cork tile in the master bedroom and the porcelain tile in the adjoining bathroom. The expansion gap here is about 1/8″ and will be filled with a styrofoam backer-rod and a silicone, color matched grout caulk.
Cork Tile in the Master Bedroom
A view of the cork tile floor in the master bedroom, standing in the back corner looking toward the entry.
Flooring Transition
Here I’m protecting adjacent floor covering so that I can get right to the edge with the urethane finish without worrying about having to clean it off the porcelain tile, door jambs and casings.
Finish
Coating
The following photos in this chapter show the installed cork tile floor in various stages of coating. They are a bit redundant but the idea being, a wet urethane finish looks very different after it has dried. A client once said to me, “only a fool judges work before it is completed”. I don’t believe that to always be the case but it probably is in this instance.
Home Made Filler
It’s inevitable that a slight unavoidable gap might need to be filled between cork tiles. Filler material may be made from grated cork granules, stain and adhesive.
Caution Wet Tile
This is a freshly coated floor in the back bedroom.
Caution Wet Floor
Wet finish on the back bedroom cork floor. This is a fast drying water-based finish and dries particularly quickly in the dry desert environment.
Half Dry
Partially dry finish coating in the back bedroom.
View From the Kitchen
Still wet finish looking into the back bedroom from the kitchen.
A lot of back bedroom pics?
These pictures are about as much fun as like watching paint dry. That’s often how one feels when waiting to apply multiple coats of finish in one day.
My Goodness!
How many back bedroom, watching finish pics dry area there?
The last one?
Yeah, this is the last back bedroom pic. At least this one is more indicative of how the satin, urethane finish will appear when fully dry and cured.
The last one, really.
This photo of the back bedroom cork tile floor shows an almost dry satin finish.
The Living Area
The lighting here is harsh but check out the grout line at the bottom of the pic between the two different floor coverings.
Another Angle
The cement block wall is very porous, I felt it would stain if I accidentally got finish on it, hence the blue tape.
More of the Living Room
The perspective here is from the entry foyer. Looks as if this coat is partially dry.
A Little Closer View
Just a lot of photos of drying paint.
Almost Dry
Getting closer to the final product in the living area.
Last living Area Pic
Not much to see here, move on.
Last LR Photo
Unfortunately the harsh lighting does not do the floor justice.
New Perspective
Wet finish on the living room cork tile floor, with the view from the entry foyer.
No Fan Please
This is wet finish on the cork floor in the master bedroom. I don’t want dust landing in the wet finish so I try to keep the air as till as possible.
More Wet Finish
Master bedroom again here.
Wet & Dry
Master bedroom somewhere between coats.
After
Here are a few photos of the completed areas. Using natural floor covering products means that the floor is unique unto itself. Click here to read some interesting facts about cork flooring.
Back Bedroom
This is about as dry as I will see this cork tile floor as my tasks are complete. It looks dry but the finish has yet to cure. Once it does the customer will hang the baseboard molding.
Master Bedroom
I try to pay particular attention to keep the shading random but occasionally a couple of similarly shaded cork tiles will wind up next to each other. It’s the nature of the beast, but the camera also sees things that the naked eye does not and vice versa.
Living Room
Unfortunately, I never got to see the house after the new wall and window coverings, furniture or area rugs. But this floor is now over four years old and after initial rave reviews the client has never contacted me about the floor again. That’s the way it should be, as the floor should simply exist and the client shouldn’t ever have to think about it in a negative way.
View From the Kitchen
A little different perspective looking at the living room floor from the kitchen.
Close Up
Personally speaking, cork may be my favorite floor covering.
The article is very engaging and well-written. Thanks for sharing your knowledge and expertise with your readers.
This blog post was very informative and presented a unique viewpoint. Keep up the great work!