The next step in the Patio Project was to select an attractive and durable concrete finish so that the two concrete surfaces - old and new - appear consistent and neat. The challenge was to come up with a ceramic tile product and installation system that could withstand freezing temperatures in the winter.
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Completed Ceramic Tile Installation |
See my other posts regarding the concrete patio works -
enlarging and squaring off the patio with a 6" thick concrete extension and additional ground support, and the
selection and installation of an aluminum framed pergola structure with retractable vinyl awning.
Alternatives Considered
- Epoxy paint
- Teak wood slats applied to the surface
- Recycled plastic / synthetic planks or tiles applied to the surface
- Ceramic tile
- Interlocking brick
The key constraint was the lack of height between the top surface of the concrete and the door threshold entering the house. I wanted to maintain a height difference so that water during spring melt could not back up and flow into the house through the door. This effectively eliminated all the options except for epoxy paint and ceramic tile.
My other issue was the lack of surface finish consistency of the concrete between the old and new surfaces. The old concrete had been poured on a compacted earthen berm which was subsequently excavated. The top surface was not particularly well finished or flat. The existing epoxy paint provided a consistent color, but the surface finish was slick, slippery when wet and not particularly appealing.
So - we settled on ceramic tile as the selected finish. Next steps were to consider the type of tile and the tile installation system. Our climate is northern, with lows in the winter of -40F/C and considerable snow. The ceramic tile and installation system would need to be able to withstand freeze and thaw, and a temperature range from -40 to +40C for thermal expansion.
Surface Preparation
There were two principal concerns for surface preparation prior to ceramic tile installation. Removal of the old epoxy paint from the 25 year old concrete, waiting time for proper curing of the new concrete extension, and sealing the interface between the old and new concrete so that there wouldn't be movement between the old and new concrete which might lead to cracking of the ceramic tile.
First - I bonded and sealed the crack between the two concrete slabs using Sika crack fix. I got underneath the patio and sealed the bottom of the crack using adhesive tape, to help retain the Sika crack fix epoxy and manage the amount of material I would require. I then filled the crack in stages until I had pooling of epoxy on the surface.
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Note the interface between old and new concrete - sealed with Sika Crack Fix. |
Next step was to level the concrete surface, and remove as much of the old epoxy paint as possible. My local rental center had a scarifying wheel attachment for a floor polisher which I tried and was very effective. The wheel has angled diamond cutters around the perimeter of the wheel which were effective at removing not only the paint, but the high surfaces of the concrete.
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Diamond blade of the scarifying wheel. |
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Paint removal in process |
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Detail of the joint between the old and new concrete. Grouted with Granirapid. |
Surface prep was completed in a weekend.
Ceramic Tile Selection
We needed to consider a tile which would not absorb any water. This led us to a porcelain tile, rated for outdoor installation. We also sought tiles with a rough surface which would be less slippery when wet - to avoid falls with kids coming into the house out of the pool or in wet weather. It took some time but we finally settled on a tile from Italbec:
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Italbec Basalt Gray Ceramic Tile Samples |
Next task was to select the ceramic tile installation. I got into touch with Mapeii - they have a technical department which will advise on installation systems and applications. They were super helpful, and we settled on the Granirapid installation system. The Granirapid system is a modified polymer flexible grout system which dries rapidly and minimizes entrained water underneath the tiles - this has the advantages of reducing the possibility of efflorescence (white stains) and cracking or delamination from freeze and thaw movement. We added a shear barrier - Mapeguard - which helps to prevent cracking due to temperature changes between the ceramic tile on surface and the concrete structure below. In addition - we added flexible expansion joint strips every 10 feet to help manage thermal expansion.
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Mapeguard Shear Barrier - Green Material. Ceramic tile installed overtop using the Granirapid mortar system. |
Tile Trim and Joint Profiles
In my research I found a Schlutter balcony edge profile which looked like it would eliminate the requirement to bond ceramic tile on the vertical edges of the concrete slab. I went ahead with these profiles - they are available in a range of heights and colors. I selected a 6" high profile (the tallest available) in metallic gray color. My ceramic tile installer had never worked with balcony edge profiles before, but it turned out well and in the end, he thinks it saved him considerable time and aggravation.
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Schlutter Balcony Edge Profile |
An interesting feature of the profile is that by design, it allows water to escape from the tile system and drip down behind the profile - preventing a buildup of water which could lead to freeze cracks. The profile is easy to apply, using the tile mortar, and has corner profiles for a neat final appearance.
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Schlutter Balcony Edge Corner Profile detail |
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Expansion joint profile running laterally in the photo |
Conclusion
The Patio has been through 2 winters now, with absolutely no issues - no lifted tiles, no cracking or other damage. So far so good. To reduce the risk of problems, I try to keep snow accumulation to a minimum in the winter, so I don't end up with a glacier come spring time which might allow water to accumulate and penetrate the grout causing problems.
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The completed tile surface |
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Tile surface on the steps |
Sources and Links
My local sources for the ceramic tile was Italbec in Montreal. All the Mapei installation products were sources from Ciot in Brossard. All of the metal profiles were sourced from Marty's Carpet and Flooring in New York state, who managed to get the 6" balcony profiles in a matter of days from Schlutter's distribution center in upstate New York. Thanks to all the suppliers - they were all great.