Exterior Deck Tile Installation


Exterior Deck Tile Installation - We recently added a 2nd story "veranda" and covered screened porch to our home.Roughly 300 sq ft is outside exposed to the elements. climate temperatures reach 0 degrees and we have ice and snow as well as 100 degrees in summer.

Porcelain tile was used with the following specs: Coefficient of FrictionL Dry:0.65 Wet: 0.60 Durability Classification: Class IV; Glaze Hardness: 8.0 Mohs; Water Absorption:

The tile was installed over a cement backer board to an OSB subfloor using TEC Triple Flex adhesive. Is this considered a good installation.?


ANSWER - Exterior decks are known for commonly being constructed incorrectly.  Generally when there is a problem it isn't due to any single deficiency, but rather due to compounding deficiencies.  It is not only whether the deck was properly designed and whether you used the correct products, but were the products installed correctly.

First using OSB is not recommended.  It is not a stable substrate when it gets wet and can lead to problems.  If it is properly protected from moisture then it could work as long as the structure is structurally sound and doesn't have too much deflection.  Plus the surface of the OSB should have been sloped towards where the water is to drain.

The backer board is suppose to be screwed every 8 inches.  The sheets should have been staggered to each other.  The joints of the sheets should have been gaped filled and taped.  The lack of proper fastening could lead to excessive movement and resultant damages.

Having the tile set with TEC Triple Flex adhesive that could also be a moisture membrane is good to add more protection.  The question is if there is an adequate slope to drain on the surface of the tile to a drain or to a gutter along the edge to allow for proper drainage.

Only time will tell if it was constructed well enough to last without problems.  Good luck.


2 thoughts on “Exterior Deck Tile Installation

  1. Sep Golboo says:

    I recently had a leak from balcony which sits over my storage. The contractor hot moped the area and later the tile guy nailed the mesh wire into hot mop to secure it so it doesn’t move which lead to leakage again I had to demolish everything again and redo the hot mop. Now I need guidance as what next step is. How can concrete or deck mud stick to hotmop without nailing the mesh wire into hotmop damaging the membrane .

    • Donato Pompo says:

      Hot mop waterproofing is a very robust method of waterproofing shower pans or balconies. Industry standards shows that this type of installation should have a non-bonded mortar bed so you don’t penetrate the primary waterproof membrane. The mortar bed should be at least 1″ thick and suspended within the mortar bed is a 2×2 inch 16/16 galvanized or stainless steel wire mesh that meets ANSI A108.02.3.7 should be applied over the pre-sloped hot mop surface.

      You should have flashed the hot mop up the wall at least 3″ above the finished surface. If you put metal lath on the wall over the hot mop, you can pre-drill the holes and fill with an ASTM C920 sealant (caulking) prior to screwing in the fasteners to make the penetrations watertight.

      We would normally then apply a liquid applied waterproof/crack isolation membrane over the mortar bed and then bond the tile to the membrane so we can keep the moisture out of the mortar bed and provide added waterproof protection.

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