QUESTION

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

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.