QUESTION

Exterior Deck (balcony) is leaking - I have an exterior deck (balcony) that is leaking, it has white stains along the font face of it, and tiles seem to be loose. What could be causing this and what can we do to fix it?

ANSWER

ANSWER - Tiles whether ceramic tiles or natural stone or cement tiles should perform well on an exterior deck if installed correctly.  There tends to be a lot of failures with exterior decks because they are not designed or installed correctly.  Tile when installed correctly is a great surface and assembly for balconies.

Chances are when the tile was installed it was not installed per industry standards and it has several compounding defects.  Generally speaking when there is a problem it is not due to one single factor, but due to compounding defects.  Keep in mind that most installers do not learn their trade from a college or trade school, but rather learn on the job, so quite often they are not familiar with industry standards or the complexity of high risk applications such as an exterior deck that needs to be properly waterproofed.  When there are failures we commonly find the installers do not properly prepare their substrates.  The deck has to be treated like a shower pan for waterproofing.  We generally find they don't install a preslope over the waterproof membrane, or they don't have drains, or the membrane isn't properly installed, and the finish tile surface isn't sloped correctly.  We find that the installers don't back butter their tiles with the thin-set to ensure they get 95% to 100% attachment or/and that they don't properly key the thin-set into the back of the tile to ensure an adequate attachment.  Often there are not adequate expansion joints (movement joints) installed in the building and they may not be properly designed or installed correctly.  There are other factors too.

The only way to determine the extent of the problem and how to remediate it is to perform an intrusive inspection (destructive).  It is important to determine if the problem is an anomally or is it wide spread.

To avoid these problems a specific and detailed installation specification should be prepared that should include a quality control plan that should be in place to make sure the exterior decks are properly installed.   All high risk applications such as exterior decks, exterior veneers, showers, swimming pools and other exterior or wet applications should have a much higher standard-of-care for the installation and for quality control to ensure there isn't a failure that could result in thousands of dollars of damages.  Ceramic Tile and Stone installations are ideal for exterior and wet applications, but they need to be installed correctly.  For more details on CTaSC forensic investigations and quality control services visit our website at www.CTaSC.com.