This article is an effort to illustrate to you why so many solid surface areas outdoors fail.  There are so many products on the market these days and unless you take the time to do some homework, investigating the product and building codes approvals as well as the installers credentials you may well end up in a similar predicament.

This product is a liquid coating.  May of the coatings that are available are “allowed” by building code to retain as much as 15% moisture!  In harsh climates like ours this is clearly going to cause a problem in a short period of time.  Most offer a “warranty” but they require you to have the surface re-coated each 1-3 years depending upon the manufacture’s recommendations. Be sure and Ask! If you don’t maintain the ongoing requirements you may be without recourse.

These pictures show that the coating goes right up to the brick wall.  Since you really can’t apply the multiple layers in this system up a wall they simply stop here and apply a very generous layer of caulk.  Caulk not a good idea as your primary waterproofing. As you can see from the picture on the right the caulk shrunk, cracked (the sun can do this quickly) and the water that runs down the brick wall went right into the “caulked area and below the coating. The line you see at the bottom is the seam where two pieces of the substrate are joined.  Each sheet is expanding and contracting thus the hardened coating fails.  The area that looks blistered is from moisture in the substrate trying to escape.

Here you can see the problem is serious, it has spread across the entire deck.

What you are seeing here is the drip edge that was installed prior to the coating.  Not only is the drip edge showing as a result of poor installation technique but there is a separation or the left side is coming loose.  Again poor installation is to blame.  Not helping is the effect of the sun, this is west facing so they get a long period of direct sunlight and that metal gets very hot.  Each piece is going to “move” during expansion and contraction.

 These next couple pictures show a really poor way to try and flash the deck.

On the left you see a metal flashing was installed but there are some cracks forming and there is a hole in the corner.  Again one of the biggest issues to deal with is movement, expanding and contracting of the systems components. Wood (substrate)- Metal (flashing) and Coating (adhered to both). Each of these components will expand and contract at a different rate, the result is what you see here.

The issue here should be obvious.  Any water running down this column will simply go behind the metal flashing and right onto the substrate and the supporting joists. Not to mention the lighting and soffit installed below.
Surface mounted railings are very common and can be properly waterproofed.  Again unfortunately these were not installed correctly.
Not correctly waterproofing the surface mounted railing shown above resulted in the water damage you see below. There was about a half inch that was so rotted it just fell apart and had to be repaired so the rail could be re-installed.

The extent of water damages were serious but could have been even worse.

This is the underside of the substrate.  It was 3/4 inch thick and even the bottom is showing serious damage.

OSB should never be used outdoors as a substrate, often it is because it is cheaper than plywood.  Ask this home owner which is less expensive.

OSB acts like a sponge, any moisture is soaked in and it begins to swell.

Here it simply fell apart and left a good size hole.

When installed the sheet should have ended on the joist and been nailed in place (I assume that was done right) here you can see the sheet does  not reach the joist, shrunk? It is so soft I am pressing it down about an inch with just my fingers.  It is a wonder nobody fell through and was hurt.