Prepping Decks Against Moisture
It's crucial to provide decks with a moisture-proof seal before placing tile.
Even in sunny Southern California, rain is still a reality of life. As such, the large outdoor living decks on the front and rear of the Sheldon Street house as well as the wood staircase on the south side will need to be properly sealed against moisture.
Custom Design & Construction has decided that because the decks will be tiled, the best approach is to slope the tile underlay away from the sliding doors and toward a pair of long, horizontal drains. Those drains will divert water to the gutter or sewer line, keeping the deck safe from moisture damage.
In order to ready the decks for that later step, a crew applies to the AdvanTech flooring a coat of high-tack, water-based contact adhesive and then applies strips of Bituthene, starting from the edge of the deck furthest from the house.
The strips continue toward the house in slightly overlapping layers. This method of overlapping layers, with the topmost layer closest to the house, centers on the law of gravity: Water won't flow uphill. Putting the topmost layer nearest to the structure creates an environment where any moisture that might breach the tile and grout will flow away from the house rather than down onto the wooden substrate.