Articles
Essential Water Management in Exterior Tile InstallationsBy Sean Gerolimatos, Research and Development, Schluter Systems L.P.
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One of the primary areas to be addressed in designing such applications is water management. Water management extends beyond simply waterproofing and plays a role in many aspects of the assembly’s design.
Roofs and BalconiesUnlike patio and walkway tile applications that are located on grade, roof decks and many balconies are located over "occupied space." The definition of occupied space varies depending on who you talk to, but in general it is meant to indicate interior space or other sensitive areas of the structure that must be protected with structural waterproofing. Structural waterproofing requires familiarity and experience with specialized products (e.g., roof membranes) and flashing details and brings liability outside the scope of the tile installation. Unless the tile setter is experienced and insured for this type of work, it is best for all involved to engage the services of a qualified roofing contractor to install a roof membrane. Regardless of who installs the roof membrane, it should be sloped to allow water to evacuate the system. |
TROBA-PLUS is Schluter's durable subsurface drainage system that supports the floor with cone-shaped studs to create continuous drainage above the waterproofing layer.
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There are various types of roof membranes, such as built-up roofing using asphalt binders, modified bituminous systems, and single-ply |
The mortar bed is installed after placing a drainage layer over the roof membrane. The drainage layer has a higher permeability than the mortar bed, thus improving the water flow along the sloped roof membrane to the system exit. This helps prevent any buildup of water pressure on the membrane and reduces the potential for freeze/thaw damage to the mortar bed. Crushed stone has been used as a drainage layer, though various manufacturers offer lightweight drainage membranes that are configured to allow water to flow under gravitational force along the roof membrane. These drainage membranes also provide superior protection for the roof membrane.
Water Management: Sealed Systems or Water In/Water Out SystemsThe ceramic or stone tile covering is installed over the mortar bed using a sealed system or a water in/water out system. If the tile is gauged, meaning it features uniform thickness from tile to tile, it can be installed using the thin-set method. In this case, the tile setter needs to incorporate a bonded waterproof membrane meeting ANSI A118.10 directly below the tile. By creating this sealed system, moisture is not allowed to infiltrate the mortar bed, thus eliminating the potential for freeze/thaw damage or efflorescence due to a saturated mortar bed. Ideally, a bonded waterproofing membrane is chosen that also provides a forgiving shear interface to allow the tile layer and substrate to move independently. Incorporating such a membrane will protect the tile layer from damage due to differential movement stresses that would otherwise result from temperature gradients within the assembly. |
DILEX-BWB is a profile for use in movement joints.
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Regardless of the installation method used, movement joints must be provided in the tile layer to accommodate the expansion and contraction associated with temperature fluctuations. For more information, please refer to the appropriate industry standard guidelines, i.e., the Tile Council of North America’s (TCNA) Handbook for Ceramic Tile Installation, and the Specification Guide 09300 Tile Installation Manual published by the Terrazzo, Tile and Marble Association of Canada (TTMAC).
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Perimeter Water Management
The perimeter of the assembly is another area that warrants discussion with regard to water management. The importance of proper edge details is often overlooked, which can mean the difference between success and failure. For example, railing systems are a common source of leaks when not installed properly. It is advisable to choose under or side mounted railing systems when practical. If a top mounted railing system is the only option available, care must be taken to ensure that protrusions through the waterproofing layer(s) are properly sealed.
Schluter's BARA-RAK aluminum balcony edging profile fits the edges of finished sloped surfaces to form an edging and a drip lip.
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When the roof deck or balcony is sloped to the perimeter, water must be directed away from the structure using a drip edge of some sort. The drip edge must be placed such that it prevents moisture from wicking underneath the roof membrane, where it could otherwise damage the soffit or fascia. The drip edge should also be stilted from the structure to prevent the run off from leaving deposits on the walls that could stain the siding. For complete water management at the perimeter, a gutter system can be installed.
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Color coated aluminum BARA-RK is a T-shaped balcony edging profile with a protruding drip lip that covers the joint of the sub surface drainage system.
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Ceramic and stone tiles offer a myriad of design options and represent the premium surface coverings for homeowners. When proper installation techniques are used, including the appropriate provisions for water management, these materials can provide beautiful and durable surfaces in various exterior applications. Thus, exterior applications represent a great opportunity for the tile industry. |
Curing conditions: time, temperature, moisture and substrateThe setting and hardening of unmodified thin-set mortars is directly related to hydration of the Portland cement in the mixture. Hydration is the chemical reaction by which water combines with the cement to produce new compounds, the most important of which is calcium silicate hydrate (CSH). The CSH forms a dense matrix around the other hydration products, remaining unhydrated cement, and sand particles, creating the final hardened bond coat.
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Further information