Section 7 – Pool/Fountain/Spa Tile Installation

7.1 Adhesive and Mortar Performance and Selection Criteria

The performance and use of ceramic tile adhesives are regulated by the country or region according to prominent standards that govern the installation of ceramic tile. Some of these standards are discussed in Section 4. Compliance may either be mandatory or voluntary in the respective countries, depending on whether the standard is incorporated into a building code (see Section 4).

Criteria for Selection of Adhesives and Mortars

High Adhesive Strength (Tensile and Shear Bond Strength)

Water Resistant

Flexible (Differential Movement)

Permanent

Fire and Temperature Resistant

Non-Toxic and User Friendly

Good Working Properties (Open Time, Pot Life, Sag Resistance)

High Adhesive Strength (Tensile and Shear Bond Strength) – Shear stress occurs when a force is applied parallel to the face of the material. The greater the resistance to shear stress, the higher the shear strength result.

Tensile stress occurs when a force is applied to pull a material to the point where it loses bond with the surface to which it is applied. The greater the resistance to tensile stress, the higher the tensile strength result.

Tile and stone installations can experience both shear and tensile forces. It is important to note that shear bond testing is limited to laboratory testing. On the other hand tensile bond testing can be performed in both laboratory conditions and in the field. Therefore, both tests are applicable and suitable to measure a material’s bond strength.

Water Resistance – For proper exterior and interior wet area performance, and in demanding submerged applications, an adhesive must not be soluble in water after it is fully cured. The adhesive should also develop water insensitivity within 24 – 48 hours so as not to require an unreasonable degree of protection against deterioration when exposed to water.

Flexible (Differential Movement) – Adhesives must have a low modulus of elasticity, or flexibility, to withstand differential movement between the finish material and the underlying substrate/ structure. Differential movement can be caused by uneven or sudden temperature changes, moisture expansion or shrinkage of the finish material, substrate or structure, or, live loads such as filling and draining the tiled vessel with water.

Permanence – This criteria may seem obvious, but even if all other performance criteria are met, beware that some adhesive mortars can become soluble in submerged applications and may deteriorate over time. In addition, some epoxies can become brittle with age, and some urethanes can undergo a phenomena known as “reversion,” where the adhesive may soften and revert back to its original viscous state. Certain polymeric modification of cement mortars work only to enhance the workability and curing process to improve the physical characteristics of cement, but do not contribute any significant lasting improvement to the physical characteristics of the cement adhesive mortar.

Fire and Temperature Resistance – When cured, adhesives must meet building code requirements and standard engineering practices by not contributing any fuel or smoke in the event of a fire. In addition, the adhesive must maintain its strength and physical properties during and after exposure to high temperatures of a fire, or from absorption of heat under normal service.

Non-Toxic and User Friendly – The adhesive should be non-hazardous during storage, installation, and disposal. This includes other materials which may be necessary for preparation or final cleaning. The adhesive should be non-toxic, non-flammable, low odor, easy to use, and environmentally (VOC) compliant. It is always best to verify low VOC compliance by obtaining third party certification of the installation materials (e.g. GreenGuard). For example, LATICRETE International, Inc. manufactures a variety of setting materials for submerged applications (and otherwise) which are GreenGuard Indoor Air Quality Certified. For more information, please visit www.laticrete.com/green.

Good Working Properties – The adhesive should have good working properties to ensure a cost effective and problem-free installation. This means that the adhesives must be easy to handle, mix, and apply without having to take extraordinary precautionary measures. Good initial adhesive grab to substrate and the finish material, long pot life, long open time (tacky, wet surface after spreading), vertical sag resistance (both the adhesive alone and with tile), and temperature insensitivity are all recommended working properties.

Bedding of Tiles – Solidly bedding the tile is one of the most important steps to achieving a permanent and trouble free installation. Back-buttering the tiles and ensuring complete coverage without air pockets or voids is a key process to meeting this end. The Project Architect can specify this procedure in the installation specification to ensure that this essential step is part of the construction process. Inspectors and applicators should periodically remove a tile to verify the coverage that is being attained. United States ANSI A108 Standards require a minimum 95% coverage in wet areas. Ensuring that no voids exist will prevent water penetration into the adhesive mortar layer and into the pore structure of the tile or stone (see Section 6 for more information on the application of adhesives and how to achieve the correct coverage).

7.2 Methods of Installation

There are several methods generally used in the installation of tile in pools and water features.

Application Methods

Thin-Bed Method

Medium Bed Method

Thick Bed (Bonded Type Wet-Wet Method, Bonded Type Cured Thick Bed)

NOTE: Refer to Section 8 for unbonded, wire reinforced cured thick bed method and unbonded, wire reinforced wet-set method for natatorium pool decks and other non-submerged areas.

Thin Bed Method – This method, also referred to as the adhesive method, is defined as an application of a layer of adhesive, ranging from a minimum of 1/8" (3 mm) to a maximum of approximately 3/8" (9 mm) thick that is in full contact with no less than 95% of the bonding surface of the tile or stone and substrate. The substrate must be prepared to proper flatness, level and plumb in advance; adhesives are not intended for leveling or correcting level and plumb deviations. The adhesive can range from a pure or neat portland cement paste, to latex cement and epoxy adhesives. The thickness of the adhesive layer is dependent on the type and size of the tile, substrate bonding surface texture, and configuration of the tile (flat or ribbed back). A “gauged” tile is one with a consistent thickness and a specified tolerance for deviation; an ungauged finish material type is not consistent in thickness and typically requires thick bed or medium bed methods of installation. Generally, most, redispersible powder polymer and latex cement mortars are suitable for use with the thin bed or adhesive method, but not all of these mortars are suitable for submerged installations. Follow the adhesive manufacturer’s guidelines for limitations on thickness, which varies based on formulation and for suitability in submerged installations. Refer to Section 9 – Specifications and Section 10 – Detail Drwaings for ES-P601D for more information.

Medium Bed Method – Generally, thicknesses over 3/8" (9 mm) are not recommended for standard thin-bed or adhesive types of cement mortar mixes. Thickness over 3/8" (9 mm) typically require either a special formulation of powder containing a higher proportion of coarse sand, or modification of a site mix with the addition of extra coarse sand. These products are also known as medium bed mortars. Medium bed mortars are typically used when the adhesive thickness ranges from 1/8" (3 mm) up to 3/4" (19 mm). An example of this type of mortar is LATICRETE® 220 Marble & Granite Mortar mixed with LATICRETE 3701 Mortar Admix (ideal for use in submerged applications).

Figure 7.1 – Trowel applied medium bed mortar with a 3/4" (19 mm) loop notch trowel.

Thick Bed Method – Also known as the “wet-set" or “float and back-butter” method of installation, this method encompasses several different techniques. The most common thick bed technique is the “float and back butter” method. This method starts with the floating or screeding of the substrate with cement leveling mortar. The mortar bed can either be of the unbonded type (for pool decks) or the bonded type (pool decks or submerged). Mortar beds and wall renders are very commonly used in pool and water feature applications. Mortar beds allow for the creation of proper pitch/falls to drains, slopes in pools and decks and the creation of coves and transitions as pool floors slope and the depth changes.

Bonded Type (Floors) – In the bonded type for floors, a slurry bond coat consisting of LATICRETE 254 Platinum, or, LATICRETE 211 Powder gauged with LATICRETE 4237 Latex Additive is trowel or brush applied to the concrete substrate. While the slurry bond coat remains wet and workable, the mortar bed (e.g. LATICRETE 3701 Fortified Mortar Bed or LATICRETE 226 Thick Bed Mortar mixed with LATICRETE 3701 Mortar Admix) is placed, compacted and then screeded, leveled, and pitched as required. The above mentioned mortar bed and slurry bond coat products are ideal for use in submerged applications. Unbonded mortar bed types require wire reinforcing which can be subject to corrosion in submerged applications and are therefore, unsuitable for use in this type of application.

Bonded Type (Wall Renders) – Wall renders do not require the use of slurry bond coat beneath them as the mortar is mixed to a more plastic mix containing a liquid to mortar powder ratio. This consistency allows the cement paste to wet out the concrete/masonry substrate in a sufficient manner to achieve proper bond. Wall renders are generally applied in several lifts with each lift never exceeding 1/2" (12 mm) in thickness. The first lift is the scratch coat. This layer is applied to the wall and is scratched up with a small metal comb like tool or trowel that roughens up the layer in order that the subsequent layer will achieve better mechanical bond. The scratch coat is allowed to harden and then the subsequent “brown” coats are applied in the same 1/2" (12 mm) maximum lifts. If additional lifts are required, the previous brown coat should be scratched up before it hardens.

LATICRETE 3701 Fortified Mortar Bed; and, LATICRETE 226 Thick Bed Mortar gauged with LATICRETE 3701 Mortar Admix are pre-packaged thick bed and rendering mortars which comply with industry standards and will hold up to the rigors of submerged applications. The use of pre-packaged mortars eliminates inconsistencies in job site powder proportioning and raw material quality. Refer to Section 9 – Specifications and Section 10 – Detail Drwaings for ES-P601 for more information.

These products are also components of the LATICRETE System Warranties and apply to submerged installations Please visit www.laticrete.com for more information on LATICRETE warranties or call LATICRETE Technical Services at 1.800.243.4788 x235.

Figure 7.2 – Latex fortified render is being applied to wall surface. Notice the lath strips that are set into the mortar. The lath strips are leveled and plumbed to establish the correct wall render depth. Once the render achieves a sufficient cure, the lath strips are carefully removed and the cavities are filled with mortar.

Templates – Swimming pools and water features may include intricate shapes, coves, goosenecks and other special attributes that can only be achieved by careful placement of bonded mortar beds and wall renders. Wood form templates are created and used to screed and shape the mortar to conform to these unique shapes. Traditional pools generally used formed tile gutters/skimmers/drains/ladders as part of the design and functionality.

Tile mechanics will often spend many hours fabricating these templates to create these intricate flowing shapes. This is a critical step in establishing the correct depths and elevations of the finish tile. In many cases, the shaped tile gutters and gooseneck dictates the finished elevations of the balance of the pool tile assembly including the pool deck.

Figure 7.3 – Tile mechanics float and shape pool utilizing templates, floats and screeds to achieve the desired form and height of the renders and mortar beds.

Figure 7.4 – Mechanic is using a wooden template to shape and screed the swale in the water feature tank.

Gutters and Special Forms – Modern pools generally use stainless steel gutters in lieu of the formed tile gutters. The stainless steel gutters also help to set the depth of the wall renders and the finish tile height. These elevations have a direct bearing on the floor heights and the radius of the coves that tie the walls into the floors.

Figure 7.5 – Stainless Steel Pool Gutter Assembly. Tile or Stone is brought up to the gutter assembly in the tank and on the deck (Photo courtesy of Barrier Lining, Inc.)

Figure 7.6 – Uniquely shaped pool/deck rim which required careful forming of the render in order to place the finished tile.

7.3 Waterproofing

Importance – Waterproofing protection is one of the most practical steps to ensure the longevity of any tile installation. It not only protects the spaces below and adjacent to the tile installation, it also protects the setting bed, reinforcing wire or metal lath (if used), concrete base and concrete reinforcing from potential damage and corrosion. Since damage to components can occur, it is no surprise that the majority of construction liability claims involve water damage that has resulted from the lack of, or an improperly installed, waterproofing membrane. The pressure of completing projects in a timely manner, often leads to tile installations being rushed and not installed correctly. The advanced technology that goes into waterproofing and anti-fracture membranes allows the end user to take advantage of quicker curing times, allowing quicker time to flood testing and ultimately allows the tile installation to move forward in a timely fashion. Various types of waterproofing and anti-fracture membranesare available and include; troweled applied, liquid applied and sheet good types. The traditional asphaltic/bitumen based roofing type waterproofing membranes are omitted from this manual. However, it is important to note that if they were to be specified and used in a swimming pool or water feature, a topping concrete slab would need to be placed over this type of membrane. Direct bonding of tile or stone to these membrane types is not possible.

The most important factor in all types of waterproofing membranes is to closely follow the membrane manufacturer’s installation recommendations. This will significantly reduce the possibility of job site problems and potential failures. Adhering to industry standards is also paramount to the success of the tile installation. Consideration should be given to membranes that carry plumbing and building code approval as well as being environmentally friendly (e.g. LATICRETE® 9235 Waterproofing Membrane or LATICRETE Hydro Ban).

Many crack isolation and waterproofing membranes can be applied over concrete, mortar beds, exterior glue plywood (interior only) and cement backer board. Some waterproofing membranes serve as both waterproofing and anti-fracture membranes (e.g. LATICRETE 9235 Waterproofing Membrane or LATICRETE Hydro Ban).

The installation of waterproofing is covered under ANSI A108.13, Installation of Load Bearing, Bonded, Waterproof Membranes for Thin-set Ceramic Tile and Dimension Stone, and crack isolation is covered under ANSI A108.17, Installation of Crack Isolation Membranes. The product standards for waterproofing can be found under ANSI A118.10 and the product standards for crack isolation membranes can be found under ANSI A118.12. Selection of membranes must take into account the conditions of a submerged application including exposure to pool water chemicals. Direct bond waterproofing membranes protect underlying leveling mortars and the concrete shell from saturation and prevent problems caused by moisture penetration such as moisture expansion, chemical attack (e.g. chloride ion deterioration of reinforcing steel), and efflorescence. LATICRETE products in this category include LATICRETE 9235 Waterproofing Membrane and LATICRETE Hydro Ban.

External “Sandwich” Type Roofing Membrane – In suspended, exterior roof swimming pool and water feature applications over occupied space, primary roofing membranes can be specified to be installed in between two concrete pours that serve as the platform or substructure of the water feature. These external type roofing membranes are also typically used when external or negative hydrostatic pressure is present to protect ceramic tile from delamination when pools are emptied. A concrete topping slab is required in order to protect the membrane from damage and to provide a suitable substrate to receive subsequent work. These types of primary roofing membranes can be bituminous asphaltic, neoprene, PVC or other durable bladder type material. Ceramic tile and stone cannot be bonded directly to these types of membranes.

Sheet membranes – Sheet membranes are typically made from chlorinated polyethylene, polyvinyl chloride, or other materials. Sheet membranes are made in a variety of lengths and widths to accommodate many different types of installations, with product performance that can vary depending on the manufacturer and product type. Generally, these sheet membranes have polyester or fiberglass mesh or scrim bonded to both sides of membrane sheet which allows the membrane to be bonded to the substrate, and tile or stone to bond directly to the sheet membrane. Check with the sheet membrane manufacturer for suitability in submerged installations.

Typically, a latex portland cement mortar (meeting ANSI A118.4) is used to bond the membrane to the substrate and to bond tile to the membrane. If time is a limiting factor, some membrane manufacturers allow the use of a rapid-setting thin-set to adhere the membrane to the substrate, which in turn allows the installation of tile to take place immediately without the loss of bond from the membrane to adhesive.

It is very important to consider the moisture vapor emission rate (MVER) and the alkalinity of the concrete slab prior to the installation of the products. A high MVER rate and/or high alkalinity can create adhesion problems and can even be destructive to the membrane and the overall installation. The sheet membrane manufacturer can provide information on the MVER and alkalinity limits of their products.

Sheet type membranes are pressed into contact with the substrate in an effort to eliminate air bubbles and voids between the membrane and substrate. Generally, this can be done using a 75– or 100 (34 – 45kg) pound sheet vinyl roller. It is important to note that the substrate or setting bed surface must meet the same substrate smoothness criteria required for direct bond tile applications. Basically, if the surface is not smooth and flat enough for tile, then it is not smooth and flat enough for a membrane.

Precautions and concerns with sheet type membranes are as follows:

1. Trapping air below the membrane can cause air pockets to form and radically diminish the compressive strength of the membrane.

2. Overlapping and sealing the seams. The seams may require treatment with a suitable sealant or solvent. This process can be very involved and requires careful attention to detail and safety concerns.

3. Membrane thickness increases in the folds of inside and outside corners, seams and other transition areas. Additional flashing or skim coating treatment may be necessary to minimize the effects that this can have on the finish tile appearance.

4. High alkalinity and moisture can attack and adversely affect some sheet type membrane and the adhesive used to adhere the membrane to the substrate.

5. High MVER – generally in excess of 5 lbs/1000 ft2/24 hours (283 mg/s m2) can have a negative impact on the adhesion of sheet type membranes (follow membrane manufacturer’s guidelines for MVER).

Peel and Stick Membranes – Peel and stick membranes are very similar to sheet type membranes in performance. The major difference between the two styles is that the peel and stick type does not rely on a separately applied thin-set or adhesive to bond it to the substrate. These membranes are generally asphalt based with a reinforcing fabric on the tile bonding side of the membrane and a removable Kraft paper type backing which exposes a tacky surface once it is peeled away. The installation of peel and stick membranes begins with priming the substrate with the appropriate primer for the application. Some primers are latex based types and others can be epoxy based materials.

Once the primer is in place, the removable film is peeled from the back side of the membrane and rolled onto the primed substrate.

Check with the peel and stick membrane manufacturer for suitability in exterior or wet area installations.

Precautions and concerns with peel and stick type membranes are as follows:

1. Careful consideration must be taken where the seams overlap. Spreading the tile mortar over the seam can be tricky and care should be taken to avoid humps where the tile lays over seams.

2. These types of membranes have a tendency to soften when exposed to sunlight. Windows that face the sun and let more sunlight in could pose problems for peel and stick membranes.

3. Cleaning regimens also play a factor in whether peel and stick membranes should be used or not. Solvents typically have an adverse effect on this type of membrane. Consult the manufacturer for specific applications.

4. Use of these membrane types should be limited to pool decks and other intermittent wet areas. These membranes should not be used in submerged applications.

Trowel Applied Membranes – Trowel applied membranes come in various forms, including latex fortified cement based types, epoxy resin types and urethane types. Some of the trowel applied membranes include a reinforcing fabric used in corners, coves, and to tie into plumbing fixtures (including drains). After the typical pre-treatments are made to cracks and transition areas, the main application normally consists of keying the membrane into the substrate with the flat side of the trowel. This is immediately followed by combing the material in a singular direction, and then finally another pass with the flat side of trowel to smooth the surface. A few key elements are the notches in the trowel which act as a gauging device for the membrane. Most membranes require a certain thickness of product to ensure complete waterproofing coverage. As with all waterproofing membranes, the products should be applied at the continuous required mil thickness to ensure waterproofing integrity. The use of a wet film gauge is recommended to assure acceptable uniform thickness.

Check with the trowel applied membrane manufacturer for suitability in submerged installations.

Latex Cement Based Membranes – This membrane type is generally comprised of a liquid latex polymer that is mixed into a portland cement based powder. These products are generally very economical in cost and in ease of application. However, the physical characteristics of these types of products generally restrict their use in demanding submerged applications.

Check with the latex cement based membrane manufacturer for suitablity in submerged installations.

Epoxy Based Membranes – Epoxy membranes are normally 3-component systems consisting of an epoxy hardener, epoxy resins, and a filler powder. These products are generally very chemical resistant and suitable for submerged applications. Some other advantages to this category type of waterproofing are as follows:

Flood Testing Can Be Performed in 24 Hours at 70° F (21°C)

Adheres to Metal, Such as Stainless Steel, as Well as Metal Plumbing Fixtures

Flexible and Able to Adhere to Most Substrates

Can Be Used as a Flashing Membrane to Tie Into Other Types of Membranes or Surfaces When Required (e.g. Pipe Penetrations, etc…)

An example of this category type of waterproofing membrane is LATAPOXY® 24hr HydroProofing.

Figure 7.7 – Epoxy waterproofing membrane is applied at the pipe penetrations over the cured liquid applied waterproofing membrane to ensure a complete seal at the penetrations.

Liquid Applied Membranes – This category type offers an ideal solution to the demanding requirements of submerged tile and stone applications. In addition, to holding up under normal conditions in these applications, liquid applied waterproofing membrane types are the easiest to install and provide many features and benefits. These features and benefits include:

Providing Both Waterproofing and Anti-Fracture Protection

Meet ANSI A118.10 Standards for Waterproofing

Meet ANSI A118.12 Standards for Crack Isolation

Plumbing Code Approved (IAPMO and ICC)

Green Building Approved for Low VOC Content (GREENGUARD® Certified)

Thin – Load Bearing

Shock Resistant

Fully Compatible With the Entire Range of Ceramic Tile or Stone Installation Materials Which are Recommended for Submerged Installations

Fully Formable to Fit Into Tight Areas

Can Be Shaped to Follow Any Substrate Contour

Flood Testing Can Vary According to the Membrane Type and Generally Ranges From 2 Hours to 7 Days at 70° F (21° C)

Some Liquid Applied Waterproofing Membranes (e.g. LATICRETE® Hydro Ban) May Be Spray Applied With a Commercial, Airless Sprayer

Figure 7.8 – Liquid applied membrane applied to concrete substrate.

Figure 7.9 – Full scale view of liquid applied waterproofing membrane on a large scale pool project.

Examples of this category type are LATICRETE Hydro Ban and LATICRETE 9235 Waterproofing Membrane. LATICRETE Hydro Ban is a thin, load bearing waterproofing membrane that does not require the use of reinforcing fabric in most situations, and, LATICRETE 9235 Waterproofing Membrane which is a cold liquid applied, fabric reinforced membrane that is thin, load-bearing and completely compatible with LATICRETE latex thin-set mortars.

Detailing Of Penetrations/Railings/Steps –Detailing of penetrations through the waterproofing membrane and tile or stone finish is one of the most critical areas of a submerged application. Generally, a suitable flexible sealant designed for these applications is a key component to treating penetrations. Railings, ladders, drains, gutters, filter inlets and outlets, lights, and receiver hooks are among the list of items that could potentially penetrate the waterproofing membrane in a submerged application. Silicones (e.g. LATICRETE® Latasil) and urethane type sealants offer solid performance in these applications. In many cases, manufacturers of these products will also offer primers that aid the sealant’s ability to remain adhered in these applications (e.g. LATICRETE 9118 Primer). Each penetration through the waterproofing membrane and finish is unique. Therefore, consult with the tile and stone installation materials manufacturer for their suggestions on compatible penetration treatments. See Section 10 for details ES-WP-300 for information on the treatment of pipe penetrations and ES-WP301 and WP-302 for information on the treatment of drain assemblies.

Figure 7.10 – Detail treatment of the pipe penetrations in this pool application. Liquid applied waterproofing membrane is double applied at the penetrations to ensure adequate reinforcement and protection. This pool is now ready for the full waterproofing treatment.

Flood Testing – Flood testing criterion can also vary according to the type of water feature application. Generally, a flood test is conducted after the waterproofing membrane and penetrations through the membrane are treated and all installed components reach full cure.

Although there are no known flood testing standards for pools and water features, ASTM D5957 “Standard Guide for Flood Testing Horizontal Waterproofing Installations” can serve as a basic guide for flood testing submerged applications. Generally, flood tests are conducted for a period of 24 – 72 hours and must be continuously monitored during the flood test period. Please note that accumulation of rain water, or water from any other outside source, may render the results of the flood test inaccurate.

Most latex fortified portland cement based installation systems (mortar bed, thin set mortar and grout, flexible sealant) require a minimum 14 day cure at 70°F (21°C) after the final grouting period prior to the initiation of the flood test. If an epoxy grout is used, the minimum cure can be reduced to a 10 day cure at 70° F (21°C) after the final grouting period.

As a rule of thumb, water is placed into the water feature at a rate of 1' (25 mm) per hour. Flood tests are generally conducted for 24 – 72 hours. All piping and drains will need to be plugged and isolated to eliminate the potential for the plumbing as a cause of water loss. If any measurable water loss is observed, the following process will be required:

The Water Feature Will Need to be Drained at the Same Rate Used to Fill the Tank (2' [600 mm] per 24 Hours)

Allow the Water Feature to Dry

Inspect For Leaks

Repair the Leaks

Allow the Installed Products to Reach Full Cure

Repeat Flood Test Procedure Until Successful

Figure 7.11 – Waterproofed pool tank is curing and awaiting a flood test. Curing term of waterproofing membranes can vary by manufacturer. Consult with waterproofing manufacturer for detailed information on cure rates and flood testing processes.

For more information on flood testing procedures, please refer to TDS 169 "Flood Testing Procedures" available at www.laticrete.com.

Figure 7.12 – Pool tank is filled with water during the flood test stage. Upon successful flood testing, the pool will be drained, dried and ready to be tiled (as a side note, notice the tenting that is protecting the water feature from the elements during the installation and curing process).

7.4 Tile Setting Mortars

Types of Adhesives

Redispersible Polymer Fortified Cement Mortar (Mixed With Water)

Liquid Latex Fortified Cement Mortar (Latex in Lieu of Water)

Modified Emulsion Epoxy Adhesives (Cement, Water, Epoxy Resins)

Epoxy Resin Adhesives (100% Epoxy)

Redispersible Polymer Fortified Cement Mortar – This type of cement based adhesive mortar is available only as a manufactured proprietary product. There are a wide variety of these types of adhesive mortar products on the market. These materials typically are mixed with potable water; however, many redispersible polymer mortars can be mixed with liquid latex additive to improve performance (see latex fortified cement mortar). For example, LATICRETE 220 Marble & Granite Mortar can be mixed with either water for good performance or with LATICRETE 3701 Mortar Admix for improved performance. In fact, for submerged applications, LATICRETE 220 Marble and Granite Mortar must be mixed with LATICRETE 3701 Mortar Admix. These adhesive mortars differ mainly by the type and quantity of polymeric content. In addition, premium high strength redispersible polymer fortified thin bed mortars are available and suitable for use in submerged applications. For example, LATICRETE 254 Platinum is ideal for these areas. Performance characteristics of LATICRETE 254 Platinum comply with both ANSI 118.4 and 118.11 standards. Please visit www.laticrete.com for more information on each LATICRETE product including mixing instructions.

Types of Redispersible (Polymeric) Powders

Modified Cellulose

Polyvinyl Acetate Powder (PVA)

Ethylene Vinyl Acetate Copolymer Powder (EVA)

Polyacrylate Powder

Many of the redispersible powder cement mortars available on the market are not recommended for submerged applications for a variety of reasons. Some of the polymers used, such as PVA, are water soluble and can re-emulsify after prolonged contact with moisture, causing polymer migration and resulting in staining, loss of flexibility and strength. Most products that conform to ANSI 118.1 adhesive standards contain only water retentive additives such as cellulose, which provide water retention for prolonged open time and improvement of working properties, but ultimately provides minimal improvement of strength or flexibility when compared to traditional cement mortar.

EVA modified mortars that conform to ANSI A118.4 standards may require special formulation and vary in quantity of the polymeric powder in order to have the characteristics and physical properties required for an industrial application. Some products which employ EVA polymers do not have good resistance to prolonged moisture exposure and are not recommended for submerged applications. While dry redispersible polymer fortified adhesives are economical and easy to use, it is recommended to verify suitability for use in submerged applications with the manufacturer, and to request or conduct independent testing to verify the manufacturer’s specified performance.

Liquid Latex Fortified Cement Mortar – There are a wide variety of proprietary liquid additives that can be used with both generic cement (and sand), or with proprietary cement mortar powders, including the previous category of redispersible polymer fortified mortars, to prepare an adhesive for submerged tile installations. As with redispersible polymer products, the liquid additives differ mainly by the type and quantity of polymeric content. Therefore suitability and performance characteristics for water feature applications must be verified. LATICRETE® 317 fortified with LATICRETE 3701 Mortar Admix or LATICRETE 211 Powder fortified with LATICRETE 4237 Latex Additive are examples of these types of products. Also, LATICRETE 3701 Fortified Mortar Bed or LATICRETE 226 Thick Bed Mortar gauged with the 3701 Mortar Admix fall into this category.

In addition, LATICRETE 1500 Sanded Grout gauged with LATICRETE 4237 Latex Additive can be used for the one-step method of setting and grouting paper or plastic face mounted mosaic tiles in accords with ANSI A108.14 – Installation of Paper Face Glass Mosaic Tile. Traditional “spacing” mix (typically dry cement powder and grout) can create hollow, drummy areas in the tile installation. It would be better to use the LATICRETE one step method as detailed in LATICRETE TDS 145 “Installation of Glass Mosaic Tile” which is avaialble at www.laticrete.com.

Types of Liquid Additives

Vinyl Acetate Dispersions

Acrylic Dispersions

Styrene-Butadiene Rubber

Liquid polymer modified cement mortars are also a good choice for submerged applications. However, as with redispersible polymer powder mortars, not all liquid additives mixed with cement based powders are suitable. Both, the type and quantity of latex, as well as other proprietary chemicals, will determine if a liquid additive is suitable for these applications. A common and highly generalized misconception is that either acrylic polymers or styrene butadiene rubber are superior to one another. This is not true. Both polymers can be formulated to have high adhesive strength, and be equally flexible. Superior performance is achieved through the formulation of these two materials. It is recommended to verify the suitability of a latex additive for pool applications, and conduct or request independent testing to verify the manufacturer’s specified performance.

Figure 7.13 – Installation of mosaic tile with liquid latex fortified portland cement thin-set mortar.

Figure 7.14 – Installation of glazed porcelain tile with liquid latex fortified portland cement thin-set mortar over a liquid applied waterproofing membrane.

Epoxy Resin Adhesives – This type of adhesive is typically a three component system, consisting of epoxy resin and hardener liquids, and some filler type material, such as silica sand. Epoxy adhesives which conform to ANSI A118.3 contain 100% solids epoxy. LATAPOXY® 300 Adhesive is a high strength, 100% solids epoxy that works well for submerged applications. These adhesive mortar types are required for use when tiling directly to steel or fiberglass pool tanks. Refer to Section 9 – Specifications and Section 10 – Detail Drwaings for ES-P602 and ES-P603 for more information.

Figure 7.15 – Mosaic tiled stainless steel pool tank. Only an epoxy adhesive can be used to install tile directly to steel tanks. (Photo courtesy of Bradford Products, LLC).

In addition, while the grouting materials will take the brunt of any potential chemical attack, some chemicals and strong cleaners can work their way through the tile and even attack the tile or stone adhesive over an extended period of time. Therefore, it is important to consider this potential problem exists. The use of LATAPOXY 300 Adhesive can ensure the long term performance of an installed water vessel that may be exposed to chemical attack.

More economical versions of epoxy adhesives, known as modified epoxy emulsions, are also available in the market. Modified epoxy emulsions which conform to ANSI A118.8 consist of special epoxy resins and hardeners which are emulsified in water, and then mixed with cement mortar. This type of epoxy adhesive combines the economy of cement based mortars and the high strength of epoxy adhesives. An example of this type of material is LATAPOXY 210 Adhesive. The advantages of epoxy adhesives are that they have exceptionally high adhesive strength (shear bond and tensile strength) to most any type of substrate material suitable for a tile installation, and more recent formulations have good flexibility to accommodate differential movement. While modified epoxy emulsions typically have lower strengths than 100% solid epoxy resin adhesives, they benefit from the higher temperature resistance and economy of portland cement adhesives.

The primary disadvantages are that epoxy adhesives can be significantly more expensive, and the working qualities in cold or warm temperatures can limit production and further escalate costs. Sag resistance and temperature resistance are secondary limitations, depending on the requirements for the installation. Epoxy adhesives can bond to virtually any suitable substrate which is structurally sound, so they are often recommended as a supplementary adhesive to more economical cement based systems when the tile or pavers must be adhered to unusual substrates such as steel or fiberglass pool tanks.

7.5 Grout

Importance – As is the case in any tile or stone installation, the grout is the most visible and most scrutinized part of the installation system. In submerged applications, the performance of the grout is critical to the long term durability of the installation system. Therefore, the selection and use of the appropriate grout is a key design element. Grout in submerged applications can be exposed to chemicals, pH imbalance, varying water mineral and metal content levels, moisture expansion and other factors that could affect the integrity of traditional cement based grouts. In addition, for grout exposed above the water line, consideration for UV resistance must also be made. Therefore, it is important to specify a grout that can withstand all of the potential issues that can develop (e.g. LATICRETE SpectraLOCK PRO® Grout). In many commercial and public water features, pH pool water imbalance can lead to degradation of cement grouts. In addition, calcium extraction of the portland cement component of traditional cement based grouts can occur when prolonged mineral imbalance occurs (see Section 11 for further information). Epoxy grouting products are resistant and immune to these issues. Epoxy grouts are also more resistant to harsh cleaners and chemicals that may be used to clean and maintain institutional and therapeutic pools which are emptied, cleaned on a frequent basis and then filled again.

Latex Cement Grout – Similar to the same adhesive mortar category, latex-fortified grout is a combination of either a proprietary pre-mixed sand-cement (and pigment) powder, or site mixed cement-sand grout powder with a ratio of approximately 1:2 by volume for joint widths to 1/2" (12 mm), gauged with a liquid latex or acrylic polymer additive. As with polymer modified grouts, the liquid latex or acrylic additive must be formulated for wet areas. An example of this product type is LATICRETE® PermaColor Grout^. Cement based products also have limited chemical resistance and are generally only used where no exposure to chemical attack occurs. If a cement based grout is selected for a water feature, careful detail to the maintenance regimen is a must. At times the extra cost associated with additional maintenance of a cement-based grouted water feature can be offset with the selection and use of an epoxy grout that will greatly reduce the maintenance required.

Epoxy Grout – ANSI A118.3 compliant grouts are chemical resistant, water cleanable grouting epoxies. These grouts are epoxy compositions; essentially a 100% solids system that are supplied in two or more parts to be mixed immediately before use as a joint filling grout for ceramic tile, and that is partially emulsified by water, after mixing, in order to expedite cleaning from tile surfaces during application before the epoxy hardens. Both LATICRETE SpectraLOCK® PRO Grout and LATAPOXY® SP-100 comply with ANSI A118.3. These types of grouts are the ideal choice for water feature applications. Epoxy grouts offer both lower water absorption rates and improved chemical resistance when compared to traditional cement based grouts, and epoxy grouts are immune to the typical attack that traditional cement based grouts can face.

7.6 Sealant

Importance – Sealants are typically used as a joint filler material only in movement joints, changes in plane, between dissimilar materials in an application (such as steel gutters and the tile installation), and where a high degree of adhesion and resistance to differential movement and tensile or compressive stress is required. Movement joints are intended for relief of significant stress build-up that may be transmitted over a larger area, and sealants must have the characteristics to resist much greater elongation or compression than more rigid materials like cement. These materials also adhere to dissimilar materials such as steel gutters, metal window frames, penetrations, and drain covers to not only maintain a water barrier where a more rigid material may fail, but also to accommodate the significantly different thermal movement characteristics of some dissimilar materials such as aluminum and steel.

Movement joints that are in the field of the installation must allow for the anticipated movement, while maintaining a waterproof barrier. In these cases, the waterproofing membrane (e.g. LATICRETE Hydro Ban or LATICRETE 9235 Waterproofing Membrane) is “looped” down into the movement joint to enable the joint to move freely while the waterproofing membrane continues to function (see figures 7.16, 7.17, 7.18 and 7.19). A liberal amount of waterproofing liquid is applied on both sides of the expansion joint (at least 4" to 6" [100 mm to 150 mm]) and into the joint opening. While the liquid is wet and tacky, the waterproofing reinforcing fabric is folded and placed into the movement joint opening and folded over onto the side of the concrete or mortar bed. Immediately, saturate the waterproofing reinforcing fabric with additional waterproofing membrane liquid. The fabric treatment must have enough “slack” to go down deep enough into the expansion joint to accommodate the anticipated joint movement. After several hours, another coat of waterproofing liquid is applied to this treatment to ensure a complete seal. Next, the full waterproofing membrane treatment with fabric is placed over the pre-treated expansion joint areas following the same looping profile. Therefore, the expansion joints have a “double treatment of looped fabric”. These joints must be honored and must come up through to tile or stone finish and treated with backer rod and a suitable flexible sealant. (See Sections 4 and 10 for more information on the use of flexible sealants in expansion joints).

Always check with the manufacturer of the sealant and primer for acceptability in submerged applications.

Backup Strip (Backer Rod) – The use of the rounded backup strip in movement joints is necessary to regulate the depth of the sealant for proper width/depth ratio and to prevent three sided adhesion. Typical sealant joint depth is 1/2 the width of the joint. The backer rod should be set into the joint to achieve this ratio. Sealants perform optimally when adhesion occurs only at the joint flanks (two-sided bond). The backer rod also helps to transmit the tooling force of the sealant to achieve bond to the tile edges. Polyethylene bond breaker tape can be used for thin bed applications where backer rod cannot be utilized. The polyethylene bond breaker tape also helps to prevent three-sided bond.

Typical back up strip materials are flexible and compressible and fall into one of the following categories:

Closed Cell Foam Polyethylene (Best For Submerged and Wet Area Applications)

Butyl Rubber

Open Cell Polyurethane

Closed Cell Polyurethane

Silicone – Single component, mildew resistant 100% silicone sealants are suitable for use in submerged water feature applications. An example of this type of sealant is LATICRETE Latasil.

These sealants usually fall into the following category:

ASTM C90 which designates sealants according to Type, Grade, Class and Use

– Type S – Single component

– Grade NS – Non Sag

– Class 25 – Sealant can withstand an increase and decrease of +/- 25% of joint width

– Uses M and G – Sealant will remain adhered to mortar (M) and glass (G)

Silicone sealants can also be supplied with a primer that will improve the adhesion of the sealant to the joint flanks. An example of this type of primer is LATICRETE® 9118 Primer. The two most common ways to specify sealants are:

1. List the manufacturer and brand name(s) of the acceptable products.

2. Specify the characteristics by description and / or by reference to standards.

Urethane or Polyurethane – Urethane based sealants that do not employ the use of solvent based primers are also suitable for use in submerged applications provided that they fall into the same ASTM C90 categories as listed under silicone sealants.

Acrylic – Typically, acrylic sealants are used for interior non-wet areas. Therefore, the physical properties of acrylic sealants/caulks preclude their use in water features and submerged applications.

Figure 7.16 – Waterproofing liquid is applied onto the sides and into the expansion joints.

Figure 7.17 – Waterproofing reinforcing fabric is then folded and placed into the movement joint and folded onto the concrete/mortar bed. Additional waterproofing liquid is applied over the treatment. A third coat of liquid is then applied to seal off the entire treatment.

Figure 7.18 – Profile view detail depicting the waterproofing membrane looped into the movement joint.

Figure 7.19 – View of completed swimming pool. Note the movement joint at the changes of plane on the floor of the pool and the other field movement joints on the walls and floors.

Figure 7.20 – View of completed swimming pool. Note the movement joint running continuously through the width of the swimming pool both at the walls and floors. A properly placed water stop in the concrete shell is a critical design element to ensure system functionality.

7.7 Post Installation

Cure Times – Typically the following cure times should be observed after the final grouting period in swimming pools and water features: Observe a minimum cure time of 14 days at 70°F (21°C) for latex fortified portland cement grout installations to prevent latex migration, and 10 days at 70°F (21°C) for epoxy grouts to reach maximum chemical resistance prior to filling the water feature. Cure time can be significantly increased or decreased due to temperature and humidity.

Inspection – A swimming pool or water feature should be inspected prior to filling and then again prior to use for any non-conformities. Final grouting and sealant touch-ups should be performed during this phase. Critical areas include the sealant treatment at all penetrations and drains. The sealant should be in place and cured prior to filling the water feature to prevent any water intrusion behind the tiled system. Cleaning should also take place prior to filling the water feature to prevent any dirt, cleaners and ‘dirty’ water from entering the filtration system.

Before filling of the pool, and its subsequent provisional acceptance at substantial completion, the tile installation shall be visually inspected and sounded in the presence of the Architects and/or the Owner's representative to verify adhesion of the tile to its substrate as well as its over-all compliance with the specific requirements.

Any and all tile work found to be loose, improperly adhered, out of plane, misaligned or otherwise non-conforming shall be removed and replaced.

Protection of Waterproofing Membranes – Waterproofing membranes must be allowed to fully cure at the required temperatures as stated by the manufacturer. The membranes must be protected from UV exposure beyond the stated time period and from the elements (including rain, wind and direct sunlight). Tenting and shading the work areas for the installation and cure periods is critical to ensuring the long-term performance of the installation system.

Protection of Completed Tile and Grout Installation – The completed tile and grout installation must also be protected from construction traffic, debris from other trades and the elements until all the installation components reach their full cure. In many cases, latex fortified portland cement mortars and grouts require a minimum 14 day cure at 70°F (21°C) after the final grouting period. Epoxy adhesives and grouts require a minimum 10 day cure at 70°F (21°C) after the final grouting period. If the completed installation is exposed to the elements, it should be tented and shaded during this time frame to ensure a proper cure.

7.8 Typical Renders and Details for Swimming Pool and Water Features

Surface Preparation – LATICRETE® 3701 Fortfied Mortar Bed; or, LATICRETE 3701 Mortar Admix mixed with LATICRETE 226 Thick Bed Mortar

LATICRETE® 3701 Fortified Mortar Bed is a polymer fortified blend of carefully selected polymers, portland cement and graded aggregates. LATICRETE 3701 Fortified Mortar Bed does not require the use of latex admix. LATICRETE 3701 Forttified Maortar Bed is designed to mix with water only and provides exceptional working properties and exceptional performance characteristics.

LATICRETE 3701 Mortar Admix is a specially designed latex additive for use in cement leveling mortars and mortar beds. LATICRETE 3701 Mortar Admix is used in place of water to improve the uniformity, workability and physical properties of any mortar bed installation. Economical and versatile, LATICRETE 3701 Mortar Admix can be used for patching, leveling and fortifying mortar beds. A mortar bed mixed with LATICRETE 3701 Mortar Admix is thermal shock, chemical and frost resistant.

LATICRETE 226 Thick Bed Mortar is a factory prepared blend of high strength portland cement and graded aggregates for leveling or thick bed applications from 1/8" to 2" (3 mm to 50 mm) thick. Use with LATICRETE 3701 Mortar Admix for high strength leveling and concrete patches.

Waterproofing Membrane – LATICRETE 9235 Waterproofing Membrane or LATICRETE Hydro Ban

LATICRETE 9235 Waterproofing Membrane is a thin, flexible, load bearing, liquid applied, fabric reinforced waterproofing membranes. LATICRETE Hydro Ban is a thin, flexible, load bearing, liquid applied waterproofing membrane that does not require the use of fabric in most situations. Both LATICRETE 9235 Waterproofing Membrane and LATICRETE Hydro Ban help minimize efflorescence and deterioration of underlying assembly components by eliminating damaging water infiltration. Both membranes are applied with a paint roller or brush, are non-flammable and have no significant odor. Both LATICRETE 9235 Waterproofing Membrane and LATICRETE Hydro Ban are IAPMO and ICC approved as shower pan liners and carry an “Extra Heavy” service rating per ASTM C627(TCNA).

Consult LATICRETE Product data sheets for full installation instructions. Consult the LATICRETE website at www.laticrete.com for latest information.

Figure 7.21 – Thick Bed Floor / Waterproofing System with drain detailing.

Stain Resistant Grout – LATICRETE® SpectraLOCK® PRO Grout

LATICRETE® SpectraLOCK® PRO Grout is a chemical and stain-resistant grout for ceramic tile and stone. LATICRETE SpectraLOCK PRO Grout is ideally suited to eliminate deterioration caused by pool water chemicals an and and poor water chemistry maintenance. LATICRETE SpectraLOCK PRO Grout provides for easy cleanability and low maintenance while maintaining extremely long lasting performance.

Latex Fortified Grout – LATICRETE PermaColor Grout^

LATICRETE PermaColor Grout^ is an ideal choice for submerged installations where proper pool water chemistry is maintained continually. LATICRETE PermaColor Grout by UV light and rain, and provides a hard, durable grout joint.

Figure 7.22 – Tiled pool gooseneck gutter assembly with adhesive mortars.

7.9 Warranty

Laticrete International, Inc. offers the most comprehensive systems warranty in the tile and stone installation industry. Please refer to the LATICRETE 25 Year System Warranty (DS 025.0) in Section 12.1 for more information. Please visit www.laticrete.com for the most recent copies of these documents.

United States Patent No.: 6881768 (and other Patents).

^ United States Patent No.: 6784229 B2 (and other Patents).