Technical Advisory

This Technical Advisory deals with TCNA methods for Pools, Water Features, Tubs and Fountains

POOLS AND WATER FEATURES (Ceramic, Porcelain and Glass Tile) - pages 183 – 186

This section has changed in many ways. Method P601 has been split into the following two methods:

P601MB
This is now the “mortar bed” version of the method. The details have been improved to reflect mortar bed detailing at the coping and base with several cove base options and coping / decking profiles. More detail is provided in the section; “Preparation by other trades, which includes recommendations for soil reports, engineering analysis, etc… to meet the requirements of ANSI/ APSP (Association of Pool and Spa Professionals). Another important note that appears within the method references ongoing pool water chemistry and balance. In addition, minimum cure times are acknowledged as a critical item to consult with the installation materials manufacturer. Weather protection is also mentioned as a concern during the surface preparation, installation and cure periods. An optional surface applied waterproofing membrane can be inserted into this method. The use of heavily pigmented cementitious grouts are discouraged (primarily blue, green and red). A much more comprehensive section on movement joints is also included in the method requiring more frequent placement of movement joints.
P601TB
This is now the “thin-bed” version of the method. The details have been improved to reflect detailing at the coping/decking and cove base areas.
An optional waterproofing membrane can be inserted into this method. This method can be utilized if the concrete / shotcrete tank meets 1/8” in 10’ and 1/16” in 1’ finish tolerance and has a concrete surface profile (CSP) of 3 or better. If the concrete / shotcrete cannot meet this criterion, method P601MB should be used. The same notes that pertain to water chemistry and balance, soil reports, engineering analysis, minimum cure times of installation materials, weather protection, movement joints, etc… are also part of this method.

A new method appears in this section:
P602
This method should be utilized when the concrete / shotcrete / gunite tanks are not watertight. They can be made watertight with a “cementitious waterproofing layer” applied to the concrete shell. It is important to note that this is not an ANSI A118.10 compliant membrane. These products are produced by Xypex, Aquafin, etc… The cementitious waterproofing membrane may require additional surface preparation steps prior to applying the leveling layers (e.g. power washing).
The characteristics of the cementitious waterproofing are; “recommended by manufacturer for use in positive and negative hydrostatic pressure applications and swimming pools. Must be able to support the weight of the bonded mortar bed and tile assembly; consult manufacturer for application suitability”.
The cementitious waterproofing must make the pool tank waterproof. A flood test should be performed after the cementitious waterproofing is applied and cured per manufacturer’s directions. An optional surface applied ANSI A118.10 compliant waterproofing membrane can then be applied over the cured leveling mortars. The same notes that pertain to water chemistry and balance, soil reports, engineering analysis, minimum cure times of installation materials, weather protection, movement joints, etc… are also part of this method. Compatibility issues could arise with certain cementitious waterproofing products. In order to avoid conflicts; it is best to secure a letter of compatibility from the cementitious waterproofing manufacturer to ensure that the desired performance is achieved. We are already noticing a trend to recommending this method from several of the glass tile manufacturer’s. Bear in mind that many glass tile manufacturers do not recommend the use of a waterproofing membrane directly under the glass tile finish. Therefore, this method reconciles the need for tanks / projects that require waterproofing and the glass tile manufacturer’s restriction on the placement of membranes directly under their product.
TILE TUBS, FOUNTAINS, AND POOLS (Ceramic, Porcelain and Glass Tile) – page 187
This method has remained essentially the same when compared to previous versions. However, the term “curbs” has been dropped from the title and replaced with “pools”. The “pre-formed curb” detail previously included in this sections has been relocated to the section entitled “common shower configurations” on page 170.

In the future we will discuss the stone methods. Please let me know if you have any questions or concerns.
Arthur Mintie
Technical Services Director 
amintie@laticrete.com
Tel. +1.203.393.0010 ext. 326

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Technical Info - new additions to the 2011 TCNA Handbook

This week’s Technical Advisory deals with one of the unique new additions to the 2011 TCNA Handbook – specific installation methods that pertain to the installation of dimensional stone.

Recall that “stone” in the 2011 TCNA Handbook is defined as:

“Natural stone tile, also called dimension stone, is stone that has been harvested from its in-situ position in the Earth and cut and machined into tiles without altering the natural fabric of the material. Dimension stone has a nominal thickness of less than ≤” (19mm) and does not have any facial dimension greater than 2’ (610mm). Agglomerates and other engineered products do not meet this definition and therefore are excluded. Natural stone tiles that meet the definition but not the dimensional requirements are also excluded.” - 2011 TCNA Manual – Natural Stone Tile Selection and Installation Guide page 13.

For a refresher on natural stone tile characteristics and installation tips, reference the Natural Stone Tile Selection and Installation Guide located on pages 13-17 of the 2011 TCNA Handbook.

A note of importance contained within the Natural Stone Tile Selection and Installation Guide concerns “fiberglass mesh reinforced stone”. This note can be used to back up our position on the use of epoxy adhesive with stones backed with epoxy or polyester. The note states: “Many stone products have a mesh reinforcement adhered to the back surface of the tile. The adhesive used to attach the mesh is not standardized, but is commonly an epoxy or polyester-based adhesive that Portland cement mortars will not reliably bond to. Such reinforced stone tiles require epoxy bonding mortar.” An exclusion to this caveat is a specific stone / backing that has been tested and approved to be used with a latex fortified Portland cement based adhesive.

Another item that is need of clarification is the deflection criterion associated with stone installations over floors. The Marble Institute of America requires the following deflection criteria (MIA Design Manual):

Concrete slabs – not to exceed L/360
Plywood / Wood Framed Constructs – not to exceed L/720

Bear in mind that LATICRETE has established a deflection criterion not to exceed L/480 under total anticipated load for “stone” installations for both walls and floors (except when building codes take precedence). This LATICRETE requirement covers both dimensional stone as defined by the TCNA (above) and engineered stones. In addition, the L/480 criterion takes into account the variability in stone hardness and flexural strengths. Many stones may not have the flexural strength / integrity to be installed on slabs that meet L/360 deflection criteria. Therefore, LATICRETE’s more rigid requirement of L/480 covers the instances where these conditions may apply.

Also, it is important to note that all of the thin-bed stone installation methods require a tighter substrate surface tolerance of 1/8” in 10’ from the required plane when measured from the high points in the substrate surface.

EXTERIOR FLOORS – pages 198 - 205

Exterior Floors – (Stone) - pages 198–200
Exterior Roof / Deck Floors (Stone) – pages 201-203
Exterior Balcony / Deck Floors (Stone) – pages 204-205

A simple concept to keep in mind is that all of the exterior floor methods that apply to ceramic tile also apply to stone applications. There are a total of 5 methods that cover the three exterior applications under EXTERIOR Floors. This will not be the case with the INTERIOR Floor methods.

INTERIOR FLOORS – pages 206 – 230

Interior Floors Over Concrete – (Stone) – pages 206 – 221
Interior Floors with Radiant Heat Over Concrete – (Stone) – pages 222 – 225
Interior Floors with Radiant Heat Over Wood – (Stone) – pages 226 – 227
Interior Floors Over Wood – (Stone) – pages 228 – 230

Most of the common installation methods that apply to ceramic tile applications are covered in the stone section. Chemical resistant installations and methods that utilize organic adhesive are not suitable to receive stone as a finish and are therefore excluded.

Stone installation methods over wood framing are limited. There are 3 methods in the handbook over wood frame construction:
RH141
F141
F250 (note that this method erroneously states L/360 maximum allowable deflection, it should be L/720)

However, method F250 allows for the use of various backer board types as the underlayment in addition to multiple combinations of plywood underlayment / backer board types.

Some common notes / requirements for the stone methods are as follows:

The stone methods factor in an additional 2lbs. weight per sf when compared to the ceramic tile details.
Consider unsanded grout for soft or semi-soft stones such as limestone, travertine, marble, onyx, or similar.
Cementitious Bond Coat – use white (colored adhesive mortar) for light colored marble, limestone, and other stones where staining or darkening from grey setting materials is possible.

Next week we will discuss vertical stone installation methods. Please let me know if you have any questions or concerns.

Arthur Mintie
Laticrete International

Technical Services Director
amintie@laticrete.com