Installing Large Format Thin Porcelain Panels

One of the hottest trends in the tile industry is the use of “large format thin porcelain bodied panels”. Due to the lightweight and versatile nature of this product type, project design professionals are demanding this product for many applications where traditional porcelain tile and stone would have been utilized. In order to completely benefit from the aesthetically pleasing nature of these finish types, unique installation techniques are required.

Thin porcelain panels range in thickness from 3mm (1/8”) to 7mm (5/16”) and can have facial dimensions up to 244cm (8 feet). Many of these panel types are manufactured with a resin or mesh backing. Undoubtedly, the resin or mesh backing provides stability to the thin porcelain panels. Many of the manufacturers of these slim porcelain panel products are suggesting that their products can be used for interior vertical applications and limited interior floor applications. Consult with the thin porcelain panel manufacturer for their recommendation on which specific panel type and thickness is suitable for a specific application. Note that not all thicknesses in a manufacturer’s product range are suitable for all applications. Exterior applications and demanding commercial floor applications may require the use of a specific manufacturer’s porcelain panel (type and thickness) that has been rated for the application and area of use.

Special installation techniques are required for successfully installing thin-body porcelain panels. For example, using a glass installer’s “vacuum suction cups” and / or “installation frames” can facilitate easier handling and placing of the panels and reduce the chance of cracking them during handling and installation. Unique rail cutter’s specially designed to cut large panels can also help installer’s execute the installation quickly and effectively. Consult the thin porcelain panel manufacturer before selection and installation to determine the porcelain panel’s suitability for the intended area of use and the specified project. Most of the thinner panel types (3mm thick) are suitable for interior wall and limited residential floor applications only.

SUBSTRATE PREPARATION:
The main challenge for installers is to make sure that the substrate is extremely flat, so as to achieve the required coverage. Floor installations of thin-body porcelain panels are only recommended over interior concrete floor slabs (and approved existing interior ceramic tile over concrete) that meet the maximum allowable deflection standard of L/360 under total anticipated load. Floor substrates for the installation of thin-body porcelain veneer panels must be prepared to a Floor Flatness (FF) of 50. Maximum variation in the substrate is not to exceed 3mm in 3m (1/8” in 10’) from the required plane, and no more than1.5mm
in 30cm (1/16” in 12”) when measured from high points.

Typical interior wall substrates are concrete, concrete block and cement backer board. Typically, polymer fortified thick bed mortars and / or self-leveling underlayment’s can be used to properly prepare a substrate prior to the installation of these thin
Porcelain panels. It cannot be stressed enough; the flatter and smoother the substrate is, the easier the installation will be.
INTERIOR APPLICATIONS:
Walls and limited floor applications based on porcelain panel manufacturer’s recommendations can be installed with high strength polymer fortified multipurpose thin set mortar, modified epoxy adhesive or epoxy adhesive mortars.

EXTERIOR FACADES (based on porcelain panel manufacturer’s recommendations):
In some cases, requests have been made to use thin profile porcelain panels on exterior applications. Please note that for exterior veneer installations, the thickness of the panels can be a concern. The 2012 International Building Code (IBC)-Chapter 14 –Exterior Walls -requires that “adhered veneer finish types” (which include ceramic and porcelain tiles) be a minimum of 6mm (¼”) thickness for use as exterior cladding. In addition, facial size dimensions can also be a factor.

For porcelain tile, the 2012 IBC [Section 1405.10.2] requires that exterior adhered porcelain tile be a maximum of 610mm (24”) in any face dimension nor more than 0.28m2 (3 square feet) in total face area and shall not weigh more than 0.43 kN/m2 (9 lbs. per s.f.).

Therefore, the project Architect or Engineer will have to gain code approval for the use of a thinner and larger format porcelain panel finish material for use in this application. Typically a high strength polymer fortified multipurpose thin set mortar can be used for these applications upon code approval.

In addition, exterior façade installations should be waterproofed to help prevent the infiltration of water into the structure and to protect building elements from corrosion.
Use an ANSI A118.10 OR EN14891 compliant waterproofing membrane that is compatible with the adhesives and mortars used for these installations.

NOTES:
Obtaining complete mortar coverage between the porcelain panel and the substrate
(100%) is absolutely essential to the long term performance of the porcelain panels. Apply notched coats of the thin-set mortar to BOTH the back of the panel and the substrate.
Typically, the trowel ridges are applied in straight lines and should be parallel to each other when placed (unless otherwise directed by porcelain panel manufacturer). Do not allow the mortar to dry or skin over during the installation process. Care must also be taken when removing a panel to inspect the thin set mortar coverage during the installation process and while the mortar is still wet to avoid damaging the thin porcelain panels during this process.

The use of hand held “vibrating” pads can assist in properly bedding the panels and achieving maximum adhesive mortar coverage. Allow a minimum of 72 hours for cure time at 21 ̊C (70 ̊F) prior to exposing floor installations of thin-body porcelain panels to light foot traffic only. Regardless of whether rapid or normal setting thin set / medium bed mortars are used, floors typically need to be protected from heavy traffic, lifts for at least 7 days at 21 ̊C (70°F). Full cure typically occurs in 28 days at 21 ̊C (70°F). However, cooler temperatures (and other climatic conditions) and the size of the porcelain panels can impact the cure rates.

In addition, anytime heavy lifts or other equipment is exposed to the floor, protection of the tile should be put into place.
It is important to note that the above cure rates are typical, but can be affected by many variables. Consult with the thin porcelain panel manufacturer for their suggestions on cure rates, time to traffic and protection of newly installed projects.
Using mechanical edge-leveling systems for floor applications (e.g. Tuscan Leveling System) can help reduce lippage and achieve complete coverage beneath the porcelain panels; especially at the edges and corners.

Bonding issues of the resin or mesh backing to the thin-body porcelain panels (or any tile or stone) is outside of the control of the adhesive mortar manufacturer and is an issue of which the tile manufacturer is responsible.

GROUTING:
Since the panels are so thin, extra attention must be given to “clean out” any adhesive mortar left in the joints during the installation in order to facilitate grouting, and the acceptance of enough grout within the grout joint. In most cases, half the depth of the grout joint should be available to receive the grout. For 3mm (1/8”) thick porcelain tile that would be only 1.5mm (1/16”). This may not be enough to allow the grout to remain in place. Therefore, the entire depth of the panel should be free of adhesive in the joints to receive the grout. Typically, either epoxy or polymer fortified cement based grouts are used for interior applications.

MOVEMENT JOINTS:
Joints scheduled to act as movement joints should also be cleaned out of all adhesive mortar and grout in order to receive bond breaker tape and the suitable sealant so as to allow the movement joint to function correctly. Use a suitable flexible sealant to treat the movement joints. Follow standard industry guidelines for movement joints in accord with Tile Council of North America’s movement joint details and information -EJ-171.

By following the application instructions of thin porcelain panel manufacturer’s and the above principles, a successful installation can be achieved. Consult with the project specifications and an installation materials manufacturer familiar with these unique applications for a completely compatible and warranted system that will provide years of beauty and performance.

By Arthur Mintie
Director, Technical Services
LATICRETE International, Inc.