SikaTile®-425 LHT Secure Set Rapid
SikaTile®-425 LHT Secure Set Rapid is a premium-grade, single-component, high-performance, polymer-modified, rapid-setting large and heavy tile mortar for interior and exterior installations of tile. This mortar has a high content of unique dry polymer, resulting in excellent adhesion to the substrate and tile. SikaTile®-425 LHT Secure Set Rapid is a fast setting product, allowing grouting in 3 hours and open for traffic in 4 – 6 hours.
- For use with ceramic tile, porcelain tile, and natural stone
- Ideal for time critical residential and commercial applications
- Superior flexibility, high strength, with rapid set time
- Allows for grouting in 3 hours and open for traffic in 4 – 6 hours
- For use with large and heavy tile and natural stone
- Rapid setting formula
- Non-slumping/non-shrinking formula eliminates tile lippage
- May be applied up to 3/4" (19 mm) thick on horizontal applications
- For interior and exterior floors and walls
- Mold and mildew resistant
Usage
SikaTile®-425 LHT Secure Set Rapid supports large and heavy tile for flat, even installations and is suitable for bonding the following types of tile and stone:- Brick and thin brick
- Cement-based precast terrazzo
- Impervious porcelain and glass tile
- Natural stone tile
- Vitreous, semi-vitreous or non-vitreous tile:
- Ceramic, mosaic, quarry, cement body tile
- Brick Masonry
- Cement Backer Board1
- Cement Mortar Beds
- Cement Plaster
- Cement Terrazzo
- Ceramic Tile and Stone
- Concrete
- Concrete Masonry
- Exterior Grade Plywood2
- Gypsum Wallboard2
- SikaLevel®
- SikaTile® Membranes
- Approved SikaLastic® Under Tile Waterproofing
2 Interior Use Only.
Advantages
- For use with ceramic tile, porcelain tile, and natural stone
- Ideal for time critical residential and commercial applications
- Superior flexibility, high strength, with rapid set time
- Allows for grouting in 3 hours and open for traffic in 4 – 6 hours
- For use with large and heavy tile and natural stone
- Rapid setting formula
- Non-slumping/non-shrinking formula eliminates tile lippage
- May be applied up to 3/4" (19 mm) thick on horizontal applications
- For interior and exterior floors and walls
- Mold and mildew resistant
Packaging
25 lb. (11.34 kg.) bag
Color
Gray and White
Product Details
ENVIRONMENTAL INFORMATION
Sika® is committed to environmental responsibility in both products produced and in manufacturing practices. Complete the LEED Product Data Request Form SikaTile.com for detailed information based on project location. Use of this product can contribute towards LEED® v3 certification:
- Up to 2 points towards MR Credit 5, Regional Materials
- Up to 1 point towards IEQ Credit 4.1, Low-Emitting Materials – Adhesives & Sealants
APPROVALS / STANDARDS
American National Standards Institute (ANSI) — ANSI A108.5, A118.4F and A118.11 of the American National Standards for the Installation of Ceramic Tile ASTM International (ASTM)
- ASTM C109 Standard Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2” or 50mm Cube Specimens)
- Resilient Floor Covering Institute - (RFCI) Recommended Work Practices for Removal of Resilient Floor Coverings
- Tile Council of North America (TCNA) - TCNA Handbook for Ceramic Tile Installation, TCNA EJ171 Movement Joint Guidelines.
- ISO 13007-2 C2FP1
Chemical Base
Portland cement, selected aggregates, water retention additives, re-dispersible polymer
Shelf Life
6 months from date of production when stored in original, sealed package
Storage Conditions
Store in undamaged, original, sealed package, in dry conditions at 73⁰ F (23⁰ C)
Slant Shear Strength
4 Week Shear Bond Strength
| Property | Test Method | Requirement | Typical Results |
| Glazed Wall Tile | A118.4 | > 300 psi | 350 - 450 |
| Porcelain Tile (4h) | A118.4F | > 50 psi | 150 - 250 |
| Porcelain Tile (28d) | A118.4 | > 200 psi | 300 - 400 |
| Quarry Tile to Plywood (28d) | A118.11 | > 150 psi | 150 - 200 |
ISO 13007 Classification
| Classification Code | Classification Requirement | Results |
| C2 (cementitious, improved adhesion) | ≥ 145 psi (1 MPa) after standard aging. Heat aging, water immersion and freeze/thaw cycles | Pass |
| F (fast setting adhesive) | ≥ 72.5 psi (0.5 MPa) for tensile adhesion strength after 6 hours, and open time after 10 min | Pass |
| P1 (normal adhesion to plywood) | ≥ 72.5 psi (0.5 MPa) | Pass |
Application
Mixing Ratio
2.5 quarts (2.4 liters) of clean potable water per 25 lb. bag
Pot Life
45 Minutes*
Open Time
10 - 20 minutes*
Cure Time
Allow 2-3* hours before grouting, 4 hours before opening to light traffic and protect from heavy or vehicular traffic for 24 hours
* Pot life, open time, and time before grouting vary based on ambient temperatures and jobsite conditions.
Applied Product Ready for Use
Grouting may begin 2 to 3 hours after installation of tile, or once tile has reached a firm set. Product curing time is affected by ambient and surface temperatures and humidity. Allow at least 4 hours before opening to light traffic and protect from heavy or vehicular traffic for 24 hours. As necessary, use plywood or other load distributing protection when moving heavy equipment across tiled assembly.
Coverage
MIXING
In a clean container, add approximately 2.5 quarts (2.4 liters) of clean potable water, then add the contents of the 25 lb. (11.34 kg) SikaTile®-425 LHT Secure Set Rapid mortar. Mix thoroughly by hand or with a slow speed mixer to a smooth, thick, trowelable consistency. No need to slake, once mixed the product is ready to use. Mortar consistency shall be such that when applied with the recommended notched trowel to the substrate, the ridges formed in the mortar do not flow or slump. During use, stir mortar mix occasionally. Do not add additional water. Do not add latex liquid additives to SikaTile®-425 LHT Secure Set Rapid.
APPLICATION
Read all installation instructions before installation. Choose a notched trowel with sufficient depth to achieve more than 80% mortar coverage and transfer to substrate and back of tile to both the tile and substrate for all interior applications, and more than 95% for exterior, commercial floor and wet applications, back-butter the tile to meet these requirements. With pressure, apply a coat of mortar by using the flat side of the trowel to key the mortar into the substrate. With the notched side of the trowel, apply additional mortar by combing it in a single direction parallel to the shortest dimension of the tile. Spread only as much mortar as can be tiled before the product skins over. Open time can vary with jobsite conditions. Set tiles firmly into the wet mortar and push the tiles back and forth in a direction perpendicular to trowel lines to collapse the mortar ridges and to help achieve maximum coverage.
MOVEMENT JOINTS:
All expansion, control, construction, cold, saw-cut, isolation, contraction, and seismic joints in the structure should continue through the tilework, including such joints at vertical surfaces, as specified per TCNA Method EJ171 or TTMAC Specification Guide 09 30 00, Detail 301MJ. Do not cover movement joints with mortar.
CLEANING OF TOOLS
Clean tools and tile with water before the material dries.
FAQ
Mortars are designed to perform in a in a wide range of environments and situations, and for a variety of tile types and sizes. Review product Technical Data Sheets or speak with Technical Services to find the right product solution.
Open time is important when installing large tile, gauged porcelain tile panels and slabs (GPTP/S) and membranes with a fleece to give proper transfer and coverage.
A118.4 is the minimum standard test that allows a mortar adhesive to bond to a porcelain tile. A118.11 is the minimum standard that allows for tile to be bonded directly over exterior-grade plywood in an interior application.
Any tile larger that 15” on one side and/or heavier than 5 lb per sq. ft is defined as an large and heavy tile (LHT). These oversized tiles demand mortars with specific bond and performance characteristics.
Medium bed is a manufacturer's termfor the allowance of tile mortar adhesive to have a maximum bond coat of ¾” thick.
The word slake means to let rest with water. When mixing standard mortar or grout with water, manufacturers recommend letting the product rest before remixing to allow the polymers to wet out. This ensures that the product performs to spec. Our products with No-Slake technology are ready to apply after the initial mix.
No. Thinset is an adhesive, not a patching or leveling compound. Thinsets are
designed to be a certain thickness and when that thickness is greater than what the thinset can handle, shrinking will occur. Use a product that is designed for patching or leveling.