How to Guide
We proudly support the following industry organizations:
MAPEI Headquarters of the Americas
1144 East Newport Center Drive
Deerfield Beach, Florida 33442
1-888-US-MAPEI (1-888-876-2734) /
(954) 246-8888
Technical Services
1-800-992-6273 (U.S. and Puerto Rico)
1-800-361-9309 (Canada)
Customer Service
1-800-42-MAPEI (1-800-426-2734)
Services in Mexico
0-1-800-MX-MAPEI (0-1-800-696-2734)
Edition Date: May 24, 2016
PR: 4127 MKT: 16-1548
For the most current BEST-BACKED
SM
product data and warranty information, visit www.mapei.com.
All Rights Reserved. Printed in the USA. © 2016 MAPEI Corporation.
SURFACE PREPARATION
• Surfaces must be structurally sound, stable, clean and free from dust, oil,
grease, paint, gypsum patch, flooring adhesive, tar, wax, sealers, curing
compounds, form release agents, laitance, loose particles and foreign
substances that could reduce or impair adhesion.
• Remove all traces of paint, loose particles, residue and cement particles
by mechanical means.
• Remove mildew by scrubbing with a mixture of 4 U.S. oz. (118 mL) of
trisodium phosphate (TSP), 1 U.S. qt. (946 mL) of liquid bleach and 3 U.S.
qts. (2,84 L) of warm water. Protect eyes and hands by wearing goggles and
water/chemical-resistant gloves. Thoroughly rinse and allow surface to dry
completely before caulking and painting.
• Vacuum out joints and wipe them clean with a damp rag.
Consult MAPEI’s Technical Services Department for installation recommendations
regarding substrates and conditions not listed.
PRODUCT APPLICATION
Read all installation instructions thoroughly before installation.
1. Tile should be firmly set before caulking. Typically, this is 24 to 48 hours
after tile installation.
2. Caulking may be done either before or after grouting.
3. For a clean, straight and neat caulk joint, mask both sides of the joint with
masking tape.
4. Keracaulk S and Keracaulk U come ready to use. Apply with a caulking
gun. Do not open cartridges until preparatory work has been completed.
5. Cut the nozzle tip to the desired bead size at a 45-degree angle.
6. Completely fill joints with sealant and smooth over with a wet, gloved
finger.
7. Excess caulk should be removed with a damp cloth before the caulk skins
over.
8. Immediately wash hands and tools with warm water and soap.
PROTECTION
1. Allow 24 hours of drying time before painting.
2. Protect from water exposure until fully cured for at least 72 hours.
Note: Large beads of caulk and cool, humid conditions will require a longer
drying time.
Refer to the SDS for specific data related to health and safety as well as product
handling.
STATEMENT OF RESPONSIBILITY
Before using, user shall determine the suitability of the product for its intended
use and user alone assumes all risks and liability whatsoever in connection
therewith. ANY CLAIM SHALL BE DEEMED WAIVED UNLESS MADE
IN WRITING TO US WITHIN FIFTEEN (15) DAYS FROM DATE IT WAS,
OR REASONABLY SHOULD HAVE BEEN, DISCOVERED.
Shelf Life and Product Characteristics*
at 73°F (23°C) and 50% relative humidity
Drying time 24 to 48 hours
Shelf life
2 years when stored in original, unopened
packaging
VOCs (Rule #1168 of
California's SCAQMD)
< 25 g per L
Colors
Available in MAPEI's palette of 40 colors (plus
Clear for Keracaulk U only), organized into 5
color collections. Refer to MAPEI's grout/caulk
color chart. Sample color chips are available
upon request.
* Cold temperature or high humidity may alter these properties.
Packaging
Size
Keracaulk S: 10.5 U.S. oz. (311 mL) tube
Keracaulk U: 10.5 U.S. oz. (311 mL) tube
Approximate Coverage** per 10.5 U.S. oz. (311 mL)
Joint Size Coverage
1/16" (1,5 mm) 48 to 50 lin. ft. (14,6 to 15,2 m)
1/8" (3 mm) 24 to 25 lin. ft. (7,32 to 7,62 m)
3/16" (4,5 mm) 15 to 17 lin. ft. (4,57 to 5,18 m)
1/4" (6 mm) 11 to 13 lin. ft. (3,35 to 3,96 m)
** Coverages shown are for estimating purposes only. Actual jobsite coverages
may vary depending on the joint size and application procedures.