Underlay-RS
RAPID SET PATCHING &
UNDERLAYMENT COMPOUND

DESCRIPTION:
Underlay-RS is a trowel grade polymer modified underlayment formulated to provide a uniform sub-surface suitable to receive a finished overlay in 3-4 hours (depending on climatic conditions). Underlay-RS also contains fungicides to inhibit the growth of mold and mildew.

USE:
A composition designed to underlay and provide an acceptable surface for various floor coverings such as resilient tile, carpet, ceramic or quarry tile, stone and vinyl sheeting. Underlay-RS is also designed to provide slope for drainage or for repairing concrete surfaces.

ADVANTAGES:
• Easy to install by screed or trowel.
• Excellent bond to concrete, wood & metal with minimum preparation.
• Cures in 3-4 hours.
• Resistant to mold and mildew.
• Crack resistant and fire retardant.
• Good thermal and acoustical insulating properties.
• Trowels to a smooth and uniform finish.
• May be installed from 0" to 3". Consult manufacturer for elevations over 3" thick.

LIMITATIONS:
• Additional sand or rock should not be added to the mix.
• Powder should not be exposed to moisture prior to application.
• Not intended as a finished surface.

CONSIDERATIONS FOR INSTALLATION:
When covering wood sheathing, use stapled expanded metal lath.
Concrete should be free of dirt and laitence.
Heavier fills (over 11/2") may produce minor hairline cracks. This will not affect performance of the product.
Consult Mer-Krete for exterior use

INSTALLATION:
Underlay-RS should be mixed as recommended by the manufacturer. Underlayment can be installed from the “needed thickness” down to a feather-edge. It can be installed over most clean, dry subsurfaces, and can normally be covered or used within 3-4 hours for foot traffic and 6-8 hours for heavy loads.

AVAILABILITY:
It is recommended that trained contractors install this product. Contact factory for an installer located nearest you.

PHYSICAL & TECHNICAL DATA:
Weight: 1.2 p.s.f. at 1/8"
Fire Rating: Fire retardant
(FTMS 105a method 6411)
Indentation:
(MIL-D-3135d) < 3%
Adhesion to Concrete:
(In Shear) > 550 p.s.i.
Water Absorption:
(FTMS 501a method 7511) < 2.5%
Compressive Strength:
28 Days > 3,500 p.s.i.

TECHNICAL ASSISTANCE:
Specification assistance is highly recommended prior to a proposed installation. Contact any Mer-Krete representative for recommendations.

WARRANTY:
Products are warranted to be free from manufacturing defects. Because specific installations are beyond our control, we assume no liability of any kind beyond the purchase price. Mer-Krete will replace any material that does not conform to our standards or will refund the purchase price within 6 months of the purchase.