Installation Guide

ManualsBrandsBostik ManualsFlooring AdhesivesA39000

This supersedes and replaces in its entirety all previously published versions of this document.

T2070 (Last revised on 09.18.17)

KEY FEATURES

– Over 25 years of industry-

leading performance

– Moisture vapor protection

– Bostik’s Blockade™

antimicrobial protection

WOOD FLOORING URETHANE ADHESIVE AND MOISTURE VAPOR CONTROL

Bostik's BEST

DESCRIPTION

Bostik's BEST

is a high performance adhesive and moisture

control membrane. Its superior properties provide a tough,

flexible, tenacious bond to a variety of surfaces. Bostik’s BEST

high tacking formula exhibits exceptional green grab immediately

after troweling, making installation easier and more secure.

This adhesive has low VOC’s (measured per EPA Method 24) and

does NOT contain any water. Bostik's BEST

contains Bostik's

BLOCKADE™ antimicrobial protection, which inhibits the growth

of bacteria, mold, or mildew on the surface of the dried adhesive.

MOISTURE PROTECTION

Bostik’s BEST

has very low moisture vapor permeability and

is not adversely affected by moisture vapor. As a result, it will

reduce moisture vapor transmission through the concrete. When

applied as directed as a moisture vapor membrane, it will prevent

damages caused by subfloor moisture beneath dimensionally

stable, engineered wood flooring only. As a result, costly and time-

consuming concrete moisture testing is not required for engineered

hardwood flooring when the slab is properly prepared, dry to the

touch, and fully cured. For solid hardwood or bamboo on substrates

>3 lbs. or 75% RH, use Bostik’s MVP4™ prior to the application of

Bostik’s BEST

for unlimited moisture vapor protection, or use Bostik

Ultra-Set

SingleStep2™ or GreenForce

ANTIFRACTURE PERFORMANCE

Bostik's BEST

’s elastomeric characteristics establish an anti-

fracture membrane that can bridge cracks up to 1/8" (3mm) which

can occur in the substrate prior to or after installation. This superior

elasticity allows the adhesive to move with the wood as it expands

and contracts with changes in humidity and temperature over the

life of the floor.

ULTIMATE VERSATILITY

Bostik’s BEST

may be used to adhere all engineered, solid (adhesive

only), bamboo (adhesive only), cork, and parquet hardwood flooring

(adhesive only). Bostik’s BEST

may be used over all properly

prepared substrates common to hardwood flooring installations

including concrete, plywood, OSB, well bonded vinyl/VCT and

ceramic tile, cement backer board, gypsum underlayments (dry,

above-grade), cement patch/underlayments, radiant-heat

flooring, and properly prepared terrazzo. This adhesive can also be

used to install plywood as described below, as well as ceramic tile,

marble, and stone inlays for light commercial and/or residential

applications.

LEED

CONTRIBUTION

Bostik's Best

's low-VOC formulation (tested by EPA Method

24) may contribute toward LEED

credits under section EQ 4.1:

Low-Emitting Materials – Adhesives & Sealants.

DIRECTIONS FOR USE

Read and understand data sheet completely before beginning

installation. Follow industry standards and flooring manufacturer’s

recommendations for acclimation, design, layout, and application

of wood flooring material. If jobsite conditions are outside of

flooring manufacturer’s recommendations, take necessary

corrective actions. Whether the moisture content of substrate

exceeds or is within the flooring manufacturer’s recommendations,

to address current or possible future subfloor moisture, sound, and

cracks (up to 1/8"), apply Bostik’s BEST

as directed.

SURFACE PREPARATION

Surfaces must be absorptive, clean, and free from loose materials,

Summary of content (4 pages)

PAGE 1
Bostik's BEST ® WOOD FLOORING URETHANE ADHESIVE AND MOISTURE VAPOR CONTROL KEY FEATURES – Over 25 years of industryleading performance – Moisture vapor protection – Bostik’s Blockade™ antimicrobial protection DESCRIPTION Bostik's BEST® is a high performance adhesive and moisture control membrane. Its superior properties provide a tough, flexible, tenacious bond to a variety of surfaces.
PAGE 2
PLYWOOD OVER CONCRETE: Score 4' x 4' or 2' x 8' sheets of 3/4" exterior-grade plywood on the backside every 8" to 10" by using a circular saw and cutting one-half the thickness of the plywood; “scoring or kerfing” takes the tension out of the plywood and helps to prevent possible warping or curling. Apply adhesive to substrate and then set plywood into the wet adhesive. Allow the adhesive to fully cure before nailing or using Bostik’s BEST® adhesive to install flooring.
PAGE 3
• • • • • • • hard (not dusty/powdery), with a minimum compressive strength > 2,000 psi for engineered hardwood installations, or minimum compressive strength > 2,500 psi for solid hardwood installations. Please refer to flooring manufacturer’s recommendations and NWFA’s specifications for proper acclimation, verification of moisture content of flooring with a moisture meter, and expansion relief around perimeter throughout installation.
PAGE 4
TROWEL SELECTION In order to form a membrane that functions properly for moisture vapor protection, the right trowel needs to be selected to achieve both 100% coverage of the substrate and 100% transfer to the back of the flooring. Jobsite conditions, profile of the substrate, depth of back channeling in the flooring, and other factors affect the amount of adhesive that must be applied to achieve proper coverage and transfer.