Products : Adhesives : Wood Adhesive : Wood UR4 Ultimate Adhesive

Wood UR4 Ultimate Adhesive

Wood UR4 is a supreme handling urethane adhesive that does the job of four products, all in one application. Ideal for the most critical jobs, this 4-in-1 product works as an adhesive, concrete moisture control, sound reducer and crack isolation membrane. Additionally, WOOD UR4 is one of the most elastic urethanes on the market, allowing for naturally occurring expansion and contraction of wood.

Suitable as an adhesive

  • Solid Wood Plank
  • Engineered Wood Plank
  • Bamboo (not strand woven)
  • Ceramic Tile
  • Natural Stone Inlays
  • Plywood Panels [for nail down/double bond installations]
  • Underlayments [Recycled rubber/cork]
  WHERE TO BUY Not all products are sold at all stores. Please call the distributor to ensure product availability.
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Key Features

Features/Benefits of Product in the Installation

  • 4-in-1 technology reduces install time and eliminates need for multiple products
  • Single application moisture barrier and adhesive reduces material and labor costs.
  • Sound reduction and crack bridging capabilities for the most challenging applications
  • Highly elastic formula allows for expansion and contraction without damaging adhesive


Applicable Standards

  • NWFA / National Wood Flooring Association – Wood Flooring Installation Guidelines
  • ASTM F710 Standard Practice for Preparing Concrete Floors to Receive Resilient Flooring
  • ASTM E96 Standard Test Methods for Water Vapor Transmission of Materials
  • ASTM E492 Standard Test Method for Laboratory Measurement of Impact Sound Transmission
  • ASTM E90 Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements
  • ASTM E2179 Standard Test Method for Laboratory Measurement of the Effectiveness of Floor Coverings in Reducing Impact Sound Transmission Through Concrete Floors
  • ICRI / International Concrete Institute
  • ASTM F2170 Relative Humidity in Concrete Floor Slabs – using in situ Probes
  • ASTM F1869 Measuring Moisture Vapor Emission Rate of Concrete Subfloor Using Anhydrous Calcium Chloride
  • ASTM F2419 Standard Practice of Thick Poured Gypsum Concrete Underlayments and Preparation of the Surface

Conformance to Building Codes

Installation must comply with the requirements of all applicable local, state and federal code jurisdictions.

Environmental Consideration

Custom® Building Products is committed to environmental responsibility in both products produced and in manufacturing practices. Use of this product may contribute to LEED® certification.

Suitable Substrates

  • Cement-based self-leveling underlayment and patching compounds
  • Cement/epoxy terrazzo
  • Concrete (industry approved) - at least 14 days old with an appropriate moisture vapor barrier properly installed under slab
  • Epoxy Coatings
  • Existing well bonded floor coverings
  • Plywood and other approved wood substrates
  • Properly prepared primed/sealed gypsum underlayment per ASTM F2419
  • Radiant heated floors (temperature should not exceed 85° F)

* All surfaces / substrates above require proper surface preparation

Acceptable Substrate Conditions

  • RH – ≤90 % / ASTM F2170 Relative Humidity in Concrete Floor Slabs - situ Probes Vapor Emission Rate – See wood flooring manufacture for product limitations and requirements
  • MVER - ≤15 lbs / ASTM F1869 Measuring Moisture Vapor Emission Rate of Concrete Subfloor Using
  • pH [Substrate] – up to 12


General Surface Prep

All surfaces must be structurally sound, without excessive deflection, clean, dry and free from contaminants that would prevent or inhibit adhesion bonding. Concrete and cement-based underlayment/patching compounds used to repair flatness deviations must be fully cured and not exhibit signs of moisture or hydrostatic conditions/issues.

Concrete substrates must have porosity/absorption as outlined by ASTM F3191 Field Determination of Substrate Water Absorption, a droplet of water must absorb into concrete within 1 minute. Concrete surfaces must meet a #1-3 CSP/Concrete Surface Profile (not polished/reflective) as defined by ICRI/International Concrete Repair Institute’s Guideline No. 03732. Substrates should be free of laitance, contaminants, surface/dissipating curing compounds. To remove curing compounds, construction debris, open up non absorptive concrete substrates, shot-blasting and/or diamond grinding methods are best methods to prepare and clean when and where necessary.

All surfaces must be flat, sound and stable. Floor Flatness requirements of 3/16” allowable variation in 10 ft. apply and/or per wood manufacture and NWFA Installation Guidelines.

Any sources of moisture are to be limited to initial concrete placement and not from sources such as water intrusion or from a lack of an effective vapor retarder/barrier under concrete slab. Substrate must be prepared per ASTM F710 standards.

It is the responsibility of the installer to determine the suitability of the substrate and any required preparation work necessary to ensure a successful installation.

Assembly mockups will determine suitability for these conditions on specific projects. Contact CUSTOM Technical Services for product information (800) 282-8786.

Fill all surface cracks, grooves, depressions, control joints and non-moving joints According to ASTM F710. Contaminants or curing compounds should be mechanically removed before installation.

Concrete must be free of efflorescence and hydrostatic pressure conditions. All concrete surfaces must have a minimum tensile strength in excess of 200 psi (1.4 n/mm²). HVAC must be operational between 60-95°F/30-65% relative humidity for ambient conditions a minimum of 72 hours prior to installation enabling the substrate and adhesive to be properly acclimated. Consult the flooring manufacture for site conditioning requirements and acclimation requirements of their materials. Large temperature and relative humidity discrepancy will affect the working time of the adhesive. Disable radiant system 24 hours prior, during and after installation – Follow radiant system manufacture’s instruction for start-up procedures.

Limitations to the Product

IMPORTANT NOTE: Install flooring in areas suitable per wood flooring manufactures written instructions.

  • For interior use only
  • Do not use when ambient and/or substrate temperature is below 50° F (10° C) or above 95° F (35° C) or when condensation exists 
  • Do Not install over surfaces with condensation or standing water
  • Not for use in areas subject to hydrostatic moisture conditions
  • Concrete substrate temperatures must be above dew point/condensation
  • Not for use as a moisture mitigation system under any other flooring types [see CustomTECH™ MVC]
  • Not for use with solid vinyl, vinyl backed carpet flooring
  • Existing adhesive must be removed to an embedded residue with no surface trowel ridges
  • Do not install over treated plywood
  • Do not dilute with water, solvents or any chemicals

Cleaning of equipment

Consult the wood manufacture for cleaning wood finish surface instructions. To remove cured adhesive from prefinished flooring, use a citrus cleaner or mineral spirits. Apply the adhesive remover to the affected area with a non-abrasive towel and allow to sit for 5-10 minutes to soften the adhesive. Then buff the adhesive off with the non-abrasive towel. Use personal protective equipment (chemical resistant gloves/ goggles/clothing). Without direct contact, remove spilled or excess product and placed in suitable sealed container. Dispose of excess product and container in accordance with applicable environmental regulations.

Product Maintenance

Follow wood flooring manufacturers written instructions for proper maintenance, chemicals and techniques.

Properly installed product requires no special maintenance, see flooring manufacture for service and maintenance requirements.

Warranty Information

Product Warranty

  • 2 Years – Product only, unopened and properly stored.
  • 15 Year System – CUSTOM Adhesive and CustomTECH Floor Preparation Systems.
  • FLOOR-MATCH Warranty – CUSTOM Adhesives & CustomTECH Floor Preparation Products/Systems are warranted equal to the Flooring manufacturer’s warranty term up to LIFETIME. *See CUSTOM FLOOR-MATCH Warranty, separate document.

Coverage Chart



Chart for estimating purposes. Coverage may vary based on installation practices and jobsite conditions. For more sizes, use the material calculator at or contact CUSTOM Technical Services at 800-282-8786.

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