Choosing the right flooring adhesive is crucial for a successful flooring installation. The wrong adhesive can lead to floors that warp, bubble, or come loose. With so many types of adhesives on the market, it can be tricky to select the best one for your flooring project. This comprehensive guide will walk you through the key factors to consider when choosing an adhesive, from substrate preparation to adhesive specifications. Follow these tips and you’ll be able to choose the perfect adhesive for a long-lasting flooring installation.
Evaluate the Subfloor
The first step in choosing the right adhesive is evaluating your subfloor, as the adhesive must be compatible with the subfloor material.
Wood Subfloors
For wood subfloors like plywood, OSB, and boards, the surface must be cleaned and made smooth. Inspect for loose boards or panels and re-nail or screw down any loose sections. Fill any cracks or holes with a polymer-modified, cement-based patching compound. Sand down high spots for a level surface. Wood floors should not have more than 3% moisture content prior to installation.
Concrete Subfloors
Concrete must be fully cured, at least 60 days old, and should have a moisture vapor emission rate of less than 3 pounds per 1,000 square feet over 24 hours. Test alkalinity, which should register between 5 and 9 on the pH scale. Remove any grease, wax, oil, or dirt. Grind down any high spots and fill low areas with a cement-based patching compound.
Existing Floor Coverings
Make sure existing flooring is well-bonded to the subfloor before applying new flooring. Ceramic, terrazzo, and resilient tile usually provide a suitable surface. Remove any loose tiles and fill depressions or cracks with floor leveler. For sheet vinyl, make sure the layers are well-adhered. Scrape up any loose edges or patches. With carpeting, remove old carpet and padding before installing the new floor.
Radiant Heat Systems
Turn off radiant heating systems for several days before and after installing over it. The subfloor should be under 85°F during installation. After flooring is installed, gradually increase heat in 5° increments.
Moisture Testing
Test moisture levels, especially for concrete subfloors. Conduct calcium chloride tests or use a relative humidity probe. High moisture levels can break the adhesive bond. Follow the flooring manufacturer’s recommendations for acceptable moisture levels and testing methods.
Pick the Right Adhesive Type
With the subfloor prepped, it’s time to select the right type of adhesive for the flooring material and installation method.
Hardwood
For solid and engineered hardwood, use a flexible wood flooring adhesive to allow for minor wood movement. Urethane adhesives provide a tenacious bond and moisture resistance. Look for a low-VOC product that meets or exceeds ASTM D3498 standards for wood flooring adhesives.
Laminate and Vinyl Plank Flooring
Vinyl plank and laminate flooring usually call for pressure-sensitive adhesives applied in a uniform grid pattern. Acrylic or latex-based adhesives allow planks to be repositioned during installation. Look for an adhesive approved by the flooring manufacturer.
Luxury Vinyl Tile (LVT)
LVT can be installed with pressure-sensitive, releasable adhesives that allow the tiles to be repositioned. For areas with heavy rolling loads or potential moisture issues, use a wet-set acrylic or urethane adhesive for permanent bonding.
Vinyl Sheet Flooring
For sheet vinyl, use a permanent pressure-sensitive acrylic adhesive for porous surfaces, or a wet-set adhesive for non-porous surfaces like concrete. Wet-set adhesives provide a superior bond.
Carpet Tiles
Carpet tiles usually employ releasable, pressure-sensitive adhesives that allow for easy repositioning and future replacement. Grid-pattern application facilitates tile alignment. Look for low-VOC, non-staining formulas.
Wall-to-Wall Carpeting
For direct-glue installation of broadloom carpeting, use a premium multipurpose carpet adhesive to bond carpet to the subfloor. Most provide a strong initial grab and long-term bond.
Ceramic, Porcelain, or Stone Tile
Use a premium polymer-modified thinset mortar adhesive for ceramic, porcelain, and natural stone tiles. White formulations allow color of grout to show through. Meet or exceed ANSI A118.4 standards for tile setting adhesives.
Consider Application Method
The adhesive application method also depends on the flooring type and subfloor conditions.
Trowel Application
Using a notched trowel, apply a thin layer of adhesive evenly over the subfloor for materials like wood, tile, and sheet vinyl. Consider a square-notched or V-notched trowel depending on flooring thickness.
Aerosol Spray
Special aerosol-spray adhesives come in portable cans for convenient application. The fine spray covers large areas quickly. Use light, even coats for materials like carpet tiles and vinyl plank.
Roll-On Application
Some liquid adhesives are applied with a paint roller for smooth, even coverage. Easy clean-up with just soap and water. Useful for flooring that requires full-spread adhesion like vinyl sheets.
Grid/Pattern Method
Some pressure-sensitive adhesives are applied in small beads in a grid pattern. The adhesive reactivates when flooring is laid over top. Allows repositioning of planks and tiles during installation.
Match Adhesive Specifications
Choosing the right specifications ensures proper bonding strength and moisture resistance. Consider factors like:
- Adhesive Type: Acrylic, urethane, epoxy each have different properties. Pick the type recommended for the flooring material.
- VOC Content: Low-VOC adhesives are better for indoor air quality. Products with 0 g/L VOCs are ideal.
- Open Time: The time window before adhesive becomes tacky after application. Long open times aid positioning.
- Cure Time: The time for adhesive to fully set and bond with the flooring. A longer cure time allows working in sections.
- Moisture Resistance: Look for “moisture resistant” labeling. Essential for concrete and below-grade applications.
- Freeze-Thaw Stability: For cold climate installations, adhesive must withstand repeated freeze-thaw cycles without breaking down.
- Shear Strength: The tensile strength of the adhesive after curing. Higher psi ratings offer a stronger bond.
- Flash Time: The recommended waiting time after applying adhesive before installing flooring. Allows evaporation of solvents.
- LEED Credits: Adhesives can contribute points to LEED green building certification. Look for LEED-compliant products.
Work Safely with Adhesives
Adhesive fumes and skin contact can be hazardous. Follow all safety precautions:
- Work in a well-ventilated area, use a fan to circulate fumes.
- Wear gloves and safety goggles to prevent skin and eye contact.
- Follow fire precautions, don’t smoke, or use near open flames.
- Dispose of adhesive cans and used trowels properly according to local regulations.
- Keep adhesive away from children and pets while working.
Prep the Flooring Material
Before starting installation, ensure the flooring materials have reached room temperature and proper moisture levels:
- Hardwood Flooring: Acclimate to interior conditions for 72 hours prior to installation.
- Vinyl Planks and Tiles: Condition in space for at least 48 hours before installing. Cut pieces to fit several hours prior.
- Ceramic Tile: Verify tiles are free of moisture and dusty residue before setting tiles.
- Carpet: Unroll, unpack, and cut carpet 12-24 hours before installation for proper conditioning.
Install Flooring Correctly
When laying flooring, follow manufacturer’s instructions for open times, flash times, and working in sections that correspond with adhesive specifications:
- Spread adhesive evenly over prepared subfloor using recommended trowel size and type.
- Allow adhesive to develop tack before laying flooring material. Avoid getting adhesive on surface.
- Lay flooring carefully within adhesive’s open time window. Periodically lift flooring to check for proper adhesive transfer.
- Roll and cross roll flooring with a 75-100 lbs roller within 30 minutes of installation to properly adhere material.
- Follow directions for flash times, cure times and when foot traffic and furnishings can be allowed on finished flooring.
With the right choice of flooring adhesive matched to your specific project needs, you can create a beautiful, long-lasting flooring installation. Evaluating the subfloor, selecting the appropriate adhesive type and specifications, safely applying the adhesive, properly conditioning the flooring, and correctly installing the flooring will ensure success. Carefully following the tips outlined above will allow you to choose the ideal adhesive for durable, high-performing floors.
Frequently Asked Questions About Choosing Flooring Adhesives
Still have questions about selecting the perfect adhesive for your flooring project? Here are answers to some frequently asked questions:
What type of flooring adhesive should I use under wood flooring?
Use a flexible, moisture-cured urethane wood flooring adhesive for a tenacious, water-resistant bond under solid or engineered hardwood flooring.
Can I use construction adhesive instead of flooring adhesive?
No, construction adhesives like Liquid Nails generally do not provide the flexibility, shear strength, or moisture resistance needed for most flooring materials. Always use an adhesive designed for the specific flooring type.
What adhesive is best for vinyl plank flooring?
Vinyl plank flooring usually requires a releasable, pressure-sensitive adhesive applied in a grid pattern which allows the planks to be repositioned during installation.
How do I know if my concrete subfloor is suitable for installing flooring?
Test concrete subfloors for proper moisture levels, alkalinity, and curing before installing flooring. Water vapor emission should not exceed 3 lbs per 1,000 square feet over 24 hours.
Can I install LVT tile over existing vinyl flooring?
Yes, luxury vinyl tile can be installed over well-bonded sheet vinyl or vinyl tile floors. Use a premium acrylic or urethane adhesive suitable for the substrate.
What glue works best for carpet tiles?
Use a releasable, pressure-sensitive acrylic latex adhesive applied in a grid pattern for carpet tiles. This allows for easy repositioning and future replacement if needed.
Is it okay to install flooring over radiant heat floors?
Yes, but the system must be turned off for several days before and after install. Gradually increase temperature in increments after flooring is installed.
What adhesive should I use for porcelain or ceramic tile?
Use a polymer-modified mortar meeting ANSI 118.4 standards for porcelain, ceramic, and natural stone tile installations. White formulations work best for lighter grout colors.
How long does flooring adhesive take to fully cure?
Cure times vary by adhesive type and range from 24 hours to 72 hours typically. Do not allow foot traffic or move heavy furniture onto flooring until adhesive has fully cured.
Conclusion
Choosing the optimal flooring adhesive does not have to be a daunting challenge. By carefully evaluating your subfloor, selecting the proper adhesive type for your specific flooring material, applying the adhesive correctly, and following all installation instructions, you can achieve a successful, long-lasting bond with your new flooring. With so many adhesive options on the market, be sure to read labels and manufacturer specifications closely. And don’t be afraid to consult with flooring and adhesive experts if you have any questions. Taking the time to choose the right adhesive will pay dividends with many years of durable and beautiful floors.