Removing Stubborn Adhesive from Concrete Floors: Techniques & Products

The removal of adhesives or mortar from a floor can be a challenging process. Commercial carpet and vinyl tile flooring are mainly installed using an adhesive. Ceramic and porcelain tile uses a cement base mortar to develop a stable, void free substrate for the tile to rest on and develop a strong bond to the concrete substrate.

All removal processes need to start with knowing what the ending result will be. Will the floor be polished, or coated with a resinous or mortar system, or have vinyl tile be installed? Knowing what the final floor system will be will help in deciding which removal process should be selected.

The reason to have a good understanding of the final flooring type, they all require a certain surface profile to provide the highest level of bond. The surface profile needed for a mortar system is much different than a thin mil resinous coating. Selecting an adhesive removal process that has a negative impact on the substrate might not be the best selection if a thin mil coating will be the final flooring system.

Types of Adhesives

• Polyurethane-based: These adhesives are common with wood flooring applications but are also used with other flooring installations. They form a chemical bond with wood cells and with the concrete below flooring.
• Acrylic-based: Acrylic adhesives are resin-based and are strong and efficient. They are most widely used with tile, stone, and LVT/vinyl products.
• Water-based: These adhesives are generally lower in VOC content and are therefore slightly better for both the interior and overall environment. They are also more of a “green adhesive” to use.
• Pressure-sensitive: Suitable for LVP flooring.
• Hard-set: Suitable for LVP flooring.

Adhesive Removal Methods

• Mechanical:
  • Scrapers
    • Tooling
      • Blade to “pop up” the material.
      • Multiple widths
    • Large and small models.
    • Ride-on models.
      • Excessive cost
      • Very efficient
      • Low operator fatigue
      • Heavy
    • Manually push models.
      • Very reasonable in cost
        • Purchase
          • Niagara Machine
        • Rent
          • Sunbelt Rentals
      • Great for smaller projects
      • Can be fatiguing to use.
      • Two workers can carry up/downstairs.
      • Can be taken apart for ease of transportation.
  • Grinders
    • Proper diamond tooling needed.
    • Pros:
      • Effective on thick layers
      • No drying time from water used to rinse after using a chemical stripper.
      • Ride-on equipment available. Reduces fatigue.
      • Remote controlled equipment available.
      • Propane and electric power equipment available.
      • Multiple size equipment suited for any project.
      • Grinders can not only be used for removal but also provide the final surface profile.
    • Cons:
      • Dust containment will be needed when grinding.
      • Noisy
      • Equipment can be heavy to move.
      • Equipment is expensive to buy.
        • Sunbelt Rentalshas equipment for rent.
      • Equipment training is needed.
        • Purchase: Niagara Machinehas Field Reps capable of training.
        • Rental: Sunbelt Rentals trains rental customers on-site or at their facility.
    • Proper tooling needs to be selected.
      • Scraper
        • Blade width and style needs to be decided.
        • Niagara Machine carries all styles.
      • Grinder
        • Tooling type needs to be figured out.
        • Niagara Machinecarries styles for different results.
• Chemical Strippers:
  • Liquid
  • Pros:
    • Lower cost.
    • Can dissolve tough residues.
  • Cons:
    • Safety precautions
    • Dwell time needed to break down the adhesive.
    • May require multiple applications depending on how thick the adhesive is.

Matching Technique to Adhesive Type

When selecting the removal process, always keep in mind what the surface profile of the final flooring needs to be. Choose the least intrusive method based on efficiency and environment.

Thin set (cement based leveling mortar):

• Responds well to mechanical methods.
• Contact us for Scarifiers and Grinders
• Contact us for Scrapers, Grinders and Scarifiers
• A combination approach.
  • Thickness and material composition dependent.
  • Scrape the majority.
• OR
  
  • Scarify the majority.
  • Grind the remaining.

Mastic:

• Grinder
  • Mastic removal tooling
    • Mastic type dependent
      • Hardness
      • Thickness
    • Contact Niagara Machine for the right Tooling.
• May need chemical strippers.
  • Thickness and type.
  • Safety precautions are crucial.

Carpet Glue:

• Type varies.
• Test patches are recommended for the best approach.

The Role of Surface Prep

The role the final surface profile takes on is based on the flooring system that will be installed. There are systems that only require a clean, durable surface. Others might need a rough, coarse surface.

A primer is the material in the system developing the bond to the substrate. Primers can be thin or thick. Generally, the lower the viscosity the primer, the less aggressive the surface profile needs to be. There are acrylic primers that call out for a clean, open, and smooth surface profile. When selecting a sanded epoxy primer usually for a self-leveling overlay, the substrate should be clean but rough. A cement-based overlay is applied at a minimum thickness of ¼” but typically greater than 3/8”. That is why sanded epoxy is used as the primer. This offers the best surface for it to bond to.

Safety & Environmental Considerations

No matter which removal system is used, personal and environmental safety should be in the plan. Keeping everyone safe should be at the top of the list.

Personal Protection Equipment (PPE) needs to be on every project no matter what the task will be. When working with any chemical, eye, foot and hand protection is imperative. Splash goggles protect your eyes from harmful liquids. Anyone that has worn them will tell you they can be cumbersome and uncomfortable. Safety glasses will help but will not protect you if there is a splash and the liquid goes airborne.

Gloves should be worn on every construction project. Leather gloves are great to protect from abrasions, cuts, and light impact. When using a mechanical removal method, leather is the perfect material. Leather will absorb and retain liquids. This is not ideal when working with chemicals. The type of chemical resistant glove must be waterproof and made from a chemical resistant material. I suggest selecting one that is also cut proof. When using chemicals there will be times when there is an opportunity to cut them.

Foot protection should always be given consideration. On non-chemical related projects, leather boots are the norm. On industrial sites, leather steel toe boots will be needed. Chemical resistant rubber boots are best when using chemical strippers.

Airborne fumes or particulates need to be considered. When dry grinding, dust will be generated. Although the grinder will be hooked up to HEPA rated vac as the first line of protection, some dust will still become airborne. Wearing a dust mask will ensure the remaining dust will not be inhaled while working.

Chemical produced fumes will require a more substantial piece of PPE. Cartridge type respirators will be used in this situation. The filter cartridge can be switched out according to the chemical type. But before you try to wear a respirator all day, you should get professionally evaluated to decide how long you can safely wear one. If you have had any lung issues in the past such as pneumonia, the time you can wear one will be shortened.

Once the work has been performed, disposal of the debris will need to be taken care of. With dust, the dust extractor should be using a continuous bag system such as DiamaPro Infinity Bags. These bags can be safely discarded once filled. Chemicals are a different story. The debris removed from the floor could be considered hazardous waste. Landfills are regulated by EPA, State and Federal laws and might have regulations in-place that must be followed. Check with the landfill you will be using before trying to dispose of the material.

Conclusion

There is much more to adhesive removal than hand scraping it from the floor. The type of adhesive you have, the method that best suites the project, and the number of square feet you have are all factors. It is important to select a method that fits the project and your abilities.

At Niagara, we have equipment to fit any project. Contact us to receive excellent customer service and trained field representatives to help you be successful.