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What to Use Over Old Asphalt Adhesive
Flooring FAQs - What to Use Over Old Asphalt Adhesive
Can adhesives and moisture barriers be used over old black cutback asphalt-based adhesive?
Hi Bob,
I have a customer that wants to glue down Bellawood Brazilian Cherry over black adhesive that was used 50 years ago under 9" x 9" linoleum tiles. Will the MVP adhere to that? The entire floor is completely covered. There is no concrete exposed. Could that black stuff act as a moisture vapor barrier and then just use BBA as an adhesive to that?
Thanks
Dan
Hi Dan,
The black glue you refer to is called "Cutback". It is a black asphalt-based adhesive frequently used in the past to install vinyl asbestos tile, asphalt tile and vinyl composition tile often containing asbestos. Today, most adhesives are not compatible with cutback because it is an oil based product. As such, adhesive manufacturers view all old adhesives as contaminates. Therefore it is necessary to remove or encapsulate the cutback residue before installing floor coverings since the chemicals in cutback can bleed through standard patching or leveling compounds and negatively react with the adhesive and discolor the flooring.
If the installation is over a wood subfloor, the easiest way to remedy cutback is to cover the entire floor with 2 layers of felt paper and 1 layer of plywood underlayment and then install the new floor covering over the new plywood. However, if your goal is to completely *remove the adhesive from the building then the wood subfloor with the flooring must be removed and new plywood underlayment installed.
For concrete substrates, you can also build a floating plywood subfloor system or if you prefer to remove the cutback residue, do so mechanically rather than with chemical adhesive removers. Residue from chemical adhesive removers will interfere with any new glue-bond. Use the wet-scraping method as outlined in the RFCI "Recommended Work Practices for the Removal of Resilient Floor Coverings". A copy of this RFCI can be found on our website. Procedures involve using (1 oz. specified liquid dishwashing detergent to one gallon of water, scrapers, protective clothing, respirator and a Hepa type vacuum) Do not sand, grind or blast this residue as the airborne dust may contain asbestos. Wet scrape the floor as much as you can so that the cutback residue is nothing more than a thin transparent stain. Allow adequate time for the concrete surface to dry and then apply an approved underlayment or patching compound such as ARDEX SD-F or Mapei Ultraplan. Be sure the product is approved for use over cutback residue. Keep in mind a primer may be required before using the leveling compound or patch. In the case of trowel applied patching compounds, two coats are usually necessary in order to assure the complete coating of the floor. When in doubt contact the product manufacture for technical assistance.
*Because asbestos is a known carcinogen, local and federal authorities will have restrictions and specifications outlining its correct removal. The above information on Cutback removal should be handled by a professional. If you have questions please consult your Lumber Liquidator Tech and Installation Team.
# Most floor covering manufacturers, adhesive companies and the Resilient Floor Covering Institute (RFCI) have specific warnings against the use of solvents and chemical adhesive removers since any residue of the adhesive remover left on the floor or in the cracks of the concrete may also dissolve the new adhesive or discolor floor coverings. If chemical removers were used, it is advisable to mechanically clean the surface of the concrete and then apply a cement type self-leveling underlayment prior to installation.
Thank you for choosing our products, we wish you success on your project!
Bob
Technical and Installation
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