After removing the existing flooring, sometimes dealing with the existing adhesive residue can be quite a task and many questions need answered.
What type of adhesive is it?
Is my new adhesive compatible with the existing adhesive? Does it contain *asbestos?
How can I remove this?
First of all, solvents and adhesive removers are not recommended for removing existing adhesive and then having flooring installed back over top by all flooring, patch, and adhesive manufacturers. These solvents and removers can get trapped in the concrete and cause the new adhesive to fail.
Many installers simply see adhesive residue and immediately skim coat over the old adhesive residue. Care must be taken here as not all patching manufacturers recommend skim coating over all types of adhesive residue.
The first complaint I ever went out on was at a hospital where a custom installation of flooring was failing in all the patient rooms. The hospital handed me a piece of patch about 3/8′′ thick and 2′ x 2′. I had never seen patch fail in such a large piece without crumbling. I went into one of the rooms where the floor was failing and observed a large raised area under the hospital bed. I was allowed to cut open the floor and sure enough, the flooring was adhered to the patch, but the patch was letting go from the subfloor. I cut out a larger area and sure enough, the installer poured a layer of patch over a 3/16′′ thick layer of carpet residue. The patch had nothing to bond to; the patch basically laid on top of the carpet adhesive layer and broke as the bed moved. I opened up more of the flooring and basically just lifted large pieces of patch right off the adhesive residue.
Below, I have researched what two of the leading patch manufacturer’s statements about skim coating over existing adhesive residue and how to properly do it:
Ardex Feather Finish – ARDEX FEATHER FINISH also can be installed over non-water-soluble adhesive residue on concrete only. The adhesive must first be tested to make certain it is not water- soluble. Water-soluble adhesives must be removed mechanically down to clean concrete.
Non-water-soluble adhesives should be prepared to a thin, well-bonded residue using the wet- scraping technique as recommended by the Resilient Floor Covering Institute (www.rfci.com) to remove thick areas and adhesive build-up, as well as any areas that are weak or not well bonded to the concrete. Any existing patches below the adhesive must be removed completely.
Mapei Plani Patch or Planiprep SC – When going over adhesive residue with Planipatch you will need to use the latex additive Planipatch Plus. Below are the options
Best- 2 coat system
1st coat Planipatch with full strength Planipatch Plus
2nd coat Planipatch with diluted Planipatch Plus Better
Option 1- Planipatch with diluted Planipatch Plus Option 2- Planiprep SC
Another option is to use a coating to encapsulate the old existing adhesive residue. There are two products on the market that I know of (JJ Haines carries both) for going over existing adhesive residue:
DriTac ECO DriBloc, formerly known as DriSeal. DriTac Eco-DriBloc is a one-component, fast dry- ing concrete moisture control system and adhesive isolation membrane that allows installers to apply a moisture mitigation system and install their floor covering the same day. This roller applied “green” product also serves to isolate old adhesive residue, including cutback. It’s an easy-to-use 2-In-1 product that offers a zero VOC, zero solvent and low odor formula. Eco- DriBloc is now warranted to reduce up to 15-lbs. of concrete moisture vapor transmission down to 3 lbs. in 24 hours, per the ASTM F1869 Calcium Chloride Test Method and control up to 90% Relative Humidity (RH), per the ASTM 2170 Relative Humidity Test.
1-Coat = 12-lbs Calcium Chloride – 85% Relative Humidity – 3-hour dry time 2-Coats = 15-lbs Calcium Chloride – 90% Relative Humidity – 24-hour dry time
Eco- DriBloc is for use under most types of floor coverings, including Engineered Hardwood, Luxury Vinyl Tile & Plank, Fiberglass Back Sheet Vinyl, Carpet Tile, VCT, Cork Tile, Cork/Rubber Foam Underlayments, Laminate flooring and all other floating floors. This product contains zero VOCs, zero solvents and has very low odor. Eco- DriBloc is an extremely easy-to-use, roller applied product that offers easy clean up. It can be used over porous concrete to help reduce penetration of the adhesive and dusting of the concrete, which results in increased spread rates and stronger bond with floor covering adhesives. Eco- DriBloc is compatible with all DriTac water-based adhesives.
XL Brands TriSeal Adhesive Residue Encapsulator – Triseal is a light-colored, high-strength acrylic polymer compound formulated to isolate *cutback and other types of old adhesive residues that would affect the bond of the new floor adhesive over concrete substrates. Prior to the installation of floor covering systems, Triseal will also seal floors in dusty conditions, providing a clean surface for better adhesive bonds. Triseal is solvent free and contains “zero” (calculated) VOC. Use over old cutback, multi-purpose and pressure sensitive adhesive residues. Triseal is not recommended for use in conjunction with polyurethane-based adhesives.
Regardless of which product or system you choose to use, you will have to prepare the existing adhesive residue. The existing adhesives must be mechanically scraped down to a bare residue flat with the substrate. Do not use solvent or liquid cleaners to remove old adhesive.
Bottom line is you now have some options for going over old adhesive residue, but you will to take the proper steps to prepare the adhesive residue to get the results your customer desires.
*Please note, old asphaltic cutback adhesive did contain asbestos and special care must be taken.
Various federal, state and local government agencies have regulations governing the removal of in-place asbestos-containing material. If you contemplate the removal of a resilient floor covering structure that contains (or is presumed to contain) asbestos, you must review and comply with all applicable regulations.
Vinyl-asbestos tile and asphalt tile contain asbestos fibers, as did some asphaltic “cutback” adhesives and the backings of many sheet vinyl floorings and lining felts. The presence of the asbestos in these products is not readily identifiable.
Unless positively certain that the product is a non-asbestos containing material, you must presume it contains asbestos. Regulations may require that the material be tested to determine asbestos content.
Asbestos was removed from asphaltic cutback adhesive in 1983.
Existing in-place resilient floor covering and asphaltic adhesives — Do not sand, dry sweep, dry scrape, drill, saw, beadblast, or mechanically chip or pulverize existing resilient flooring, backing, lining felt, asphaltic “cut-back” adhesives, or other adhesives.
These existing in-place products may contain either asbestos fibers and/or crystalline silica. Avoid creating dust. Inhalation of such dust is a cancer and respiratory tract hazard. Smoking by individuals exposed to asbestos fibers greatly increases the risk of serious bodily harm.
Unless positively certain that the product is a non-asbestos containing material, you must presume it contains asbestos. Regulations may require that the material be tested to determine asbestos content and may govern the removal and disposal of material.
See current edition of the Resilient Floor Covering Institute (RFCI) publication “Recommended Work Practices for Removal of Resilient Floor Coverings” for instructions on removing all resilient floor covering structures.