After removing the existing flooring, sometimes dealing with the existing adhesive residue that has been left behind 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 break down just like it did to the old existing adhesive that was removed.
Note: Many adhesive removal products contain solvents that leave a residue within the subfloor. This residue can negatively affect the new adhesive and bleed through the new floor covering. The warranties provided by manufacturers of new floor covering materials will not cover instances where existing subfloor conditions damage their products or affect their installation.
Why Must it Be Removed?
The biggest issues with old adhesives can be staining and is my new flooring adhesive compatible with the existing adhesive residue on the subfloor.
Staining can come from the ingredients in the old adhesive. For instance, an old “black *cutback” adhesive and also some of the ingredients in a multipurpose adhesive will stain the backing and bleed up through the vinyl and fiberglass flooring products we have today.
If the old and new adhesives are not compatible, this can become a sticky and slimy mess. The old and new adhesive will fight one another and basically start to break down one another.
Many installers simply see adhesive residue and immediately skim coat over the old adhesive residue. Care must be taken here as most patching manufacturers do not recommend skim coating over all types of adhesive residue. Patching manufacturers only recommend going over non water soluble adhesives. Multipurpose and most carpet adhesives are water soluble. Think about it, I have an existing water soluble adhesive that will break down with water and now I pour a wet slurry of patching compound over this water soluble adhesive. This old adhesive residue could soften and let go under the patching compound. Also, patching over an old adhesive with the possibility of staining will do nothing. The stain will migrate up through the patching compound and stain the new flooring. Patch is porous and stains will migrate right up through them.
There are two products that Haines carries, DriTac Eco DriBloc (Haines item # DRIDBC4) and Parabond MVR 8000 (Haines item #PCAMVR8000). Both of these products are able to encapsulate both *cutback and water soluble adhesives.
DriTac Eco-DriBloc can be applied over carpet adhesive residue and asphalt cutback adhesive residue as long as the adhesive ridges and raised residue have been completely removed from the subfloor with only minor stains remaining. All soft, loose and raised residue must be removed before encapsulation begins. All adhesive residue must be hard, firm and well bonded. http://www.dritac.com/ productsEcoDriBloc.php
Parabond MVR 8000 can be used over wood or concrete substrates with old adhesive residue prior to the installation of new flooring. MVR 8000 can be used to encapsulate old adhesive residue, seal dusty substrates, reduce porosity of gypsum and is alkali resistant. http://www.royaladhesives.com/Files/ Parabond/MVR_8000_12052013-1–2-.pdf
Dealing with *Cutback Adhesive
Asphaltic *cutback adhesive is black in color and is usually found beneath vinyl tiles and flooring. Asbestos was mixed with this product to make it more durable. Depending on what type of flooring product is being installed on top of the *cutback adhesive, you do have some options.
With vinyl flooring, I can use the products listed above, DriTac DriBloc and Parabond MVR 8000 or I can patch over the *cutback adhesive residue. The question becomes is can I skim coat or do I need a layer of patch over the *cutback adhesive residue. This will depend on the patching material being used for the thickness application. I strongly suggest contacting the patch manufacturer for specific recom- mendations before proceeding.
Hardwood flooring, again, I can patch over the *cutback adhesive residue or the only adhesives I know of with a recommendation for going over *cutback adhesive residue are DriTac 7700 (Haines item #DRI77004P) and DriTac 7800 Adhesive (Haines item #DRI78004). http://www.dritac.com/products7700.php
Armstrong Vinyl Composition Tile Adhesives S-515, S-525, S-700, and S-750 may go over existing *cutback adhesive residue. Existing Adhesives must be left so that no ridges or puddles are evident and what remains is a thin, smooth film. http://www.floorexpert.com/articles/Subfloors_Underlayments/Residual-Adhesives-on-Concrete-Slabs -to-Receive-Resilient-Flooring?retURL=%2Fapex%2FknowledgeSearch%3Fk%3Ddegree%2Bof% 2Bremoval&popup=false&lang=en_US&KBArticleTypeLabel=Subfloors+% 26+Underlayments&KBArticleTitle=Residual+Adhesives+on+Concrete+Slabs+to+Receive+Resilient +Flooring&KBArticleName=Residual-Adhesives-on-Concrete-Slabs-to-Receive-Resilient- Flooring&KBArticleType=Subfloors_Underlayments__kav&KBArticleID=kAB61000000CaSm
Please note that I keep referring to the word adhesive “residue.” We are not going to be bonding, encapsulating, or patching over thick layers of existing adhesives. Remember, you are only as good as what you go over.
*Please note, old asphaltic cutback adhesive did contain asbestos and special care must be taken. Asbestos was removed from asphaltic cutback adhesive in 1983.
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.
DO NOT SAND, DRY SWEEP, DRY SCRAPE, DRILL, SAW, BEADBLAST, OR MECHANICALLY CHIP OR PULVERIZE EXISTING RESILIENT FLOORING, BACKING, LINING FELT, ASPHALTIC “CUTBACK” ADHESIVE, OR OTHER BLACK ADHESIVE. THESE PRODUCTS MAY CONTAIN ASBESTOS FIBERS AND/OR CRYSTALLINE
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.
Tim McAdoo has a vast array of knowledge and highly developed installation skills and qualifications that have been amassed over his 35 years in the floor covering industry which has covered manufacturing, product development, installation and installation training. Tim is a certified instructor for Armstrong and Bruce flooring products. While a member of the Armstrong Installation Training Team since 1984, Tim is privy to all the latest innovations and techniques used in the installation of their products. We are sure you will find your skills will be honed and improved after attending one of his programs.