Strategies for leaving asbestos-containing floor tiles or sheet flooring safely in place in a building:

Choosing an appropriate material to cover-up or coat the surface of a sound, well-adhered floor can protect against future damage or asbestos particle release in the building.

This article series assists building buyers, owners or occupants in reducing the risk of asbestos exposure from flooring that contains or is suspected to contain asbestos.

We provide photographs and descriptive text of asbestos insulation and other asbestos-containing products to permit identification of definite, probable, or possible asbestos materials in buildings.

Page top photo: vinyl asbestos floor tiles in the kitchen of a 1970's home - before covering over with epoxy floor paint.

Sealants For Asbestos-Containing Floor Tiles Left In Place

Advice About Covering or Sealing Asbestos Floor Tiles

Asbestos is safe and legal to remain in homes or public buildings as long as the asbestos materials are in good condition and the asbestos can not be released into the air. - US EPA

Photo at left: ceramic tile installed directly over asphalt-asbestos floor tile in a 1970's home formed a complete seal and a safe walking surface. But other, easier and less costly options are available and are described here.

Bottom line: The most economical renovation procedure for asbestos-floor tiles would be to leave the tiles in place, covering it with a layer of new flooring material. If there is minor damage - a few broken tiles, usually those can be simply picked up for disposal either as construction debris or as hazardous material (depending on regulations where you live).

If you want to leave asbestos-containing floor tiles in place without installing a new layer of flooring over-top of it then you should consider using one of the floor sealants described on this page.

Even where old floor tiles are removed, using the sealants described here mean that you won't have to also remove remnants of asbestos-containing floor tile mastic adhesives.

Photo at left: ceramic tile installed directly over asphalt-asbestos floor tile in a 1970's home formed a complete seal and a safe walking surface.

Asbestos is an airborne particle hazard. Asbestos-containing flooring in good condition and not being disturbed by demolition is not highly hazardous. That is, it's not likey to release harmul or even detectable levels of airborne asbestos.

Asphalt-asbestos or vinyl-asbestos flooring not like something that "emits" a hazard such as radioactive materials. So if the material is sound, intact, undisturbed, the risk of particle release is very low.

But if you are planning demolition it's prudent to treat old asphalt-asbestos or vinyl-asbestos floor tiles or sheet flooring as "PACM" or "Presumed Asbestos Containing Material". If you must demolish old flooring then it makes sense to test representative samples for asbestos as if it's tested as asbestos-free the demolition cost will be significantly less.

Watch out: even without asbestos, demolition dust is often harmful and should be controlled, and the jobsite properly cleaned when the demolition is complete.

Article Contents

• OPTIONS for LEAVING ASBESTOS-CONTAINING FLOORING IN PLACE
• EXAMPLES of ASBESTOS FLOORING COVERINGS THAT WORK
• ASBESTOS FLOOR TILE OR MASTIC SEALANT COATINGS / PAINTS

...

Options for Reducing the Hazard of Asbestos-Containing Flooring Left in Place

You can reduce the hazard from asbestos-containing floor tiles by several measures that we list here and by other suggestions in government documents and references we will cite.

• Leave the floor covering in place & seal it with a special "paint"
  
  In residential applications if the flooring is in good condition you can gently clean, restore, and coat the flooring with an epoxy paint or with a clear restorative coating.
  
  Below we illustrate this procedure using epoxy floor paint. But a range of coating products is avaliable, as wel'll provide below.
• You can simply cover the suspect flooring with a new material: -
  
  - wall to wall carpeting -- vinyl or sheet resilient flooring -- new layer of resilient tile flooring -- a wooden subfloor and new resilient tile flooring. At above left we illustrate this result: ceramic tiles have been installed atop the original floor covering.
• If your new floor is to be tile placed on top of old asbestos tile flooring,
  
  you might need to use a floor filler over openings left where broken tiles were removed, so that the floor surface below the new flooring is adequately smooth.
• If the floor structure is sufficiently rigid so as to avoid flexing and cracking, ceramic tile can also be installed 
  
  over an appropriate subfloor layer
• If the floor surface is in good condition (no loose, broken tiles)
  
  and is in a residential area (not a school or public space) and not subject to heavy wear or use of mechanical grinders, buffers, etc., you might consider cleaning the floor surface (washing), painting it with an epoxy floor paint,
  
  and if/when the epoxy painted surface is scuffed, restore that surface with a floor cleaning and rejuvenation product that adds additional clear coat layers.
• Use a HEPA vacuum cleaner 
  
  when cleaning up house dust as that type of filter will capture most ultra small particles including asbestos dust if such is even present
• Do not use floor sanders, power or machine driven floor polishers 
  
  on asbestos-suspect flooring
• Watch out: Do not permit demolition of the floor 
  
  without taking appropriate asbestos-dust control measures

...

Examples of asbestos floor tile or sheet flooring cover-ups that can work

• Carpeting 
  
  (we don't recommend wall to wall carpets in basements nor in bathrooms)
• A new layer of resilient flooring,
  
  sheet or tiles, installed directly over the existing floor covering (typically using mastic) provided the current floor surface is smooth and sound
• A new layer of resilient flooring, sheet or tiles, installed over hardboard 
  
  or other solid underlayment that is placed over the existing floor covering and secured by nails or screws to framing below in order to provide a smooth leveling surface.
• A new layer of resilient flooring, sheet or tiles, installed over a pour-on leveling compound (a concrete mix)
  
  used to level uneven floors (most suitable for concrete slab floors, may not be recommended over a wood framed-floor that is not framed solidly enough to resist flexing as the concrete pour-on underlayment may crack)
• A layer of epoxy floor paint 
  
  and one or more layers of clear coat sealant.
  
  This process is described at ASBESTOS FLOORING LEFT IN PLACE-EPOXY PAINT
  
  at ASBESTOS FLOORING LEFT IN PLACE
• Coating good condition asbestos floor tiles 
  
  with a rejuvenating sealant or gloss topcoat. This approach using an epoxy floor paint is discussed and illustrated just below.
  
  Also see ASBESTOS ENCAPSULANTS & SEALERS - coatings, encapsulants, fiber release control for asbestos containing materials

Watch out:  We do not recommend installing ceramic tile over a wood-framed floor before you have checked the flexibility of the floor system, in particular if the floor framing covers a larger span, say a dining room, or an area of heavy usage, say an entry hallway. The worry is that flexing floor framing may cause cracks in the ceramic tile job. Usually the floor can be stiffened sufficiently to avoid cracking either by reinforcing framing from below or by adding a layer of stiff underlayment.

Watch out:  when adding a new layer of floor covering that requires underlayment or leveling compound, the increase in floor height where it abuts adjacent flooring of other rooms can create a trip hazard.

...

Paints & Floor Sealants for Floor Tile Mastics / Cutback Adhesives

Where some or all old floor tiles have been removed the floor tile adhesive, also called cut-back adhesive or tile mastic will remain. Removing old floor tile cutback adhesive is a horrible job that you should avoid in favor of covering the floor with resilient tile or sheet flooring, carpeting, engineered wood, laminate flooring or a similar product.

However there are at least two situations in which we need to paint over and seal exposed floor tile adhesive even for a floor we intend to cover.

1. We intend to paint over spots where floor tiles were removed (with epoxy floor paint)
   
   and keep the original tiles in place without adding new layers of flooring,
   
   but there are a few areas where tiles lifted or were removed, exposing the floor tile mastic. Before gluing down replacement tiles in preparation for epoxy-painting we might want to prepare the old mastic-coated surface to be sure that the replacement floor tiles will remain glued in place.
   
   Using epoxy paint to seal and keep an old asbestos-containing tile floor is described beginning
   
   at ASBESTOS FLOORING LEFT IN PLACE
2. We need to level spots where floor tiles were removed
   
   so that variations in the original floor surface don't telegraph up through a new layer of resilient sheet flooring to be installed.
   
   Here too we want to prepare the old mastic-coated surface to be sure that the floor leveling compound we apply, or fill-in floor tiles that we stick down will remain in place beneath the new resilient floor.
   
   Using leveling compounds or glue-down filler tiles to level out an old tiled floor prior to covering it with resilient sheet flooring or epoxy paint is described
   
   at FLOOR TILE BASE LEVELING

There are at least three floor tile mastics / cutback adhesives you may encounter:

Black Asphalt-Based Floor Tile Mastic

Black asphalt-based floor tile adhesive

often contained asbestos. This material is not friable unless some fool runs a power sander or scraper over it.

Although it can be partly removed using organic solvents, that approach is dangerous and unnecessary unless you are trying to restore a historic and valuable wood floor below.

Instead it's better to leave this adhesive in place and to cover-over the floor with new flooring materials.

If the floor is to be covered with a new layer of flooring

such as sheet vinyl or vinyl tiles or even carpet padding and carpeting, there is essentially no risk that asbestos particles can move up from the old floor into the occupied space; nothing is abrading the old asbestos-containing floor tiles and they're covered by a membrane of one or more layers of new material

If however you do not want to add more layers of flooring material

another option is to clean and seal the original asbestos-containing floor tiles using an epoxy paint designed for use on floors. I've found that that treatment is very durable - having tested our original installation in a building for nearly twenty years.

Tan or Brown Solvent-Based Floor Cut-Back Adhesive

Solvent-based tan floor tile mastic: Some tan or brown colored floor tile or resilient flooring adhesives were organic-solvent based and can be dissolved and scraped up but the process is difficult, involves working with potentially dangerous solvents, and is probably a bad idea.

Tan or Brown Water-Based Flooring Adhesive

Water-based tan or brown floor tile adhesive: Some tan or brown-colored floor tile or sheet flooring adhesives were water based and can be dissolved and scraped up using simple water.

I [DF] removed water soluble tan floor tile mastic in a small area at an entry door in Wappingers Falls, NY after first trying odorless paint thinner, lacquer thinner and other terrible stuff. To my shock water took the adhesive right up. But this was an exception to the general experience.

For another approach to sealing a damaged asphalt- or vinyl-asbestos tiled floor that's uneven and damaged,

see POURED-IN-PLACE FLOORING, RESILIENT - pour on a whole new floor surface

Mastic-Coated Floor Paint & Sealant Products

Illustration: PerfectPrimer® being painted over an old floor surface with cut-back adhesive, adapted from the company's literature, cited below.

Watch out: some primer/sealer paints and possibly some floor leveling compounds will react with or partially-dissolve or bleed-through or bond poorly with tile mastic adhesives, particularly asphalt-based adhesive.

Be sure that the products you use are described by their manufacturer as suitable for painting over floor cutback adhesive. Here are some examples.

• ASBESTOS ENCAPSULANTS & SEALERS - for our complete list of encapsulants and sealants suitable for use on asbestos-containing surfaces & other building surfaces where asbestos products were removed or where flooring is to remain in place
• Fiberlock SerpiFlex Asbestos Encapsulant [PDF]
  
  Website except: SerpiFlex Asbestos Encapsulant is a concentrated water-based vinyl acrylic product with various flameretardant chemicals and fillers. It is nontoxic, non-combustible and does not contain any solvents or silicates. Available in clear, white and colors.
• Mapei PRIMER T [PDF] MAPEI Americas Headquarters 1144 E. Newport Center Drive Deerfield Beach, Florida 33442 USA, Technical Service: 1-800-992-6273 (U.S. and Puerto Rico) or 1-800-361-9309 (Canada). For help with locating a distributor of MAPEI products, call Customer Service at 1-800-426-2734 (1-800-42-MAPEI).
  
  Website Excerpts: Use Primer T when applying a self-leveling underlayment on properly prepared suitable substrates.
  
  Primer T is a low-VOC, magenta-colored, water-based acrylic primer that enhances the performance and adhesion of self-leveling underlayments (SLUs) on nonporous and porous substrates. Suitable for a wide variety of substrates, Primer T combines excellent versatility with easy, low-odor application.
• PerfectPrimer, Specialty Solutions Manufacturing, Inc., 119 South 3d St New Hyde Park, NY 11040 USA Tel: 718 736 8477 Web: PerfectPrimer.com Email: info@perfectprimer.com
  
  This sealant is marketed as safe for use over asbestos tiles, concrete, and mastics and is described by the company as an asbestos encapsulant.
  
  Website excerpt: PerfectPrimer® is a complete floor prep system and universal primer/sealer. It forms a powerful molecular bond between nearly every coating or modified cement, with any clean, sound substrate including: wood, cut-back glue, sealed concrete, metal, roofing materials, ceramic tile, VCT, epoxies, masonry, and linoleum.
  
  The company provides these and other helpful guides:
  
  PerfectPrimer® for ASBESTOS ENCAPSULATION & OVER MASTICS [PDF] retrieved 2019/11/10 original source: op. cit.
  
  PerfectPrimer® APPLICATION GUIDE [PDF] retrieved 2019/11/10 original source: op. cit.
  
  Watch out: according to the company's primer selection chart, PerfectPrimer will bond to most coatings and virtually any surface, but it is not designed for use on uncoated concrete nor below-grade nor on rusty surfaces. Contact the company directly for product selection advice.
  
  
• POURED-IN-PLACE FLOORING, RESILIENT - pour on a whole new floor surface

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Reader Question: What are the options for covering asbestos-suspect floor tiles or sheet flooring?

We are renovating a small bathroom that has resilient flooring of uncertain age, but from the style we think the floor tiles are from the 70s.

We want to cover this floor tile to avoid an asbestos hazard. What are some options. - Anon.

Reply: asbestos-containing flooring in good condition is not "radioactive" and does not spontaneously emit harmful particles

Remember that the hazard from asbestos-containing floor tiles is not like something that's "radioactive" - if the flooring is not damaged, if you avoid making a dusty mess by demolition, and more, if it the flooring can be covered and protected from damage, it is not harmful if left in place.

Current best asbestos advice is to avoid the dust and mess of demolition of vinyl asbestos flooring if you can simply cover it with another material.

Question: how can we identify these 1950's 9x9" basement floor tiles to find out if they're "asbestos" ?

We are planning to gut and remodel a basement in a house we have been living in for a few years now. The basement previously was used just for storage, but we want usable space there.

About 400 Sq ft of the 700 we will be remodeling has existing tile while the rest is just painted cement floor.

Some of the tile is missing, one section cracked, but covered with foam play mats, which my wife installed initially when the house was purchased.

These are 9x9 tiles, and we have no idea about history or age.

The house is a 1950s home, but it is not clear when the basement tile was installed. A search online lead me to your site, and they do look like Armstrong tiles possibly, but I wanted to get an opinion from somebody with more expertise.

Me plan was to have the floor removed and to go with an epoxy floor covering, as it is a basement floor, where water is always a possibility and carpet is not something we want to risk.

If it is not advised, and it would be better suited to go with a different floor covering, we would still need to deal with the areas missing tile, but we have a contractor that can aide in this.

I will attach some photos that hopefully can help identify the tiles in question. - Anonymous by private email 2018/06/02

Reply: asbestos-containing flooring does not mean we have to undertake an expensive and dangerous asbestos removal project

You will find an exact match to your flooring in the ID-library of asbestos flooring beginning

at ASBESTOS FLOOR TILE IDENTIFICATION PHOTOS 1949-1959- (floor tiles) where you'll see your flooring in the early Armstrong (or similar manufacturers) vinyl asbestos or asphalt asbestos 9x9" (and other sizes) flooring.

Do you need to test the floor for asbestos?

From the age and appearance of the floor, I would not bother testing it for asbestos, spending instead on proper cleanup and sealing of the surface.

Even without testing, given the appearance and known age of your floor, it would be prudent to treat such flooring as "PACM" or "Presumed Asbestos Containing Material".

The presence of known asbestos-containing flooring does not mean we should panic nor that we should undertake an expensive and dangerous asbestos removal project.

Do you have to remove the existing floor tiles?

Asbestos is safe and legal to remain in homes or public buildings as long as the asbestos materials are in good condition and the asbestos can not be released into the air.

Generally the safest approach is to leave such flooring alone and to cover it with a coating or with another layer of flooring.

Keep in mind that even if you removed the floor tiles the remains of the mastic adhesive below would make use of an epoxy floor paint problematic - it may not properly adhere. You'd need to also remove the adhesive (which may also contain asbestos), and then clean the surface to make it bond with the floor paint.

All of that demolition and cleaning, performed properly and safely, would be quite costly. If the rest of your floor is sound and well-adhered, that expense is probably not necessary.

Options for leaving the flooring in place

For the situation you describe,

see ASBESTOS FLOORING LEFT IN PLACE where we describe using an epoxy coating on a floor in generally good condition and provided that the remaining floor tiles are well-adhered to the floor below.

You can buy floor tiles that can fill-in the voids in the existing floor. Select a floor tile of the same thickness and surface texture (not embossed). Armstrong as well as other floor tile manufacturers sell floor tiles in various thicknesses, one of which should match the thickness of the existing tiles.

Other advice on various options for an asbestos-floor tile is

at ASBESTOS FLOORING HAZARD REDUCTION

For a floor whose tiles are well adhered except for small areas of damage such as you show, I would prefer to damp-wipe clean up a few broken tiles, replace missing ones with new tiles of the same thickness, then epoxy-seal or otherwise cover-over (sheet vinyl) the existing floor.

If you must remove the 9x9 asbestos-suspect flooring

Watch out: If when you remove the rest of the current covering over the floor you find a significant number of loose, poorly-adhered, or broken floor tiles, OR if for other reasons you are compelled to remove the floor (not the recommended option)

see ASBESTOS FLOORING REMOVAL GUIDE .

Watch out: Do not run a conventional vacuum cleaner over such areas as you'll just cause more particles to become airborne.

On any of our asbestos-related InspectApedia pages, at CONTINUE READING you will find

a complete ARTICLE INDEX to ASBESTOS HAZARDS

For advice on handling irregularities in floor surface after loose floor tiles have been removed see

RESILIENT FLOORING VINYL or CORK

We would have much appreciated hearing any comments, criticize, suggestions, or further questions that you may have taken after you've taken a look at the articles I've cited.

On 2023-10-08 by RE-posted from private email (mod) - what is the best underlayment to use before installing vinyl flooring over asbestos tiles ?

I really enjoy your site. I was wondering what is the best underlayment to use before installing vinyl flooring over asbestos tiles ? Also is it okay to remove the tack strip from the tiles from an old carpet that was over the tile ?

Do you know anyone who can repair wood floors in NJ ?

I have a couple loose boards.

T.P. by private email 2023/06/05

On 2023-10-08 by InspectApedia Publisher - wood floor repair help needed

@T.P.,

I do no have a specific wood floor repair specialist in New Jersey - it's a pretty big state. I'd suggest a local search for both wood floor installers and carpenters.

But to have an idea if they're qualified, you might first want to read up on the topic; some repairs of loose floors are very easy - if there's access from below.

See:

LOOSE NOISY FLOOR REPAIR

and see our library on this topic at

WOOD FLOOR DAMAGE REPAIR

On 2023-10-08 by T.P.

@InspectApedia Publisher,

Hey Dan,

Hope all is well. Is a floating vinyl floor a safe way to encapsulate black mastic on a concrete slab ? The tiles were removed and the mastic was painted over.

After doing work in that room seems that some of the mastic has bled through in spots.

On 2023-10-08 by InspectApedia Publisher - Is a floating vinyl floor a safe way to encapsulate black mastic on a concrete slab ?

@T.P.,

I think that's fine although I would prefer of course to see an underlayment or an application of a sealant to the tile mastic before installing the floating floor.

If your floor paint coating has bled through where painted over old tile mastic adhesive I'm guessing that the mastic was asphaltic (black) and that the paint used wasn't the best product.

The asbestos floor and floor mastic adhesives listed above on this page are specifically formulated to paint over adhesives without bleed-through.

However, as long as the coating is sound then the bleed-through is a cosmetic detail that will be covered when you install new flooring. - 7 October 2023

On 2023-10-08 by T.P.

@InspectApedia Publisher,

Thank you for getting back to me.

I am also planning on doing a coat of Ames liquid rubber waterproof sealant on the slab over it.

Do you think that would be better ?

On 2023-10-08 by InspectApedia Publisher - using a paint specifically formulated to adhere to tile mastic is likely to give the best performance

@T.P.,

Not really; using a paint specifically formulated to adhere to tile mastic is likely to give the best performance.

About waterproofing the slab surface, I appreciate the appeal of that but in my experience key is finding and fixing sources of water entry such as gutters spilling by the foundation or in-slope grade.

Watch out: If your basement has had water entry then we should address that before spending on that new floor.

I've tested various waterproofing coatings on concrete floors in basements that had a water entry problem.

When water is coming up under or through the floor slab or at cracks in the slab, the thin waterproofing coating on that interior surface is being called to do more than can reasonably be expected, and in every case I've seen over five decades, the coating eventually bubbled, peeled, or failed on floors where it was left as a lone floor coating and where the water entry source had not been corrected.

Such coatings are like the little Dutch boy with his finger in the dike.

The product is primarily intended for use on walls; where used on exterior walls the company says that it needs to be top-coated with an acrylic top coat as the coating is UV sensitive. So we think they're describing use outdoors, above-grade, exposed to sunlight. (Not your situation).

Here is how Ames describes their product:

"Ames Block & Wall™ Liquid Rubber Waterproofer Multi-Purpose Coating & Sealant - 1 Gallon - Perfect to Use As Concrete Sealer and Waterproofer for Basements and Foundations "

Ames does make sealants that the company says can be used as under tile waterproofing (Ames Blue Max Waterproofing) but the focus of these products is waterproofing, not asbestos mastic sealing, and I'm not sure how well the sealant will adhere to an asphalt-based mastic coated surface - that's a question you could ask the company.

Contact
AMES RESEARCH LABORATORIES, INC.
1891 16TH ST SE
SALEM, OR 97302 888-345-0809
Tel: 888-345-0809
Phone: 888-345-0809 (U.S. & Canada only) or 503-588-3330
Email: sales@amesresearch.com
Main Office
Phone: 503-588-7000
Fax: 503-364-2380
Email: customerservice@amesresearch.com

Or try
Conspec Materials
5403 West Crenshaw Street
Tampa, FL 33634 USA
Tel: 813-885-4324

At that company's website conspecmaterials.com we found links to product description PDFs but both of them were dead links, so we're still looking for detailed product application instructions.

On 2023-06-28 by D - can I put Fiberlock over black mastic before new flooring is laid down?

We had to replace some floorboads in our bathroom and decided to replace the flooring as well. After ripping out the flooring I have some subflooring with what looks like black mastic material on it.

Is it alright to go right over it with Fiberlock and then put the new flooring in?

On 2023-06-28 by InspectApedia Publisher

@D,

If you damp wipe and HEPAVAC and then let the floor dry out you've produced as clean and sound of surface as you can.

If you then use one of the sealants discussed above you'll probably find your new floor installation will bond better and more reliably to the subfloor so that's what I recommend.

On 2023-05-26 by Polu - opinion on using a polyutherane clear coat sealant on concrete subfloor with black mastic that is 2% non friable asbestos?

What is your opinion on using a polyutherane clear coat sealant on concrete subfloor with black mastic that is 2% non friable asbestos?

Afterwards it will be covered by a moisture barrier and floating floor.

Reply by (mod) - polyurethane clear coat sealant on concrete subfloor with black mastic

Solvent-based polyurethanes contain di- and tri-isocyanates and polyols and other ingredients.

While you'd want to consult a paint chemist for a technically confident answer, I'm concerned that some solvent-based polyurethanes might have a softening, dissolving effect on the existing floor tile mastic-adhesive - resin based products.

That may be why companies selling products specifically formulated for sealing black mastic adhesive coated floors as a step in installing new flooring, use other products.

We discuss and recommend using a sealant coating that is intended for use over mastic adhesives,

above on this page - FLOORING ADHESIVE MASTIC SEALANTS

and also in more detail with more product options at

https://inspectapedia.com/hazmat/Asbestos-Sealers-Encapsulants.php ASBESTOS ENCAPSULANTS & SEALERS

Watch out: keep in mind that a water based polyurethane is of course chemically different but then, some floor tile mastic adhesives are also water soluble.

I'd stick with products specifically intended for use over black mastic floor tile adhesive. Typically you can install new flooring directly atop that sealant.

On 2023-04-16 by Kimberly - what kind of glue I can use to adhere the old wood tiles directly back again to the old cement?

Hi, I have a 1958 Eichler built home in CA, cement slab foundation with radiant heat pipes embedded. Recently pipe leaked, 6" parquet wood tiles buckled up, cement was jackhammered, pipe fixed.

I am left with a 6' x 4' area of slight black mastic on cement and somewhat more on the back of wood tiles that I want to reuse. I was warned that a new glue could dissolve the old asphalt based mastic and make a tarry mess that won't adhere and set properly.

I've asked around and no answers yet - I need to know - what kind of glue I can use to adhere the old wood tiles directly back again to the old cement, both of which have old blk mastic on them?

Hope to get an answer ASAP! I don't want to use the "Perfect Primer" as that will add more time, cost and height to the repair so it won't be flush - this repair is in center of room. Thank you.

On 2023-04-16 by InspectApedia Editor

@Kimberly,

Sure, we're glad to help.

Just take a look at and choose from the examples of

FLOORING ADHESIVE MASTIC SEALANTS - if you need to glue down new floor or add a leveling compound over old tile mastic

There may be other products but reading that page will show you what you're looking for.

The good news is that this isn't a problem that no one has ever faced.

These sealers are formulated to paint over old asphalt-based adhesive mastic without dissolving it - a feature for which you'll check before buying the particular one you choose.

You will need to clean the old surface and be sure nothing is sticking up so high that your new parquet tiles won't be level with the floor above - so prep the area and test-fit the tiles before applying the sealer, test again after it's in place, then use a thin-set flooring mastic adhesive.

On 2022-11-07 by Tammy - What can I use to put over old 50s floor tile to seal it

What can I use to put over old 50s floor tile to seal it so I can put other flooring down

On 2022-11-07 by InspectApedia (Editor)

@Tammy,

There are sealants sold specifically for that purpose as you will find described and listed above on this page

And at
ASBESTOS ENCAPSULANTS & SEALERS

Please take a look and let me know if any of that leaves you with questions.

On 2022-10-06 by Jojo - Norsk interlocking garage-style PVC floor tiles over old mastic adhesive left afterr taking out asbestos-containing tiles

I had the asbestos-containing tiles professionally removed from my basement’s concrete slab, and the underlying black mastic was scraped down but partially remains in areas after that removal process.

I put down Norsk interlocking garage-style PVC floor tiles directly over the mastic, thinking that would provide a suitable barrier, but now I have concerns.

If I lift up a tile, I can see in some areas that a tiny amount of mastic has transferred to the underside of the tile. See the small black spot in the attached image.

This makes me worry that walking on the PVC tiles will continue to disturb the mastic.

Should I pull up the PVC tiles and paint the mastic with a sealant? Or would a layer of 6-mil plastic be sufficient? If so, does the plastic need to be taped to the slab at the perimeter? Thanks.

On 2022-10-07 by InspectApedia-911 (mod) - Norsk interlocking garage-style PVC floor tiles

@Jojo,

That black tile mastic adhesive is not a friable material. It's not at all likely that there is a detectable or measurable asbestos hazard from the condition that you describe.

However if it's going to make you anxious, that worry itself is bad for your health.

A solution would be to paint the mastic surface with one of the mastic sealant encapsulant paints that we describe in this article series.

 

On 2022-08-10 by Tom - do I need to prime the cured Fiberlock and remaining tiles before applying epoxy?

We have/had vinyl tiles on our concrete basement floor since we moved in 36 years ago. Half the floor is in my workshop where all the tiles are intact and well adhered. The other half of basement is mostly exposed black mastic and a few tiles (well adhered). This is how the basement floor was when we moved in.

We've never done anything about them before but recently had them tested. The black mastic is positive for asbestos. I plan to encapsulate everything.

If I use a product like Fiberlock ABC on the exposed mastic and then cover everything with an epoxy paint do I need to prime the cured Fiberlock and remaining tiles before applying epoxy?

If so what kind of primer can I use to insure adhesion between the epoxy and Fiberlock and between the vinyl squares and epoxy?

Finally, can I apply all 3 of these items with standard 3/8" nap paint roller and brush? Thank you.

On 2022-08-10 by InspectApedia-911 (mod)

@Tom,

Thank you for a helpful question.

RE: "do I need to prime the cured Fiberlock and remaining tiles before applying epoxy?"

No. Sealants sold for use on mastic-coated floors or atop asphalt-asbestos or vinyl-asbestos floor tiles generally say right in their instructions that they're formulated with sufficient strength that you can tile over the sealant without an intermediate coat (such as the epoxy you suggest).

Where we used epoxy paint was on asbestos tile flooring that was to be left in place and painted over, so that the epoxy paint actually formed the walking surface.

Those details are at ASBESTOS FLOORING LEFT IN PLACE - using an expoxy floor paint over asbestos-containing floor tiles or sheet flooring.

On 2022-05-20 by Cindy - Covering asbestos flooring or mastic with carpeting is OK?

Can this floor be covered with carpet ? It tested positive for asbestos

On 2022-05-21 by InspectApedia-911 (mod) - Covering asbestos flooring or mastic

@Cindy,

Yes it can.

Covering asbestos flooring or mastic is the recommended EPA approach and is safest and most economical.

But because the mastic maybe a little bit sticky and for your own peace of mind, you might want to paint it first with a sealant such as those discussed in this article series.

Details are at ASBESTOS FLOORING LEFT IN PLACE

On 2022-02-18 by John - 1950s home with 9x9 VAT tiles in the basement - what do I do to cover or seal them

I have a 1950s home with 9x9 VAT tiles in the basement. They are installed on a floating concrete slab. I had originally planned to encapsulate it but some of the tiles are in bad shape. There are several that are cracked/broken or missing entirely. There are pieces of tile in the drain weep channel around the concrete slab too.

Someone also removed some tiles in one small area that had white mastic at some point in the past. The rest based on what's come loose or is missing have black mastic. The majority of tiles are still adhered to the floor.

Several have shown efflorescence due to hydro static pressure or moisture in the concrete slab which has caused them to unglue from the floor.

I'm unsure which avenue to go now considering the moisture problem with the slab ie: professional abatement, try to repair loose tiles and encapsulate. Any suggestions? Thanks.

On 2022-02-18 by Inspectapedia Com Moderator

@John,

Loose tiles that can easily be picked up without having to grind, chop, saw, etc. are pretty safe as the material itself is not friable. Pick up and toss out as construction debris.

Then you can use a sealant as discussed above on this page, and install new flooring atop the old.

If the missing tiles are few, you could fill the space with any modern tile of same thickness, then an alternative is to clean the floor (to remove wax dirt etc) and seal with an epoxy floor paint.

Details are at

ASBESTOS FLOORING LEFT IN PLACE - using an epoxy floor paint over asbestos-containing floor tiles or sheet flooring.

live link given above and at "Recommended Articles." at the end of this page

 

On 2021-02-11 by Alex - use leveling compounds or filler tiles before flooring over asbestos tile floors

Have 1000 sqft of VAT. Ripped up carpet tack strips and want to put concrete patch over the broken tiles; prior to floating a wood/pergo/laminate floor.

Any suggestions on a good patch material?

Should I perfect prime over the VAT prior to floating the floor, or will a moister barrier and underlay on the floating floor suffice?

Or I can pay $2200 to have Tiles Removed by abatement, and then Perfect Prime over the Black Mastic, prior to floating floor.

What ya'll think?

On 2021-02-13 by danjoefriedman (mod)

FLOOR TILE BASE LEVELING describes using leveling compounds or filler tiles before flooring over asbestos tile floors

Please take a look, Alex, and of course ask or comment further if that leaves any questions or if you have suggestions for that article.

On 2021-02-05 by Bob - experience with PerfectPrimer products

Anyone have any experience with PerfectPrimer products and if they work and are non destructive to asbestos tile

On 2021-02-06 by danjoefriedman (mod) - ok product, aggressive marketing!

Bob:

This article discusses the floor primer about which you ask - above on this page; it's described as suitable for use on asphalt-asbestos floor tile, vinyl-asbestos floor tile, and also leftover floor tile mastic on surfaces.

Regrettably, once we named the product our web pages got so many self-promoting posts by someone promoting the company that we had to delete and block on-page ads from what no doubt is a perfectly good, successfully used primer-sealer.

On 2020-10-13 by Rob Byrnes - underlayment and vapor barrier below the floor - SIK MB would not adhere to the floor

Have VAT tile. We just removed old carpet and and padding. VAT in good shape. Removed cracked and all loose tiles all around the edge of the room from tack strips.

Applied a spot test of Sika MB but it did not adhere to the tile. I was planning to use this as a encapsulation before installing engineered hardwood.

Have tried a couple cleaners to clean the tile but still seems tacky. The VAT is on concrete slab. Could I use a 6 mil plastic as a vapor barrier? Do I need a vapor barrier?

On 2020-10-13 - by (mod)

Rob

It's common for engineered hardwood flooring instructions to call for an underlayment and vapor barrier below the floor - check with the manufacturer of your specific product but yes, 6 mil poly may be acceptable.

Here is an example of installation instructions

REWARD ENGINEERED HARDWOOD FLOORING INSTALLATION INSTRUCTIONS [PDF] original source: https://onflooring.com/sites/default/files/instructions/Reward_Eng_Hardwood_Install_Instructions.pdf

On 2020-07-18 by Paul - black mastic adhesive isn't really friable - is it safe to walk-on? Should we test our air for asbestos?

I own a house made in the 60's. In a recent conversation with a contractor in my home, it was noted that I had some 9x9 tiles loose in my basement in an area i was planning to remodel. She said they likely contained asbestos.

I examined the rest of my basement and found what the imprints or markings of 9x9 tiles which were removed before I purchased the home. I have no idea if they were removed properly assuming they had asbestos.

A newer tile 12x12 has been laid over; however, there are still parts the the 1500sq. ft. basement which are not covered by any tile. It appears that we have been walking on black mastic for five years since we purchased the home.

I have read that black mastic is not friable and the black stuff on our floors seems to be tough and not easily scraped

Is my family in danger while walking on it?

Should we test our air?

The inspector did not make any notes regarding this when we were considering the purchase, though it would have been easy to see, especially in one room that only has the black mastic on top of the concrete.

On 2020-07-20 - by (mod) -

Paul

You are correct that black mastic adhesive is not normally friable so even if it contains asbestos it would be unusual to detect a measurable Airborne level of asbestos from that source. Please keep in mind that no one with any sense is going to bet your money and health on an asbestos question with no more information than a brief tech. There could certainly be other conditions there that are unsafe.

It's too easy to tell you to do an air test and pass responsibility on to someone else and perhaps without pointing out that because the level of airborne particles in a building varies enormously, up to four orders of magnitude, depending on test conditions, such a test is in my opinion not so reliable is a general building screen forairborne hazards.

Visual inspection some of which you've already described as in my opinion more important

On 2020-06-20 by Luis - how do I prep our floor to install a layer of tile or wood: all the old tiles are covered with carpet glue?

I am renovating a room after pulling up the carpet I found 9x9 tiles all in good condition.

All the tiles are covered with carpet glue. The floor is not level and I was either going to install tile or wood. How can I prep the floor without scraping the glue off the tiles? The room is level with the garage, not a basement.

On 2020-06-20 - by (mod) -

What do you think about using one of the sealants discussed above, Luis? That should work fine.

...

Continue reading  at ASBESTOS FLOORING LEFT IN PLACE or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• ASBESTOS-CONTAINING ADHESIVES
• ASBESTOS ENCAPSULANTS & SEALERS - used on asbestos-containing materials
• ASBESTOS FLOORING HAZARD REDUCTION - home
• ASBESTOS FLOORING IDENTIFICATION
• ASBESTOS FLOORING HAZARD LEVEL ASSESSMENT
• ASBESTOS DISPOSAL REGULATIONS
• ASBESTOS FLOORING LEFT IN PLACE - using an epoxy floor paint over asbestos-containing floor tiles or sheet flooring.
• ASBESTOS FLOORING REMOVAL GUIDE
• ASBESTOS LEFT in PLACE in BUILDINGS - MANAGEMENT GUIDES - codes, regulations, procedures
• ASBESTOS REMOVAL, WETTING GUIDELINES
• DOES THIS FLOOR CONTAIN ASBESTOS? - 5 easy questions to tell if your FLOOR probably contains asbestos -
• FLOOR TILE BASE LEVELING describes using leveling compounds or filler-tiles before flooring-over asbestos tile floors
• FLOORING ADHESIVE MASTIC SEALANTS - used before gluing down new floor or add a leveling compound over old tile mastic
• FUNGICIDAL SEALANT USE GUIDE - used in mold remediation, for dust or mold or other particle control and in other indoor cleanup situations
• POURED-IN-PLACE FLOORING, RESILIENT
• RESILIENT FLOORING VINYL or CORK installation

Suggested citation for this web page

FLOORING ADHESIVE MASTIC SEALANTS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to ASBESTOS HAZARDS

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