Common in homes built in the 20th century, black mastic was used as an adhesive for ceramic tile, linoleum, and other flooring materials. When you remove that floor covering to make way for new flooring, you may encounter the mastic and wonder whether it is safe to remove. So before you do anything with black mastic in your home, it is important to identify it and deal with it appropriately.
Mastic is the general term for a type of glue-like flooring adhesive. Many modern mastics are latex, or water-based, and can be softened with water. Asphaltic cutback adhesive is an older type of mastic made with asphalt-based cement.
As a petroleum-based material, the cutback is not softened by water. Some cutback adhesives contained asbestos. It is commonly thought that asbestos was added to these compounds for fire-resistance. While this would have a residual effect, the primary purpose of the asbestos was to make the product more durable.
Asbestos is a highly fibrous material, and these fibers interlock to help strengthen mastic, insulationand many other household building products. You will only see black asbestos mastic after a floor covering has been removed. As the name suggests, black is its predominant color. But there may be traces of other colors, such as those from subflooring showing through the mastic or pieces of floor covering that were not completely removed. Note that some older latex water-based adhesives also were black, so color alone is not a reliable identification characteristic.
In most cases, black mastic lies flat against the subfloor, with no ridges, bumps, or gaps of any significance.
It often has faint embedded swirls from its initial application. No asbestos fibers in the mastic will be visible to the bare eye. While cutback mastic is not affected by water and many cleaners, if it is vigorously sanded not recommended, due to the asbestos riskit would become thick and tar-like from the heat. Containing between 15 and 85 percent asbestos, these adhesives were manufactured mostly in the first half of the 20th century.
However, some companies produced asbestos adhesives as late as Therefore, if your house was built or remodeled around or before, there is a chance that black mastic adhesive on your floor may contain asbestos.
Can Black Asbestos Mastic Be Safely Removed?
The Peterson Firm LLP, a Washington DC law firm that deals with mesothelioma cases, notes that the following companies manufactured adhesives containing asbestos:. Yes and no. It is safe if it is left alone and encapsulated, such as by covering it with new flooring. It is unsafe if it is abraded so that its fibers are released into the air. Asbestos is most dangerous in its friable state, in which tiny, light fibers float through the air and can easily be spread or ingested or aspirated by humans.
The only state in which asbestos is truly safe is when it is not exposed to an activity that may abrade it, such as sanding it or even walking on it over time. It is best if the old flooring covering stays in place and is covered with new flooring. Many types of flooring can be installed over old flooring, provided the old flooring is flat and well-adhered.
Unless a new floor is removed in the future, there should be no safety concerns about covering old black mastic. The worst thing to do is to attempt to grind it off with a drum sander or to scrape it off manually.
Because cutback mastic is thick, gummy, and difficult to remove, there is a practical way to get rid of it safely. Prominent brands of asbestos-laced floor adhesive include:. Read More.Read This]. View First Unread. Mastic over Redguard or laticrete If you were to water proof wallboard with either redguard or laticrete -could you use acrylicpro mastic over that? What do you guys think!! Sponsored Links. If it dries, it may well turn to mush when it gets wet. Mastic and waterproofing are a contradiction in terms.
I think once warm water and moisture get to the mastic, it can reimulsify causing it to fail, no matter what's under it, yes, the substrate would be protected, but not the tile itself from failing, that's what I think.
Also, Mastic cost more, and the fumes give me a headache. Dave's quicker than I am, what he said. If you are concerned about waterproofing it, you don't want to use mastic.
If you want to use mastic, don't bother with the waterproofing. Are you planning on trying this experiment on a customers house? What them others said, Mike. If you were fixin' to use mastic, why would you bother trying to protect the sheetrock?
You're gonna hafta tear out the sheetrock to do the replacement with thinset anyway, eh? My opinion; worth price charged. I just wanted to add this little story. I know mastic is useless in wet areas. Now, last week I find my trowel from the week before, and I forgot to clean it So I say" no problem, I'll just leave it in a pail of water overnight, and it will fall right off" It's been in there a week now and the mastic is still hard as a rock ok, a soft rock I'm sure if this was a pail of hot water it would be a different story It was mapie type one mastic.
Have they changed this stuff over the last few years? I still have the boards and I will put them both in water again an leave them till the mastic or thinset shows evidence of degrading - and report back here! Attached Images.
Can I Tile Over Painted Drywall?
Some of the Type I mastics do advertise theirownselfs to be perfectly usable in wet areas. I don't know if they've changed significantly in the last few years, but ol' Gobis doesn't seem to be impressed, and he gits to play with a lot of pookey down yonder at his schoolhouse I'm told. With all the new caulks and adhesives that have come to light in the past ten years, I really wouldn't be surprised if somebody comes up with something that really works. Nope, not surprised at all. Maybe I'm just looking at it from the wrong angle I realize that the point of your experiment wasn't to see which one "sticks to tile" better but to compare the effect of submurssion.
I concur that mastic can be a bear to get offa tools and such if left to 'cure.It is possible to tile over painted drywall, as long as the drywall is sufficiently prepared beforehand.
Preparing the drywall requires that the surface be roughed up with a sanding sponge prior to applying the mastic to adhere the tiles in place. When roughing up the surface of the drywall, a course-grit sanding sponge provides the best results.
Just run the sponge over the surface of the paint to break it up, applying just enough pressure to remove the glossy finish of the paint without breaking up the paper surface of the drywall beneath. By roughing up the surface, you give the mastic a better surface to grip, allowing it to sink through the paint and onto the drywall beneath.
Using the sanding sponge on the painted surface can result in dust particles, so it's best to cover adjoining areas with a drop cloth to ease cleanup after when the project is completed. After sanding the surface it's also necessary to dust off the drywall, to remove any remaining particles that may interfere with mastic adherence.
Wearing a mask during the sanding and dusting process is recommended to prevent breathing in paint particles, which can be hazardous to your health. Home World View.Water can find the smallest space in a bathtub or shower space and create a big stinky problem over time. He decided to completely remove the existing blue bathtub this blue must have been a popular color in ! The last post we put up about this project dealt with how we installed cement board.
We know this post will guide your bathroom renovation project in the right direction. If at any point you have a question or tip of your own, please type it in the comment section below. We love hearing about your projects! The last few posts about this bathroom remodeling project discussed hanging cement board to the bathtub wood studs. Cement board is the cheapest backer board for showers. And several Bathroom Repair Tutor videos show in depth how to use these materials.
Adding self-adhesive alkali resistant fiberglass tape to all the cement board seams is a really important step. The thin-set was the same kind used to adhere the tiles to the cement board panels and the consistency should allow it to just barely hang off a margin trowel or putty knife.
Smooth out the thin-set before it dries. We used a drywall sanding sponge to feather the thin-set because any ridges or bumps will cause the tile to lay unevenly. Use a level to check and fix any peaks or valleys. We also applied a thin layer of thin-set to all the screw heads in the cement board.
The thin-set will need to dry for about a day. This is especially true at the seams between two cement board panels or a cement board panel and existing drywall.
On this project it took a few passes with both joint compound and thin-set to get the cement board area suitable for tile. The prep work for RedGard is straight forward.
Since it does have a thick texture, RedGard should be applied only on the areas where there will be tile. Hydro Ban is also another option to waterproof cement board. Otherwise, the paint job of the adjacent wall next to the tile will look less than crappy and we mean this in the nicest sense.Elastomeric or liquid waterproofing membranes are one of the most convenient methods of waterproofing shower walls before installing tile.
I will refer to all the membranes as Redgard for the purposes of this post, but they all work nearly the same way. These materials can be installed with a regular paint brush, paint roller, trowel, or even sprayed on. They are applied to your shower walls then tile is installed directly onto it. When I use these products I always use a cement-based backerboard as the wall substrate without a plastic vapor barrier.
It is imperative that you do not install plastic behind your walls since this would create two waterproof membranes with your substrate between them. Having two barriers this close together leaves open the chance of trapping moisture between them with no way for it to evaporate.
6 Things NOT To Do When Building a Tile Shower
This may lead to mold. You must also tape the backerboard seams with fiberglass mesh drywall tape. The easiest way I have found to install Redgard is, after the walls are prepped properly, start with a paint brush and thoroughly coat all the corners and angles. You should be used to it after a few minutes. After all the corners are coated I use a paint roller and pan to cover the walls. Redgard is bright pink — I mean pepto-bismol pink, it almost glows in the dark. This is useful in that when it is dry it turns dark red.
The other membranes are similar. Just thoroughly coat the entire inside of your shower until the whole thing is bright pink — enough so it can be seen from space. You must then do a whole second coat the same way. Make sure the first coat has fully changed color before applying the second coat.
If you are using a roller Custom the company that makes redgard recommends that you roll on the first coat horizontally and the second coat vertically to ensure full coverage. Thanks for that Davis. Most of the product specifications for these materials state two coats to be sufficient, and it probably is.
I normally use three coats. Unless you have a steam shower or something similar, two coats would probably be enough. These products shrink a bit as they dry so you must make sure that it has not shrunk enough to create holes or voids in places such as corners and seams. You need a full coating for the product to be effective. When you are finished you should let the walls completely dry for a day before tiling.Tommy's Trade Secrets - How To Tile A Wall
Your tile can then be installed directly onto your walls over the membrane with a proper thinset mortar. When these products set they will create a rubber-like coating on your walls that is waterproof.
When used on shower walls it is a relatively quick, effective water barrier for your installation. These products can also be used as waterproofing on your shower pans in leiu of a regular pan membrane. Make sure your specific product includes specifications for this application if you choose to do that. Check the respective website for your particular product. I do know you can do this with Redgard, Aquadefense, and Hydroban. I also use these products for main or additional waterproofing on things like shower niches and concrete wall in basements, places where it is difficult to have a plastic vapor membrane behind the backerboards.
Basically any place that does not have waterproofing between the tile and shower framing. I always have Redgard with me. The versatility of these products make them a integral part of my shower waterproofing toolbox. The only drawback for these products, if you choose to look at it that way, would be the price.
They are a bit expensive. You may be able to get better prices by ordering online but make sure you take shipping costs into consideration.What is the difference between modified and unmodified? Which one does Schluter want you to use for Ditra and Kerdi?
Does it matter if your tile installer uses a medium bed for your large format tile? Alas, relief is here! Here is a breakdown of the terms and differences in thinsets so you can shop smart and purchase what you need. Therefore, this first post is going to examine the different terms that are used to describe thinset.
Liquid additives can be added to make these kinds of mortars into modifieds. The majority of thinsets on the market are modified. Most tiles 13 inches and under should typically use a thinbed mortar. Results will vary. Specialty thinsets: these are designed for specific applications. The new category name for these mortars is Large Heavy Tile mortar and we should start to see that term on bags in the future.
Quick question: Can ardex 77x be used over liquid latex waterproofing? Yes, it could be used for this purpose but Schluter now has their own line or mortarts that they would like you to use with Ditra-Heat.
I had severe skin burning and allergic reaction to Mapei Ultraflex. After 2. Weeks still peeling on hands and itchy rash all over my body. How can I make my own? Thanks Howard.
But it you can source thinset of any kind, modified or unmodified, them I would try to use that. It will be going behind a cooktop and a sink. Currently the thin VOG walls are painted. We have more movement in these homes than stick built. Also the cooktop and sink are very close to the walls. Not sure if we should use mastic or a flex thin set?
This will be our first tile project. Worried about grease behind cooktop and water behind sink. Thank you for all you do.Quality begins from the ground up. Preparing your surface is the most critical task of any tile or stone installation. Custom Building Products offers you one source for the needs of virtually any job. The foundation of precise tile and stone setting. Tile grout with dependable performance and color.
Look for tile grout with rock-solid durability, consistency and the largest color palette with Custom. Our grouts are easy to work with yet deliver hard, dense joints. Protect Yours Now! Stains on stone, tile or grout happen easily - and can leave permanent stains.
Protect your surface against both oil-based and water-based stains with the right sealer. Precision demands the best.
It bonds directly to clean metal drains, PVC, stainless steel and ABS drain assemblies and can be used as a slab-on-grade moisture vapor barrier under all types of floor coverings. Installation must comply with the requirements of all applicable local, state and federal code jurisdictions.
Exterior and wet areas must have proper sloping to drains. All surfaces must be structurally sound, clean, dry and free from contaminants that would prevent a good bond.
Newly prepared concrete must be troweled smooth and textured to a fine broom finish and cured for 28 days. Existing surfaces must be scarified and leveled, and all defects must be repaired. Do not bridge joints designed to experience movement. Carry these types of joints through the tile work. Clean the joint and install an open or closed cell-backer rod to the proper depth, as outlined in the Tile Council Handbook, EJ Next compress sealant into the joint, coating the sides and leaving the sealant flush with the surface.