How to remove stains from pavers


I have a client with peacock pavers. They had a large mat in front of their door with two planters on either side if it. The planters leaked onto the mat and drained off the porch, but the dye from the mat has left a bad stain on the pavers. Any recommendations on how to pull those stains out?


2019-20 NTCA Reference Manual

I would contact a company that makes sealers, grouts, and related products and ask them if they have a product that will work to dissolve the minerals that leached in from the planters. Some setting material manufacturers also make products like these. If you know which company made the grout and/or thin-set, they would be the logical choice to ask first.

Do you have a copy of the NTCA Reference Manual? In the manual, there is a section dedicated to processes to remove stains from tile and stone. A quick browse through the table of contents will point you to this section that will provide tips and tricks that may help remove stains like these.

– Mark Heinlein,
NTCA Technical Director

About that grout joint width

There are many factors to consider before selecting an appropriate grout joint width for porcelain and ceramic tiles. Factors that affect proper specification, by way of example but without limitation, include the tile’s dimensional tolerances such as allowable warping and out of square per ANSI A137.1 manufacturing standards, floor flatness, size of the area being tiled, and the presence of movement joints in the subfloor per ANSI A108 installation standards. One also needs to consider exposure to excessive moisture, direct sunlight and temperature swings based on the final use and application. Both vertical and horizontal applications can be affected by all of these factors, which in turn can cause movement and tension in the finished tile assembly. 

There is a general misconception that because ANSI A108 sets its minimum recommended joint width limit to 1/16” – and grout manufacturers produce grouts that can be applied as narrow as 1/16” – that the minimum suitable joint width can also be set to 1/16” for all application types. In some applications, like a kitchen backsplash, a narrow joint may be attainable. However, selecting an arbitrary floor grout joint width as narrow as 1/16” for purely aesthetic reasons, or perceived maintenance, can be extremely problematic not just in terms of the tile assembly’s structure, but also may not be attainable across large areas while keeping adjacent rows aligned. There have been great advancements in manufacturing technologies of both cementitious and non-cementitious grouts as well as grout additives over the years, allowing highly stain-resistant properties to prevent, and in some cases eliminate, the age-old struggle with keeping grout joints clean. 

Manufacturers sort tiles by caliber. Tiles of the same size are closer in caliber.

It is not only important to understand the intent of industry and manufacturers’ recommendations prior to joint width specification, but also understand the function and necessity of grout in a tile application as a whole prior to selecting a joint width. The role of grout is not only to bond adjacent tiles to one another, but also absorb and disperse some of the tension caused by the expansion and contraction of tiles and substrates. Although grout should not be used as a standalone waterproofing measure, it does display repellent properties, that when compromised in a wet application, can lead to other failures. In other words, if the joint width is not filled properly, maintained properly, or of sufficient width, then failures may be inevitable. As such, butt-jointing techniques should never be used. 

ANSI industry standards for tile are written in such a way to account for both manufacturing and installation tolerances to mitigate potential failures and set expectations of what the end result may look like. When going against industry standards and/or manufacturers’ recommendations, failures may include excessive appearance of lippage, cracking, warping, bond failures, water damage and tenting from tension. Provided that the manufacturer and/or distributor that the tiles were purchased from follow ANSI, ISO or other industry standards for manufacturing, then it can be presumed that the tiles supplied will have certain flatness and dimensional tolerances within a particular range. Since these standards allow for facial dimension variations, the joint width needs to properly account for these variances so that grout joint centerlines can remain straight throughout the application and adjacent tile modules don’t touch at any point. The joint width itself may narrow and widen throughout the application to account for facial variations and floor flatness. ANSI A108.02 Section 4.3.8 addresses this by stating the joint width shall be three times the actual variation of the facial dimensions of the tile supplied. 

A larger grout joint is needed for tiles that do not meet the rectified requirements, especially in an offset pattern.

One critical point that is often missed in ANSI A108.02 is the additional verbiage that recommends widening the joint of necessity past the standard recommendation to accommodate the specific tile being installed. Without having to measure each tile, it is always best to account for the maximum allowable tolerances whenever possible during specification, which would be approximately 3/16” for pressed porcelain and ceramic tiles and approximately 1/8” for rectified products. This is just a general guide. In some instances the variations in tile dimensions will be minimal, while in other cases they may be riding the maximum tolerance limits or beyond. For example, glazed red-body ceramics are typically developed as a budget-friendly product and may require up to 1/4” joint width depending on the manufacturer’s recommendations instead of the standard recommendation of 3/16” for pressed ceramics due to their inherent size irregularities. With the rise in popularity of long porcelain planks, even though the edges of such tiles may be rectified and the tiles may not have any wedging, the widening of the grout joint width may be necessary to address any inherent warpage that those products tend to display along an edge or diagonal due to their elongated shapes. As such, it may actually be best to install some rectified plank products with a 3/16” joint instead of the generic industry recommendation of 1/8” to help hide any inherent lippage. In other words, due to nuances of manufacturing of certain product types, the manufacturer’s recommendations always prevail over a generic industry guideline to achieve the best end result. 

The final layer that provides guidance in proper grout joint width specification is the advancements and availability of leveling clip systems on the market today that help mitigate against the possible negative effects of tile and substrate flatness. Not only is a clip system used as a spacer, but the wedges’ function is to pull tiles from below and simultaneously push tiles down from the top to create a flatter plane in the finished tile install. When potential lippage and floor flatness are being addressed in this manner, a tighter joint may be achieved provided no other jobsite conditions, as previously mentioned, will negatively affect the floor. When opting to go against industry standards or manufacturer recommendations, especially when using a leveling clip system, the specifier and end user must have an understanding, not only of the inherent nature of certain tile product types, but installation tolerances as well. Leveling clip systems are not a final end-all solution to problems related to inherent warpage and joint width spacing, but they do provide an effective measure to mitigate against the negative effects of lippage and challenges in floor flatness. 

Narrow joints are possible, but only when the tile is well within the sizing and warpage tolerances for rectified tile. Even so, an offset pattern was not selected because a straight lay masks tile warpage (minimizes lippage) whereas an off-set pattern would have highlighted the tile’s warpage by causing greater inherent/unavoidable lippage in the installation, which would be particularly visible when natural light shines in on the installation. Also, the grout closely matches the tile, making the joints seem smaller/less obvious. Even with all of these factors, the grout joints are 1/8” wide, not 1/16”.

Creating a great culture could be your best retention strategy

Results from the People in Construction 2019 study

A recent survey asked several hundred construction professionals across all trades about leadership and culture in their firm. We didn’t ask, “Are you having trouble finding people?” We asked, “Are you happy at work? Do you feel trusted?”

In some ways, construction is just like any other industry. There are precious few exemplary companies, too many abysmal ones, and sadly, most are pretty darn average. But, average is not a retention strategy. Creating a great culture might be the best profit strategy. There is a direct correlation between great workplace culture and increased profitability.

Who responded in the People in Construction 2019 study.


Every contractor says “people are our most important asset” but talk is cheap. Even cheaper when it comes to safety. It is encouraging that 90% of all respondents reported safety as a top priority. 97% of office operations and 93% of field supervision did say safety was a top priority. The really bad news is in safety execution. Only 68% of field supervision could say they consistently work safely. That’s approximately one in three field supervisors admitting they don’t prioritize the safety of their employees. Things are slightly better in the office, with 78% reporting that they consistently work safely – but the gap between what is said and what is actually done is alarming. 

The field/office divide

This gap between field and office persists in other areas. Construction has always dealt with the field/office divide. This is the acknowledged challenge in geography and culture that creates distance and tension between project management in the office and field supervision on the jobsite. Research confirms the divide is now a chasm. The difference in perception between field supervisors and project managers is stark, and provides a major opportunity for dialogue, collaboration and unity. Any effort to bridge the chasm is worth it. 

In answering the question, “I am able to maintain a reasonable work-life balance,” only 50% of field leaders said yes while 83% of office operations said yes. Only 62% of field leaders agreed that leaders live by the core values of the organization but 83% of office personnel agreed. Research confirms that having a close friend at work increases loyalty and commitment. It is alarming then that only 50% of field leaders could say yes to this question, with the office at 83%. While the causes of the chasm may be debatable, it is undeniable that it is detrimental to profitable execution.

The office-field chasm in People in Construction 2019 study.

The difficulty of implementing change

Musician Sheryl Crow sang that “a change would do you good,” but the majority said attempts at change often fall short. On this question, the executives confessed to these failings at a level of 73%. If leadership is about change for better results, it is troubling, perhaps even depressing, that three-quarters of senior leadership (those who come up with the idea and whose job it is to spearhead the change) say their efforts fall short. This signifies a huge opportunity for those who can crack the code on implementing change. Here are the CliffsNotes: It takes longer than you think, and it requires a significant personal investment from leaders to sell the change. This “personal selling of change” is the fastest way to build trust, leverage relationships, and troubleshoot potential problems.

All is not lost; there are people who will step up. One-third of all respondents said they had more to give when asked if they were working at full capacity! These people are saying they could do more! They are not overworked; they are under-challenged. This leads to disengagement. This finding underscores the idea that, rather than blaming the employee for performance or discipline issues, perhaps the supervisor should be evaluated first. 

There is no single solution to improve culture. The number one reason people stay in a job is a good relationship with their immediate supervisor. People don’t work for an industry, they work for a supervisor. What any reader can do is look inside their own organization and ask these questions to see how they compare. Very few firms attain “Best in Class” distinction. Over 90% of employees must respond and say the culture is a great place to work to be confident it is true, but a firm need not be best in class today to be better tomorrow. 

Efforts and actions that build trust are essential. Leaders living up to commitments and sincerely talking with employees build trust. Helping people feel they are in on things and giving candid feedback build loyalty. All of these actions must be consistent and sustained. 

Excellence isn’t a program, it is a way of life. Creating a great culture is an all-hands effort that starts with key leaders across all levels of the organization working together to execute a coherent human capital strategy. 


Is the drywall installer or tile installer responsible for the joints/corners?


We have a project with wall tiles that are 4” x 40”, 8” hex and large 24” x 47-1/8”. The general contractor has drywall figured and states that joints or corners shouldn’t have to be mudded/done by the drywall installer nor primed! Our tile installer said that he wants the joints and corners completed and everything primed before he will install. These areas are not in a wet area. However, the large tile is at a fireplace wall.

What is correct?


TCNA Handbook Methods (l.) W242 and (r.) W243.

There are two recognized methods for installation of tile over gypsum board found in the Tile Council of North America Handbook. They are methods W243 (thin-set) and W242 (organic adhesive). Both have a section of the method that are titled “Preparation by Other Trades”. In that section it states gypsum board shall be installed per GA 216 “treated with tape and joint compound, bedding coat only (no finish coats). Nail heads one coat only.”

To my understanding primer is not needed. We do recommend slightly dampening the surface of the drywall to help ensure the board does not prematurely draw the moisture out of the thin-set bond coat.

– Robb Roderick,
NTCA Technical Trainer


Q: Would you say primer is the responsibility of the tile installer or drywall installer?

A: If we are going to put tile onto the drywall surface and the primer is necessary to prepare the drywall for a successful tile installation, this would be the responsibility of the tile contractor and not the drywall contractor.

Protecting your investment in Mother Nature with TLC

When working with natural stone, all the rules you know about porcelain tile can be immediately discarded. It’s imperative to know the stone, know the finish, know about the stain, and know what you are getting into. What works for porcelain tile does not necessarily apply when working with products created 100% by Mother Nature.

The Natural Stone Institute states that natural stone can be classified into two general categories according to its composition: siliceous stone or calcareous stone.

Understanding the key differences between these can help avoid costly damage to the product and to your reputation as a knowledgeable contractor!

Types of stones

Acid etching in Veona Rosso.

Calcareous stone is composed mainly of calcium carbonate. These stones include marble, travertine, limestone and onyx and can be classified as acid-sensitive. They are sensitive to acidic substances such as coffee, lemon juice, vinegar, and bleach, all of which can very often leave a natural stone surface etched.

Common sense dictates that by using acidic cleaning products, acid-sensitive stones could very well become damaged. Therefore, these stones should ONLY be cleaned with a neutral cleaner! Before applying any product, always test it on a section of stone not being used, or an area that will not be in plain sight.

Etching on marble counter.

Non-calcareous (siliceous) stone is composed mainly of silica or quartz-like particles. Types of non-calcareous stones include granite, slate, sandstone and quartzite. For the most part, these stones tend to be very durable and most are acid-resistant. Be advised, some of the more exotic stones have veins of calcium calcite, which can make them acid-sensitive. Whereas acid-resistant stones can generally be cleaned like porcelain tiles, I recommend to always test first via the small aforementioned exercise.

Now that you know your stone, let’s discuss the surface finish of acid-sensitive stones.

  • Honed finishes on acid-sensitive stones can withstand alkaline cleaners. 
  • Polished acid-sensitive finishes can be dulled by strong
    alkalines; again neutral cleaners are the best option.
  • Testing is ALWAYS your best option.

Removing stains without harming the stone

Rust stains on marble.

Let’s review a few types of stains. Identifying the type of stain on the surface is the key to ultimately removing it without harming the stone. Refer to the manufacturer labels when choosing the right cleaner for your stone and the stain.

Organic stains: These are caused by organic products such as fruit, tea, dirt, leaves, wine, cooking oil, and even animal droppings. Other stains can occur due to the growth of fungi, algae, mildew and other microorganisms. Generally speaking, these types of stains appear on outdoor pavers or inside a bathroom/shower stall and other wet areas.

Carrara marble with rust.

Inorganic stains: Paint, cementitious grouts, cements, rust, soap scum and other non-organic sources can cause serious staining to natural stone features, especially if not cleaned up quickly.

Preventing and removing grout haze

Last, let’s discuss grout haze on natural stone. One of the top, vexing problems is cementitious grout haze on acid-sensitive stones. 

How do we prevent grout haze on acid-sensitive stones? The only way is to always seal the stone, BEFORE grouting. This is a vital, cardinal rule – always seal an acid-sensitive stone before grouting. The use of a normal sealer will suffice.

Cement residue on stone.

What do you do if grout haze does appear on an acid-sensitive stone? Here, we need to work with a neutral cleaner and the mechanical action of scrubbing. Scrubbing is important. If the stone has a natural finish or is honed, you can use an alkaline cleaner to remove an epoxy residue. 

Before and after marble cleaning.

From granites to limestone, from marbles to slate, Mother Nature has truly created some of the most beautiful surfacing material on our planet. We’ve pulled it from the earth and brought it to life through exquisite tiles and slabs, which adorn our floors and walls across the globe. Keeping stone material in its most beautiful state takes just a few simple steps to understand what you are working with, and then learning the proper protocols to bring them back to that beautiful condition. Taking simple steps to read the recommendations, using the right products and not skipping any steps in doing so can ultimately mean that customers are happy, there will be more money in your pocket, and chances to be called back on a regular basis are optimized.

How to ensure a successful self-leveling underlayment application 

“Self-leveling underlayment” is a bit of a misnomer because it requires the intervention of a thoughtful installer to ensure the best results. Follow these guidelines to prevent issues in your self-leveling underlayment installation.

1. Select a product appropriate for the installation: Know your installation environment and familiarize yourself with the relevant ASTM standards for strength. A commercial floor subject to heavy rolling loads will require a higher-grade self-leveling underlayment than a floor in a single-family home.

Also, it is critical to understand your project timeline and choose a product that fits within the appropriate schedule. Some products may require 24-48 hours prior to installing tile, while other more premium products are ready to accept flooring in as little as 2-4 hours. Consult product data sheets for information on tensile strength, compressive strength and flexural strength, as well as recommended cure times.

2. Stabilize your substrate: Most products require that all surfaces are fully stable and structurally sound prior to the application of a self-leveling underlayment. For example, wood must be securely fastened with screw-type or ring-shank nails and adhesive because if it shifts, it could cause cracking. 

3. Prepare your substrate: Make sure to plug all floor openings, gaps and cracks and install termination dams to prevent any seepage. Consult with product manufacturers to determine moisture limitations of the self-leveler, adhesive and flooring to determine if moisture mitigation is needed.

If moisture mitigation is required, this must be done prior to installation of the self-leveling underlayment.

TEC® Level Set® 200 was designed for the fast leveling of floors. It is both pourable and pumpable to fit your job needs.

Self-leveling underlayments (SLUs) require the use of a primer prior to installation. Primer retains the moisture within the self-leveling underlayment to properly cure. Secondarily, it acts as a bonding agent to ensure the SLU bonds properly to the substrate. Refer to the primer label for information regarding application methods and dilution per ASTM F3191.

Beyond priming, most self-leveling underlayments require that the substrate be free from any contaminants that may inhibit bond, including oil, grease, dust, loose or peeling paint, sealers, floor finishes, curing compounds or contaminants. Some underlayments will require a certain concrete surface profile (CSP), and in these cases, mechanical abrasion, like shot-blasting, is required. Make sure the substrate is contaminant free and has the necessary surface profile before starting the pour. 

4. Mix properly: Mix your self-leveling underlayment within the water range specified on the bag. Overwatering will lower the strength of the underlayment and can cause cracking and pinholing. Additionally, a white film (efflorescence) may form on the surface of the cured underlayment if the product is overwatered. This film can act as a bond breaker if the mortar bonds to the salts instead of the SLU. Do not over mix it, as this can make it harder to work with and lead to cracking or improper flow. Mix a maximum of two bags at a time when barrel mixing to ensure a proper blend. Follow equipment and product manufacturer’s recommendations when pumping self-leveler.

TEC® Level Set® 200 is walkable in 3-4 hours, making it a great choice for fast turnaround jobs.

5. Be aware of product and environment temperature: Make sure that the temperature of the room is within the manufacturer’s acceptable range. A climate that is too cold or too hot can cause issues, such as increased set time in cool temperatures or reduction in heal time in hot environments. Temperature and humidity will affect flow, working time and set time.

Additionally, the temperature of the powder and the water is crucial. Leaving product in the sun, or in a hot environment may lead to flash setting. In situations where warm product is unavoidable, mixing with cool water may help combat installation issues. 

Whether the environment is warm or cool, acclimating the product prior to mixing is a best practice.

TEC® Level Set® 200 delivers extended 25-35 minute working time without compromising flooring installation time.

6. Use as recommended: Manu-facturers will specify the maximum thickness of their product. Some products allow for addition of aggregate to increase the depth of the pour, while others only allow their product to be used neat. Be sure to use the appropriate aggregate size and amount when extending a self-leveling underlayment. If a surface is extremely uneven in an isolated area, a patch may be necessary, rather than a self-leveling underlayment. Consult with manufacturers to determine the most suitable product for your application. 

Protect from excessive drying due to air movement. Use of fans or other direct air flow is not recommended, as the surface can be prematurely dried, leading to a weak underlayment.

7. Protect your underlayment: Generally, underlayments are not final wear surfaces. They should be protected from construction trade traffic until final floor covering is applied. Traffic without protection can lead to cracking and disbonding. Do not allow heavy or sharp metal objects to be dragged directly across the surface.

A common theme connects these recommendations: noting and adhering to the manufacturer’s instructions. You must read labels and product data sheets carefully to ensure products perform as desired. If you do have questions, you can always reach out to the product manufacturer.

How small is a small business? The answer could cost you money!

Are you a small business? That depends on whom you’re asking.

Lots of people I know define a small business in lots of different ways, with the most common being revenues and number of employees. For the most part, it’s really not that important. “Small” is in the eyes of the beholder.

However, if you’re one of those businesses looking to get government contracts or loan guarantees from the US Small Business Administration (SBA), the definition of “small” really is important. That is why a recent announcement by the SBA may have an effect on your livelihood.

This summer, the SBA announced a proposed rule to modify the method for calculating annual average revenues used to determine how big a small business is. Why the fuss? The calculation figures into whether a business is eligible to receive federal contracts and loan guarantees. Currently, the calculation uses a three-year revenue average. The proposed rule will up that to five years.

Congress may actually get something done – and give a boost to retirement plans 

The announcement comes on the heels of 2018’s Small Business Runway Extension Act, which requires service businesses to average five years of revenues. Now, all businesses will be subject to that requirement. This is the first step of the implementation.

So is this a good or bad thing? 

The federal government believes it’s a good thing, as do some experts. “In most instances, this will give small businesses more time to compete in small business set-aside procurements,” write Suzanne Sumner and Erin R. Davis of the law firm Taft Stettinius & Hollister LLP. “The new five-year calculation will also allow those small businesses with an outlier year of significant revenue more time to sustain the growth and prepare to compete in unrestricted competitions.”


That position makes sense. But there are a few things about this that give me pause.

For starters, I don’t like using revenues as a basis for determining whether a business is “small.” I have a few clients, for example, that generate big revenues because they sell large machines or property but each has fewer than 10 employees. They’re small, but not in the eyes of the SBA. I would prefer the rule to include other factors, such as the number of people (and perhaps contractors) employed, to really determine the size of a business.

I’m also concerned that a growing small company might find itself excluded from federal work as a result of a couple of good years. Or that larger companies that have had a bad year or two might find themselves classified in the “small business” category, at the expense of small businesses already there and competing for work.

If there’s one thing I’ve learned from running a small business, it’s that you can’t apply a simple revenue formula to determine if a business is indeed small. Other factors should be considered. Sure, it might take a little more time or add more complexity. But we’re talking about the difference between a qualified company getting the help and opportunities it deserves from the government, or potentially failing.


This article originally appeared on July 2, 2019 in The Guardian at A past columnist for The New York Times and The Washington Post, Marks now writes regularly for The Hill, The Philadelphia Inquirer, Forbes, Inc. Magazine, Entrepreneur Magazine and Fox Business.

Should there be 1/8″ gap when using an uncoupling membrane


We’re going to use an uncoupling membrane on a wood subfloor. I know when it’s a brand new subfloor there should be a 1/8” gap. This house has had the subfloor in place for the past 10 years. Do I still need to cut the 1/8” gap? 


It is a best practice to have the gap in place between the wood (i.e. plywood/osb). Although the wood structure has been in place for 10 years, it has likely expanded or contracted over those years and may do so again. The uncoupling membrane will likely protect from that expansion and contraction but I suggest following the best practice of opening up the gap.

It’s pretty easy to do. Set the depth of a circular saw to about 3/16”-1/4” deep (just deep enough so you don’t cut the wood tongue off) and run the saw down the joints between the sheets. Use a good carbide tipped blade that will give you about a 1/8” kerf or cut width.

For the ends of the runs near the walls, use an oscillating tool to finish opening up the gap.

Mark Heinlein,
NTCA Training Director

Can grout and sealant be mixed together?


Can grout and sealant be mixed together so you don’t have to seal the grout when it’s done?


Sealers are not designed to be mixed with grout. Sealers are designed to be applied to cured cementitious grout. 

There are two basic categories of sealers. They are generally designed to either penetrate the surface of the cured grout (penetrating sealer) or to cure as a sacrificial layer on top of the cured grout (topical sealer).

There are admixtures that are specially formulated and designed to be mixed with cementitious grout. These admixtures are usually designed to replace the need for sealers.

There are a wide variety of grouts available. Some are considered ready-to-use and likely do not require any sealing at all. Some powered grouts are formulated with sealers already in the dry mixture.

I suggest you contact the manufacturer of the grout you are using to determine its properties and whether a sealer is recommended for use with it. 

Mark Heinlein,
NTCA Training Director

Who determines construction joints?


We are on a job won by a flooring contractor who will install sheet vinyl or porcelain tile on a concrete floor. We are trying to determine who identifies where the construction joints are and how they will be treated, if it is not provided in the drawings.


The person with knowledge of the building and structure has to identify where the joints are and how they will be honored or treated depending on the type of joint. 

If there are drawings and specifications for the job, the professional that analyzed the structure to ensure adequacy for a tile installation and who drew up the specifications is the person responsible for providing the tile installation contractor the drawings for location and identification of honoring / treating the structural joints.

You can refer them to TCNA Handbook method EJ-171 where this is further defined. 

Mark Heinlein,
NTCA Training Director

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