What fill should we use to withstand the weight of an 800 lb. clawfoot tub?

QUESTION

We have a customer that has terrazzo in their home. We removed the tub surround and a closet area and there was no terrazzo underneath it, so it is at least a 1-1/2″ drop down that we need to fill before installing floor tile on top. We will be installing a very heavy claw tub on top of the floor tile. What do you suggest we fill the hole with that can withstand the weight of the tub that is at least 800 lbs.? Concrete would have to cure and my customer is not willing to wait the 30 or 60 days unless it is the only solution. Is there anything else we can use?

ANSWER

I suggest that a thick bed (mud bed/dry pack) would be the best alternative to fill the void. Most require a 72-hour cure time at the longest. Some pre-mixed versions can be tiled over (or have membranes applied) sooner. If using a wet-bed method, it is tiled immediately.

Details for installing a thick-bed method can be found in the TCNA Handbook. Use the Method Locator for Ceramic Tile near the back of the book to locate the Floor methods then find the type of substructure (i.e. wood framing), and you will be directed to the page number(s) for the appropriate methods. 

To waterproof or not to waterproof, that is the question

The TCNA Handbook for Ceramic, Glass, and Stone Tile Installation highlights the building designer’s responsibility to know how each tile installation will be used and maintained, to avoid under-designing an area for the amount of water it will be exposed to. Courtesy of the Tile Council of North America, Inc. (TCNA).

I talk to many people who are not clear on when and where to use waterproofing under tile installations. The most surprising thing I come across is those who think that tile, grout, mortar and backer board are waterproof. Unfortunately, there are many failed installations due to the lack of waterproofing and improper waterproofing, so let’s look at when to consider using waterproofing under tile.

A good place to start is the Tile Council of North America (TCNA) Handbook, which addresses waterproofing in several places. There are specific sections such as the “Membrane Selection Guide” and the “Wet Area Guidelines” that discuss membrane usage. The Membrane Selection Guide outlines several different types of waterproofing, from non-metallic, lead, copper, CPE and PVC. There are also the ANSI A118.10 trowel-applied sheet or liquid waterproof membranes commonly familiar to the tile trades. Sometimes these are referred to as fluid-applied membranes. Once cured, these ANSI A118.10 membranes are designed to provide a continuous membrane that tile can be directly bonded to.

The Wet Area Guidelines section in the TCNA Handbook is a very useful for understanding the requirements for waterproof membranes. In addition to discussing the environmental exposure classification, this section also discusses proper slope required for wet areas, as well as the different types of drains, such as clamping drains and integrated bonding flange drains. One of the most important topics discussed in this section is performing the water test, commonly called a flood test or 24-hour test. Testing the ability for the area to properly hold water is an important factor to know prior to installing tile and is required by certain municipalities.

Many TCNA Handbook methods include the possible use of a membrane, leaving the design professional to determine whether one is needed, based on the expected water exposure.

Within the TCNA Handbook methods, such as F141-19, the diagram shows the option for a membrane and below the diagram it states, “*Use of a membrane is optional. See membrane options.” Does that mean a membrane usage is optional at the discretion of the installer? No, first, it’s important to understand the designed usage of the space and its Environmental Exposure Classification. The Environmental Exposure Classification section in the TCNA Handbook is often overlooked and yet it holds a wealth of information with regards to the intended usage of a space and thus the proper classification. These classifications are divided into two categories, residential (res) and commercial (com). Both the residential and commercial categories are further divided into seven separate classifications, each with its own expected water exposure.  

In the example TCNA F141-19, the area is designed with limited water exposure has a rating of Res1,2/Com1,2. If this space is going to be used as a commercial kitchen for instance, this area is typically designed with limited

Commercial kitchen maintenance practices vary widely. Some are routinely saturated during cleaning and require a membrane.

water exposure in mind, giving it a Com2 usage rating. The difference could be as simple as how the space is cleaned, do they intend to hose down the walls and floor? If so, the area would need to be designed for increased water exposure as outlined in the membrane options within the TCNA F141-19. Typically, in this type of situation, the flashing connections to the walls and any drains need to be addressed to create a complete waterproof system.

As you can see, there are a lot of considerations for the proper selection and use of waterproof membranes. If you have specific questions, contact a membrane manufacturer and they can help with the correct choice of material. Some manufacturers even provide job site support for the proper installation of their material. I’ll leave you with my simple rule of thumb, if it’s going to see water exposure, waterproof it – because in the end it’s cheaper than a failure.

What is the best product to use to install resin-backed stone?

QUESTION

What is the best product to use to install resin-backed stone?

ANSWER

Epoxy is the safest choice. You could do a bond test with thinset to see how well it will adhere. Simply install a piece over concrete or concrete board, allow it to dry, and then see how well it is stuck. Some mortar manufacturers are making mortars they claim will adhere to resin-backed stone. If you have a relationship with a representative or a mortar manufacturer, they may have something they will warranty with it. Contacting the stone provider is always your first course of action. If you don’t get answers or test it, use epoxy. 

Negotiate and draft “pass through” clauses you can live with

Owners, contractors, subcontractors and lower-tier contractors must have a sound understanding of the operational details and triggers of “pass-through” provisions as their terms can significantly impact the obligations and risks of performing for lower-tier contractors. 

What is a pass-through clause?

Pass-through clauses (a.k.a. flow-down or conduit clauses), typically incorporate by reference the terms of a prime contract between owner and general contractor into a subcontract, thereby binding subcontractors to the same duties and obligations – and to the same extent – as the general contractor has to the owner. Pass-through clauses may use general “substantially as follows” or “substantially the same as” language, but, importantly they are not uniformly worded and can have the effect of imposing obligations never negotiated or contemplated by the lower-tier contractor. However, when drafted and used correctly pass-through clauses can provide protections to all parties by unambiguously flowing down specific upstream obligations of general contractors to the subcontractors who are actually performing the majority of the work. 

How are pass-through clauses implemented? 

It is in the owner’s interest to bind the subcontractor to the same obligations as the general contractor. For the general contractor, pass-through clauses provide a way of ensuring that subcontractors, suppliers and other downstream parties are required to comply with certain prime contract requirements. 

However, subcontractors may attempt to reject responsibilities flowing down to them when the pass-through terms lack sufficient clarity as to the subcontractor’s specific contractual and compliance obligations. Subcontractors will want to limit or reject overly broad pass-through clauses which – for example – make them assume responsibilities meant for other parties or that incorrectly excuse a prime contractor for its mistakes while still flowing down the responsibility for the mistakes to subcontractors. 

Other pass-through clauses may require that subcontractors be paid by the general contractor when the general contractor is paid by the owner. In such a scenario, a savvy subcontractor will want to reduce the risk of non-payment by negotiating and re-drafting terms to avoid limiting the subcontractor’s rights or remedies in the event of a claim or payment dispute. 

Subcontractors and contractors should work collaboratively to negotiate, revise or remove pass-through clauses that are of concern or to re-balance the risks. 

There are many other scenarios to which pass-through clauses can apply and where their effectiveness depends upon how well all parties can agree on their interpretation, such as: 

  • Who has authority to approve a change order, claim or delay notification and in what form it should be submitted, detailed, and supported by documentation? 
  • Who will have the responsibility for prosecuting a claim against the owner and how the recovery and attorney’s fees will be allocated – whether arbitration or litigation – and which parties will be required or permitted to participate? 
  • What happens if there are pass-through claims of subcontractors (i.e., claims the owner is responsible for) and claims that are only between the general contractor and a subcontractor? 

Importance of properly drafted pass-through clauses

As the “pass-through” language in prime contracts and subcontracts tends to “flow-down” damages, limits of liability or indemnification downstream – from the owner and general contractor level to lower tiers of subcontractors and suppliers – pass-through clauses become no less important than any other terms in a construction contract. 

It is essential that drafters review the prime contract and the complete set of the upstream documents in order to craft effective pass-through provisions. Moreover, well-drafted pass-through provisions should only include terms that already exist in the prime contract; and should not flow down the entire prime contract because doing so introduces contradictions with other subcontract terms. 

To assist parties with drafting pass-through clauses, The American Institute of Architects (AIA), in its A201™–2017 provides subcontractual relations language, used in owner-general contractor agreements, by which contractors can require subcontractors to be bound to the contractors by the same prime contract terms and to assume toward the contractor all the obligations and responsibilities that the contractor assumed toward the owner. It also allows subcontractors the benefit of all rights and remedies against the contractor that the contractor – by the prime contract – has against the owner, and requires the contractor to identify to subcontractors any terms and conditions of the subcontract that may be at variance with the prime contract documents.

Similarly, the AIA’s language establishing the contractual relationship between contractor and subcontractor in the A401™–2017, which cross-references A201–2017, passes “the duties and responsibilities of the Contractor under the Prime Contract to the Subcontractor with respect to a portion of the work designated in the completed A401–2017 document.” 

The enforceability of pass-through clauses in complex construction agreements often hinges on the perceived clarity or ambiguity to both upstream and downstream parties. In order to avoid unintended legal or financial consequences the critical drafting process should be assisted by professionals experienced in commercial law and construction law and with accessibility to all of the upstream and downstream documents.

Pass-through interpretation and enforceability can vary by state

The location of the project plays a significant role in how pass-through language may be interpreted and enforced. Therefore it’s important to understand the nuances of applicable state laws when drafting and implementing pass-through clauses. 

For example, in New York, courts have held that general “incorporation clauses” in a subcontract can only bind a subcontractor to the “scope, quality and manner of the work to be performed by the subcontractor.” While many states take the New York approach, other states do allow a generalized “flow down” of obligations via “incorporation clauses.” And still other states construe all contract documents, including the prime contract, subcontract and all exhibits, together in an effort to harmonize and give effect to all of the provisions of the contract so that none will be rendered meaningless.

Pass-through best practices

Below are a few other examples of best practices that should be considered when reviewing or drafting pass-through provisions:

  • Negotiate pass-through terms at the pre-bid stage so that the costs/benefits of undertaking flowed-down obligations may be factored into bids. 
  • Parties should work collaboratively to address gaps in risk-shifting or risk-sharing and develop acceptable levels of risk. 
  • Limit the requests for pass-through revisions to a small group of terms or issues (and not to the prime terms) to increase acceptance. 
  • Avoid using general “incorporating by reference” language that can be misinterpreted to merely incorporate prime contract for a limited purpose. 

Toolbox Talks for Quarriers Available in Natural Stone University

Oberlin, OH, November 20, 2019—The Natural Stone Institute, in coordination with the National Building Granite Quarries Association (NBGQA), has added three toolbox talks for quarriers to the Natural Stone University. Topics include the following:

  • Fall Arrest System Regulations
  • Highwall Management and Use of Drones
  • Quarry Slab Tipping Safety

There are now a total of 27 quarry-specific toolbox talks available in the University, covering topics ranging from personal health and human safety to the safe use of equipment such as wire saws and preventing silicosis.

Natural Stone Institute Logo

The Natural Stone Institute, in coordination with the National Building Granite Quarries Association (NBGQA), has added three toolbox talks for quarriers to the Natural Stone University.

Mike Loflin, Industry Research & Information Manager for the Natural Stone Institute commented: “These quarry-specific resources are an important addition to our library of safety resources. The information provided is the cumulative work of the NBGQA safety committee. The NBGQA safety committee consists of some of the most talented safety officers, operations managers, and human resources professionals in the natural stone industry. Over the last several years, the committee has identified issues and provided seriously needed safety solutions for the quarry sector of the dimension stone industry. We are proud to partner with NBGQA to present these resources free of charge to the industry through the Natural Stone University.”

 

To access these toolbox talks and other educational resources, visit www.uofstone.org. To learn more about the National Building Granite Quarries Association, visit www.nbgqa.com.

 

 

How to remove stains from pavers

Question

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?

Answer

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

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.

Safety

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. 

 

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 4.3.8.2 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”.

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

Question

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?

Answer

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

(continued)

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.

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