Stucco and Concrete bonding agents

Summary

Kirk Giordano, a seasoned plastering expert, discusses the proper use of Weld Crete, a bonding agent for stucco applications. Drawing on over 30 years of experience, Kirk explains why he sometimes dilutes Weld Crete, despite the manufacturer's instructions, particularly for color coat applications on painted surfaces. He shares valuable tips, emphasizes the importance of proper preparation, and warns against common mistakes like over-applying bonding agents or mixing them with stucco. Kirk advises homeowners to follow the can's directions and seek professional help for stucco color coats to avoid potential failures.

Takeaways

• 👷 Weld Crete is a popular bonding agent used in the plastering industry, especially for adhering color coats.
• 🚫 Despite the label warning against dilution, Weld Crete can be diluted for specific applications, such as color coats over sealed surfaces.
• 🏗️ Weld Crete is typically used full strength for applications like concrete to concrete bonding.
• 🎨 A color coat is much thinner (1/8 inch) compared to stucco, which may be half an inch or more.
• 💧 Diluting Weld Crete can be done in a ratio of two parts Weld Crete to one part water, but it should be done with caution and experience.
• 📅 Weld Crete can be applied and then stucco or cement can be applied within an hour, and it remains effective for up to 10 days.
• 🏠 For older houses with multiple layers of paint, applying Weld Crete full strength can lead to spider checking in the color coat.
• 🚿 A clean surface is essential for the bonding agent to work effectively; dust, dirt, or mossy surfaces will prevent adhesion.
• 💡 Kirk recommends against adding bonding agents directly into the stucco mix for a color coat application, as it can cause the finish to fail.
• 🌟 Weld Crete is praised for its strength and reliability, being one of the strongest liquid bonding agents used by experienced plasterers.
• ⚠️ It's advised to follow the instructions on the can and consult with a licensed plastering contractor for color coat applications.

Q & A

What is Weld Crete primarily used for?

Weld Crete is primarily used as a bonding agent for adhering color coats of stucco to sealed or painted surfaces, as well as for bonding concrete to concrete.

Why does Kirk dilute Weld Crete when applying color coats?

Kirk dilutes Weld Crete when applying color coats because using it full strength on well-painted surfaces can lead to spider cracking. Diluting helps the stucco color coat to adhere properly without over-sealing the surface.

What is the recommended thickness for a stucco color coat?

The recommended thickness for a stucco color coat is 1/8 of an inch.

Why does the label on Weld Crete say 'do not dilute'?

The label on Weld Crete says 'do not dilute' because it is engineered for bonding concrete to concrete, where full strength is necessary to create a strong bond over sealed or painted surfaces.

What can happen if Weld Crete is applied too thickly or full strength for a color coat?

If Weld Crete is applied too thickly or full strength for a color coat, it can lead to spider cracking because the wall loses its ability to absorb moisture properly, causing the stucco to dry unevenly from the outside in.

What are some other bonding agents Kirk mentions besides Weld Crete?

Kirk mentions Sika products and Quikrete as other bonding agents that can be used for stucco work.

Why should bonding agents not be mixed into the stucco material?

Bonding agents should not be mixed into the stucco material because they will be diluted to the point of ineffectiveness, leading to poor adhesion and causing the stucco to peel off in sheets within a few months.

What should be done before applying a bonding agent to ensure good adhesion?

Before applying a bonding agent, the surface must be clean, free from dust, dirt, or moss, as bonding agents will not adhere properly to a dirty surface.

How does Kirk recommend applying Weld Crete for color coats?

Kirk recommends applying Weld Crete lightly and diluting it with water (e.g., two parts Weld Crete to one part water) when using it for color coats. It should be applied using a brush, roller, or airless sprayer, depending on the project.

What is the potential consequence of not using the proper dilution of Weld Crete for a painted surface?

If the proper dilution of Weld Crete is not used on a painted surface, the stucco color coat may spider crack due to inadequate absorption of moisture by the underlying surface.

Outlines

00:00

🛠️ Discussing Weld Crete Usage and Best Practices

Kirk Giordano shares insights about using Weld Crete, a bonding agent primarily used for stucco applications. He provides a background on his experience with the material dating back to the 70s and explains the importance of diluting Weld Crete in certain scenarios, despite the label advising against it. He highlights how he and other contractors have successfully diluted the product for specific jobs, particularly when applying color coats (1/8 inch thick) over surfaces like sheetrock and cementitious boards. He emphasizes the importance of following the instructions on the can but also shares his 35 years of trade experience and techniques for achieving long-lasting results.

05:06

💡 Practical Advice for Homeowners on Bonding Agents

Kirk recalls a story where a fireman wanted to save money by applying Weld Crete himself. Kirk advised him to dilute the product, but the fireman applied it too thick, which would cause issues like spider cracking when the stucco color coat was applied. He stresses the importance of not over-applying bonding agents and recounts another instance where a contractor didn’t apply enough, resulting in a redo. Kirk concludes by advising homeowners to leave the application of bonding agents to professionals to avoid complications.

10:11

🧱 Explanation of Bonding Agent Effects on Different Surfaces

Kirk explains how different surfaces like sheetrock and cementitious boards absorb moisture at different rates, which affects the application of stucco. He uses La Habra finish coats with medium sand grit to show how surfaces with suction properties won’t spider check. He explains that bonding agents must be applied according to the manufacturer's instructions to avoid issues like moisture being trapped, leading to spider cracking. Kirk also demonstrates how different surfaces react to stucco application and how important it is to understand these factors for a long-lasting finish.

15:13

⚠️ Warnings About Misuse of Bonding Agents

Kirk recounts a story of a homeowner who chose a cheaper contractor, only for the stucco finish to start peeling off in sheets because the bonding agent was either applied over a dirty surface or mixed into the stucco, which is incorrect. He warns against adding bonding agents directly into a stucco mix, as this will cause it to fail within six months. He advises using bonding agents only as intended, particularly for maintenance-free finishes, and emphasizes that improper use of these products can lead to costly repairs.

🎥 Conclusion and Final Thoughts on Stucco Application

In the conclusion, Kirk reflects on the incredible strength of Weld Crete, a bonding agent capable of holding thick layers of stucco to vertical surfaces. He admits that he doesn't fully understand the chemical composition but emphasizes its effectiveness. He warns against diluting the product too much and recommends leaving this work to licensed contractors who know the nuances of each job. Kirk wraps up the video by thanking viewers for their support and encourages them to like and subscribe to his channel for more informative videos.

Keywords

💡Weld Crete

Weld Crete is a bonding agent used in construction to help materials like stucco or cement adhere to surfaces. In the video, Kirk emphasizes its role in adhering stucco to both painted and sealed surfaces, particularly when diluted depending on the surface. He mentions its importance in ensuring proper adhesion, especially for color coats, and warns against improper use like applying it too thick, which can cause issues like spider cracking.

💡Color coat

A color coat is a finishing layer applied to stucco surfaces that adds both color and texture. Kirk explains that color coats are typically about 1/8 of an inch thick and require proper preparation, including the use of bonding agents like Weld Crete. He also cautions that improper application, such as not diluting Weld Crete on painted surfaces, can lead to problems like spider cracking due to uneven drying.

💡Dilution

Dilution refers to the process of mixing a bonding agent like Weld Crete with water to achieve a thinner consistency. Kirk often dilutes Weld Crete to ensure the proper application on various surfaces, particularly when dealing with thin layers like color coats. He emphasizes that while dilution is his practice based on experience, users should follow manufacturer instructions.

💡Spider cracking

Spider cracking occurs when a stucco color coat cracks in a web-like pattern due to improper drying. Kirk explains that this can happen when Weld Crete is applied too thick or full strength on a painted surface, preventing moisture from being absorbed and causing the surface to dry unevenly. He highlights this as a common issue when the bonding agent is not properly diluted.

💡Bonding agent

A bonding agent, like Weld Crete, is a chemical substance that helps different construction materials adhere to one another. In the video, Kirk discusses the use of various bonding agents to ensure stucco or concrete sticks to surfaces, especially when dealing with painted or sealed areas. Proper use is critical to prevent issues like peeling or cracking.

💡Stucco

Stucco is a material made from aggregates, a binder, and water, often used for coating walls and other surfaces. Kirk's video focuses on stucco application techniques, particularly the use of bonding agents to ensure a strong finish. He explains how different surfaces, like cementitious boards or sheetrock, respond to stucco and the importance of proper preparation.

💡Cementitious board

Cementitious board is a building material often used as a substrate for stucco or tile. It is known for its moisture resistance and durability. In the video, Kirk demonstrates how he applies Weld Crete to this type of board before adding a stucco color coat, highlighting its ability to absorb bonding agents effectively compared to other surfaces like painted walls.

💡Sealed surface

A sealed surface refers to a surface that has been coated with a protective layer, such as paint, making it less porous. In the video, Kirk discusses how applying stucco to sealed surfaces can be challenging without a proper bonding agent like Weld Crete. He emphasizes the need to dilute Weld Crete in such cases to ensure that the stucco color coat adheres without spider cracking.

💡Adhesion

Adhesion is the process by which one material sticks to another. In construction, proper adhesion is critical for the longevity of materials like stucco. Kirk explains how bonding agents like Weld Crete are used to improve adhesion, especially when applying thin layers of stucco over surfaces like painted walls or cementitious boards. He stresses the importance of following proper procedures to ensure that the materials bond effectively.

💡Pressure washing

Pressure washing is the process of cleaning a surface with high-pressure water to remove dirt, debris, and contaminants. Kirk mentions pressure washing as an essential step before applying bonding agents or stucco to ensure that no dust or dirt interferes with adhesion. He emphasizes that no bonding agent or stucco will adhere properly to a dirty or mossy surface.

Highlights

Kirk Giordano discusses the use of Weld Crete for adhering color coats in stucco applications.

Kirk mentions that Weld Crete should not be diluted, as stated on the can, but explains why contractors sometimes dilute it when applying over sealed or painted surfaces.

Weld Crete is engineered primarily for bonding concrete to concrete, requiring full strength, but contractors often dilute it for color coats.

A color coat in stucco is typically about 1/8 inch thick, and diluting Weld Crete helps avoid issues like spider checking on painted surfaces.

Kirk explains the danger of over-applying Weld Crete full strength on painted surfaces, as it may prevent proper drying and cause cracks.

He emphasizes that proper application methods, including cleaning the surface and adjusting the Weld Crete mixture, are key to avoiding failures.

Kirk describes a story of a client who applied Weld Crete too thickly, which caused problems with the stucco's adhesion.

He advises against homeowners attempting DIY stucco work, emphasizing the importance of following manufacturer instructions or hiring professionals.

A common mistake Kirk encounters is contractors or homeowners adding bonding agents like Weld Crete directly into stucco mixes, which leads to failures.

Kirk highlights that adding bonding agents into a cement mixer dilutes them and causes the stucco to peel off in sheets over time.

He stresses the importance of using bonding agents correctly to avoid costly rework and ensure long-lasting results.

Kirk describes a maintenance-free finish, which involves applying bonding agents and a finish coat that can last for decades without the need for repainting.

He notes that improper use of bonding agents and stucco can result in spider checking due to trapped moisture.

Kirk explains how different types of substrates, like sheetrock and cementitious board, affect stucco adhesion and drying times.

The video concludes with a demonstration of applying stucco color coat over different surfaces using diluted Weld Crete and a discussion on how to avoid common mistakes in stucco applications.

Transcripts

Hello guys Kirk and Jay here, with Kirk Giordano  plastering,

Today what I want to do is I want to talk a little bit about Weld Crete, why, because  I've done a couple videos way in the past when was  

in 2011 and somebody commented about my use of  Weld Crete, first of all, let me explain a  

little bit of background now I've been in the  trade since the late 70s in early 80s I was  

Union and everywhere where we used Weld-Crete  for adhering color coats, we diluted it a little bit.

On the cans, it says do not dilute, and that is  because Weld Crete is actually engineered for going over sealed or painted surfaces.

You put about a half-inch of stucco on that it has a lot of other uses, like mainly, concrete to concrete  and you always go full strength when you do that  

also, keep in mind I'm going to show you a color  coat, a color coat is an eighth of an inch thick.  

Now if you're doing an eighth of an inch thick  of color coat, and you have what I've done here  

I got a piece of sheetrock and then I  got a piece of this, wonder board or the cementitious board.

I'm not certain what kind it is.  I sealed it, that is I painted it with a bonding agent to prove a point.

I'm going to show you something that I tell folks about the color coats.  When I use a Weld Crete, I'll dilute it a little bit sometimes, I'll go half and a half sometimes,  two parts of Weld-Crete to one part water. I use my own judgment. Now guys,

This is what I do you. If you watch what I do, follow whatever it says on the can.

So you don't say well, Kirk, told me to do this or  that.

I'm showing you what we've been doing for 35 years in the trade, every contractor I work for, as stucco contractors, I know about 15.

They do something similar, if not exact, but again I'll tell you the difference between these later, I also like this quikrete they wrote the book on  stucco materials, they sell every stucco known to man.  

This one here is Sika products. It's these two. This one is really not for what I'm intended, but people ask me about it, it's more for a slurry or an additive.  

Say you mix some stucco in it and you put this  in it seals and it makes it more adhesive, It's designed mainly for making tile grout stick better you add it instead of water. 

Getting back on this one here this one is great, it's very similar to this, Weld Crete,  

that we have been using it for over 30 years.

Why because you can put this on and within an hour you can apply your cement or your stucco or your  color coat, and it lasts for about 10 days prior to its use. 

This bonding agent will adhere, so what I'm going to do, guys, I'm  going to start with a little bit of diluted Weld-Crete.

Now okay we're going to do this bottom piece here  now this is over a sealed surface, now that's what  

I like to see it's a light blue, guys  I'm putting it over the sealed surface

I'm putting it over the cementitious board.

I'm also going to do the piece of sheetrock here that I painted with the bonding agent, Okay there's that  that's a can,

I just opened and added some water just to prove a point.

Now, this is a new can of Weld Create, so it's a little darker blue now something to remember, I get some of this moisture out of here, and mix this up a little bit more. 

The more you mix it turns the darker blue.  Something to keep in mind guy as far as applying a  

stucco color coat onto a painted surface there's a reason why if we put it too blue and the house is painted very well why it'll spider check it has something to do with Weld Crete, it must be diluted for this purpose.

It has to do with us, what I'll get into in a second which is well dry in time, Okay this is heavier than this now if you take a house that's is 100 years old it  already has 20 coats of paint on and some of those  

coats are extremely quality paints.

Now you paint full strength, Weld-Crete on it, and keep in mind.

I'm referring to a color coat 1/8 of an inch thick, 1/8 of an inch thick. Everything on that can is for 1/2 inch or more like concrete to concrete.

They don't mention color coats.  However, this is well known in the plastering industry what I'm about to show you.

Okay now this is heavy, this is diluted these two  are diluted, and again this is the sheetrock and this is just cementitious board.

I tell folks this is what I do, and I was hired by a fella in Tiburon, he was a fireman, he said gee, Kirk, can I  save some cash and do something?

The average stucco color coat about starts around 10 grand and that includes pressure washing the house, then applying the bonding agent. 

Then color coating the home, stucco color coats adhere to the bonding agents they won't adhere to a painted surface and while I'm talking about adhering nothing adheres to dust, dirt or a mossie surface.

Nothing.

None of these products here will stick to a dusty surface.

Folks so it's got to be clean, anyway getting back to the firemen in Tiburon, I said okay man, get yourself a gallon or get two gallons of this Weld-Crete to throw 1/2 gallon of water in each can and apply it lightly to the house.

And I'll credit you back the cost for what it would take us to do that. Then when I came to the house it was dark blue, what does that mean?

It looked like this can, and I looked at it, I thought dude what's that about? I told you two gallons and one gallon to dilute the Weld Crete. 

He says, well I want to make sure it adheres.

I said, man, you put it on so thick that if we applied a half-inch or an inch. It would adhere, but  now you over-sealed it because you applied too many coats or applied it full strength.

You overpainted it on, thus if I apply  a stucco color coat, an eighth of an inch it will spider crack. 

the wall no longer has the absorption then it'll dry by the outside air and when the outside air dries it and  

which will take a long time. It'll spider crack or spider check, if we now apply the stucco color coat.

I tell people to let me do the bonding agent and I also had it the other way too I worked for a fella for  

many years and he said, Kirk, what can I do to  help, and I thought, dang, there's that question  

again. I said alright man, have your guys apply it and I explained to him how they should do it.

I got there with my crew and I couldn't see it.

I thought I told you to apply the Weld-Crete, he says we did, and I thought man If I can't see it, then I've got to apply another coat because I can't risk the stucco color finish coming off.

And having you conveniently forget that I told your guys to apply it. Anyway, to make a long story short I don't allow it anymore, If folks say gee what can I do to help?  I say stand back watch just do it, that's all the  

the help we need, so what I'm going to do guys is, I  got to let these set when this one dries it's  

going to be dark blue this these took in the dark  blue, this is what I actually want and  

guys, I've rolled this stuff on. I've shot it  on with airless, I've used brushes a lot of ways  

to do it.

We'll get into that well what I'm going to do is I'm going to let these set I figure in an hour, it's going to be a pretty hot day. I mean  yesterday it was 100 degrees, it's about noon it's  

cloudy so as soon as the sun comes up it's going  to dry this out, when we get to that next stage, I'm going to put some color coat on it and  then we're going to do that exact same thing where we wait on it, while I'm getting this in  my head, let me tell you another story.

These products and there are about 10 bonding products if you guys go to various parts of the country or various hardware stores, where they say you can add this in the material.

What they are referring to is, if you mix a little slurry and you put the coat on the wall, you can do it that way.

I've had many people say, Kirk, I'm going to put a gallon in my cement mixer and eight, 100-pound bags, I tell them all it will fail off within six months of being applied! The stucco finish is going to come off your house in sheets!

Have I seen that happen?

About 20 times, so don't put bonding agents in the material unless you're doing a slurry and you're going to just put a little patch and fix something, but on a whole house on a color coat eight bags, it will dilute any of these products to uselessness, of course, you couldn't put blue in a colored mix of stucco anyway.  Nor add the white, Quikret in the stucco mix!

I've actually had a few guys call or write me and say  you're right and the company's wrong, I said well  

no the company's right.

if they say something, but the method you're talking about is not for a stucco color coat, we are talking about a color coat on a house.  Now we do a lot of maintenance-free finishes that  

means, instead of painting the house, we pressure wash put a bonding agent on the walls, then we apply a maintenance-free finish coat.

An eighth of an inch thick, when I mention a  maintenance-free finish, which means it lasts forever.

It doesn't come off, the colors start to fade in 30 to 60 years, but it continues to hides all bad finishes and things of that nature anyhow I'm going to go ahead and let this set because I got a lot of other things we're  

doing.

we'll come right back to this and apply this finish. We are at the stage that these are drying it's been a good hour or longer.

I put a little bit of color in this color coat just to so you could possibly see it better.

Now what I'm doing is I'm using the material, which is called La Habra finish coats.

It is is a color coat guys and its sand grit is 20/30. Not smooth and it's not heavy so this is the medium sand grit, that's all I need to do right there, I'm going to point out guys if, 

you're ever considering this, I'm just going  to put this right here because I can use this is over  

sheetrock which has a lot of suction, this has  a whole lot of suction these won't spider check.  

Because it's designed for that again all of these  bonding agents, you use them others according to  

what their description says on their cans or bottles.

They will not fail, the reason we get spider checking is again, because of the moisture being trapped it can't suck in, if the stucco can't suck in it has to dry from the outside  

therefore it'll spider crack. Plus the bonding agent was applied full stretch which caused further spider checking. Well, we're done with this demonstration.

Jay is going to take his handy-dandy camera there and zoom in now.

This I'm just going to do on all of them like a sand finish, why sand finish?

Because if I do a sand finish it'll dry out a lot  faster than say the trowel finish, because the sand is able to breathe, I'm taking the outside air, I'll  hit this just for the heck of it and here and  

I'll show this to you see how fast that sucked up  because this is over the cementitious board.

If this is dry already, that because it's dry because it's  the moisture has already been sucked out onto this board.  

If I was on a house I'd hose it down and hydrate  it, then have the stucco finish hydrate together as one.  

This is still wet because it's on sheetrock, these  are going to stay wet, this one's going to stay  

wet for quite a while because this is painted on full strength, this is diluted so  

we'll come back when the time comes to see what it looks like. I want to express once more that  

these bonding agents, if you're applying a stucco color coat do not put them into a mixer just my tip to you! 

Guys if you do add it to the mix, it'll come off in sheets, I had bid a house for a color re-surface, it was on a river and I thought what a

cool place to work, we can view the water and have fun applying, like on a beach. I bid their stucco re-finish at 7,000 dollars, they called me back a couple weeks later and said, Kirk, we got another bid of 6,500 dollars? I said okay, cool,  

you were too far for me any way you're two hours  from my house, I bid it that low to be on  

the river anyway.

Six months later, she called me back and says the new color finish was peeling off in sheets!

I explained, either they applied the bonding agent over a dirty surface or they put the bonding  agent in the mixer, you cannot do either.

This poor woman says, the other plastering contractor did add it to the mixed color coat cement and they showed it to me, it says on the can, it can be added to the mix. Well, that means something different.

It doesn't mean put a gallon of this or even  ten gallons in a mixer with 800 pounds of stucco circulating or mixing, then try to put on an eighth of an inch thick on a wall and expect it to adhere?

Don't do it guys anyway let's see what this does. Jayson and I got a bunch of other crap we got to  do and we'll come back to this and take a look at it.

All right guys were back, let me conclude this test. There's, what we started off with. So dark that is wet, FYI, cementitious finishes always dry lighter, this one is permanent it didn't  

need a bonding agent it sucked into this cementitious background, this one will come off because  

it doesn't have a bonding agent. This one here is permanent, and so are these. They are all permanent here because they have the bonding agent now. Yeah, even though it's over a cementitious board it  

was painted plus the Weld Create.

Wow, this looks like the Amazon River if you go close, it really looks like the Amazon.

Jason, can you zoom in on this one that looks like the Amazon River would I come up with that my girl just walked in the backyard she says, oh those look cool those look indeed, like the Amazon River.

Now that's not what people want, though anyway. To get back on this, the weld crete is easily one of  the strongest liquid bonding agents I've ever  

encountered I know at least 20 licensed plastering fellas, guys who all have  30 years and they say the same thing it's one  

of the strongest bonding products.

The thing is I thought was there's a chemical reaction also because it's so incredibly strong this bonding agent it's made to hold an inch of stucco to a half-inch on a house. 

or a vertical wall it can do it, so between the  air coming on the outside and drying it out and  

between the chemical composition of it, you know, ole Kirk, is an applicator guy I don't know much about electricity but I know I can flick a switch and make the lights come on or tune them off. 

I don't know much about the engineering of this  resin-based type of bonding agent but I'm sure  

some of you guys do.

Do any of you folks have opinions?  of why this is so incredibly strong let me know.

Lastly, I'll just say that if I was Larson's the makers of Wel Crete, I would not put in the description as far as color coats go. Why, because if I tell somebody this  

is what I do.

Anyway, don't do what ole Kirk does because I don't want anybody to call me and say, gee, I tried your method it didn't work that's not what this is about if Larson's can be diluted guess what people would do? They would dilute it to nothing, or they  wouldn't know how to bond the rest of the wall.

So you look at a wall, not wall sealed they wouldn't  be able to determine how many coats the paint does  

that has on it, to determine the right amount of  Weld Crete, so that's something that's kind of off  

limits for Weld Crete, and it's off-limits with me too. But because somebody said I  

was trying to save money by diluting it I thought  don't be crazy you don't save any money if you got  

to go back and redo a wall that's like putting a five to one sand ratio with cement. If we use five times the amount of sand to save money. of cement. You don't save any money if that wall falls down. That would cost anyone a fortune to repair it again. So I do not dilute this to save money I dilute it because I know what I'm doing and every job is different so you guys  do what's on the label and most of you homeowners  

and you do it yourself guys call a licensed plastering contractor if you're going to do a color coat because that's  

just the tip of the iceberg on stucco color coat applications. There are so many different things that could  

blow a job so anyway guys my name is Kirk I'm with  Kirk Giordana plastering, and my lovely girlfriend she's out  

here all the time, this is her garden, that I'm  messing up, this is and you didn't even mention  

that you spelled weld Crete

Anyway, my name is Kirk Giordano with Jason on the  the camera we thank you for watching and as usual.  

We'll see you on the next one.

Once again folks we thank you for watching,

and I really enjoy all your comments

if you guys like this video, please click  the like button down below and also if you enjoy what we do subscribe to our channel.

so we can keep making these videos for you.

My name is Kirk and Jason we thank you for watching and from the  entire Giordano family we'll see on the next one.