What are those horizontal cracks in my basement floor?

- Wednesday, November 24, 2021

Some cracks are pretty easy to identify due to their meandering, spidering appearance.  But straight, horizontal cracks are something else entirely.  In this episode, Adam, talks about these manmade horizontal cracks, or expansion joints, and how and when to fix them.

Narrator: It’s time once again for the “Crack Man Podcast” hosted by A1 Foundation Crack Repair. I’m Darren Kincaid here with the Crack Daddy himself, Adam Tracy. Adam and The Crack Man Rich have over 30 years’ experience in the construction industry. Rich as over 25 years as the president and founder of A1 Foundation Crack Repair. This podcast provides expert basement waterproofing, concrete repair, and preventative maintenance tips for homeowners and businesses. A1 Foundation’s valuable insight will help avert a disastrous flood within the basement, health problems associated with water infiltration, and protect your biggest investment….your home. The topic of today’s podcast: What are those horizontal cracks in my basement floor?

Narrator: So, Adam, some cracks are pretty easy to identify, but I have a feeling these horizontal cracks might be something else altogether. Do you get any calls on these types of cracks?

Adam: We do get calls on these, and in fact we had one just the other day. It was a nice couple who was buying their first home in Westwood in Massachusetts. It was a newer home, and they had a pretty large footprint in this particular house. The basement was completely unfinished so they got to go down there as part of their initial walk-through. And the realtor calls us up with the potential buyers on the phone and they had lots of concerns and questions.

So, they called us up and they said, we’re seeing all of these really large and deep cracks everywhere in the basement, they’re straight lines going from one end to the other. And I paused for a second and tried to understand, kind of the situation that they were in, imagining some potential solutions and issues that they had there. The first question I asked is are they zigzagging cracks on the floor or are they perfectly straight lines that go from end to end. And after a little bit of looking around and a little bit more investigation on those particular cracks that they saw, they realized that they were very straight lines. They weren’t exactly zigzagging cracks like the typical crack that you would see in the floor.

So, at that point I asked them just to send a photo over so I can just confirm with what I thought it was, and before they did confirm that they weren’t actually cracks, they were expansion or control joints in the concrete floor. So they didn’t know what that was, which is very common because you don’t always see them in residential construction, although in newer homes it’s pretty typical.

What a control joint or an expansion joint is, is a cut in the floor, or what they do is they put a board in there to make it when they pour, and it may go down a quarter of the depth of the concrete. And it’s an area that will allow the floor to crack naturally in a known spot as the temperature and humidity and the shrinkage of the concrete all comes together shortly after construction.

So, the first indication that it’s not necessarily a crack is that it’s perfectly straight. These are cuts that they’ll do with a saw after the concrete has cured, or they’ll use materials embedded into the concrete, which are perfectly straight, as they pour the concrete. So why did they put these in here? The reason why they’re there, it’s the same reason why you see them on concrete sidewalks, you’ll see them every few feet down the line. It’s an area that they know where the concrete will expand and contract, and an area where they know it can prepare for an actual crack in the concrete.

So, in most of these homes, especially with a larger home, you’ll see a much larger slab of concrete than necessarily a 1950s ranch, right? If you’re going with the 3,000 sq. ft. colonial, that concrete’s much larger in area than an older ranch, and when you have a much larger area, it’s subject to more cracking because it’s more shrinkage across the entire surface. So a lot of builders, we will cut these lines in, so that way, it cracks exactly where they can expect and they won’t see cracks everywhere. So, what do you do with this? Well, most builders in most construction will leave them as is and just walk away, and it’s just a line on the floor. The problem is, is that usually, it will crack down into that seam that they create.

So it’s really no different than a foundation crack on the floor, it’s more of just we know where it’s going to be, it’s not going to be very widespread. So things like insects, wood-destroying insects like termites and wood boring beetles can come up through there. You get that organic breakdown smell that can come up through the floor as well, you can get moisture that comes up through these cracks in the expansion joints. So these are generally okay in terms of what they are, but what we want to do is we want to make sure they’re properly sealed. And sealing an expansion joint is very similar to a crack, except, we want to make sure that the material that’s being used is flexible, because that flexible material will allow it to actually move with the concrete, which is what it’s design is.

So, if you put a hydroxy cement in there, or a rigid material, you’ll just see that it will pop out over time. So, the right material in there is a flexible material, it seals it up, it keeps the bugs and moisture and insects and smells away, and then you’d preserve the value of the house and the slab of concrete, so it doesn’t actually crack everywhere. So they had many concerns, after a few minutes of conversation, after the photos, we were able to explain what it is, give them an idea on what it’ll be to seal those up properly, so that way they can build out their future basement renovation, which is what their plan was. So it was a lot of panic in the beginning, and then a lot of nice calmness in the end. So, it was a nice conversation with this couple.

Narrator: Very good, Adam. Thanks for explaining the importance of expansion joints and how and when to fix them.

Narrator: If you have a basement water problem and think you need a professional, or, if you’d like more information on foundation crack repair and basement waterproofing topics, please visit A1FoundationCrackRepair.com or call Rich at (866) 929-3171. Or you can email Rich at info@a1foundationcrackrepair.com. Thanks for listening and keep that basement dry.

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A-1 Foundation Crack Repair, Inc. is a fully registered home improvement contractor. Contact us today to talk to a knowledgeable, master waterproofing professional.

E-mail: info@a1foundationcrackrepair.com
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Call Us Today at 866-929-3171

A-1 Foundation Crack Repair, Inc. is a fully registered home improvement contractor. Contact us today to talk to a knowledgeable, master waterproofing professional.