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Acceptable grade of basement floor

L

layman25

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Joined
Mar 9, 2025
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7
Location
Ohio
Hello all, I am a layman seeking guidance. I hired a contractor to add a bathroom to an unfinished basement with a concrete floor. He used self-leveling concrete. After the bathroom was completed, I became concerned that the floor was not completely level because of some clues. I purchased an electronic level and angle gauge. The readings are all over the place between 0.0°-1.5° depending on where the meter is placed. Around the shower, it is 1.4°.

Is there an tolerance for slopes like this, or are those numbers unacceptable? I am in Ohio if it matters. Thanks.
 
1 percent is roughly 1/8" per foot. For handicapped accessible parking spaces and sidewalks, a 2 percent cross slope (approximately 1/4" per foot) is considered to be "level." For concrete floors, a traditional standard was a deviation of not more than 1/4 inch in ten feet. But that doesn't mean that the floor would be perfectly flat, with a slope of 0.2 percent. It means that within that ten foot length no point on the floor should be lower than 1/4-inch below the highest point.

The International Residential Code doesn't prescribe a tolerance for flatness of slabs on grade. That's usually up to whoever writes the specifications.
 
layman25 said:
Hello all, I am a layman seeking guidance. I hired a contractor to add a bathroom to an unfinished basement with a concrete floor. He used self-leveling concrete. After the bathroom was completed, I became concerned that the floor was not completely level because of some clues. I purchased an electronic level and angle gauge. The readings are all over the place between 0.0°-1.5° depending on where the meter is placed. Around the shower, it is 1.4°.

Is there an tolerance for slopes like this, or are those numbers unacceptable? I am in Ohio if it matters. Thanks.
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Did you have him secure a permit and get inspections?
 
"Okay you got me with that one." Said the voice.

How about the floor drain in a men's bathroom or a commercial kitchen. It takes a talented finisher to get those done correctly.

Now what about that permit?
 
jar546 said:
Did you have him secure a permit and get inspections?
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Yes, definitely.

jar546 said:
Water has to go to the drain in the shower just like a garage slab has to drain towards the door at an angle.
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I'm not referring to the shower pan itself - the laminate flooring near the shower is not level. I first noticed because there is a spot in the shower where there is some give because there seems to be a gap between the pan and the floor.
 
So he used self levelling concrete on top of an existing basement floor to prep it for the laminate floor? First problem is … self leveling concrete … isn’t self leveling.
 
layman25 said:
Hello all, I am a layman seeking guidance. I hired a contractor to add a bathroom to an unfinished basement with a concrete floor. He used self-leveling concrete. After the bathroom was completed, I became concerned that the floor was not completely level because of some clues. I purchased an electronic level and angle gauge. The readings are all over the place between 0.0°-1.5° depending on where the meter is placed. Around the shower, it is 1.4°.

Is there an tolerance for slopes like this, or are those numbers unacceptable? I am in Ohio if it matters. Thanks.
Click to expand...

Is your level .... level?
 
e hilton said:
So he used self levelling concrete on top of an existing basement floor to prep it for the laminate floor? First problem is … self leveling concrete … isn’t self leveling.
Click to expand...

The basement floor was unfinished concrete which was sloped. He used self-leveling concrete and then laid the laminate floor atop it.

Inspector Gadget said:
Is your level .... level?
Click to expand...

I used a Klein Tools 935DAGL. Is there another type of device I should be using?
 
Yankee Chronicler said:
The International Residential Code doesn't prescribe a tolerance for flatness of slabs on grade. That's usually up to whoever writes the specifications.
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Here is your answer. And, since you said you had all of the work done with a permit, any issues would have been flagged and required to be fixed. Self-leveling should do exactly what its name is. There will, however, always be imperfections as there are other considerations such as how to match up with a door threshold or intersection that is not level, etc. So I don't know, without any pictures to go by, whether this is legit or you are a nitpicky customer looking for a reason not to pay and someone here will tell you what you want to hear. Again, I don't know. What I do know is that this is not a code issue; it is a civil issue.
 
jar546 said:
Self-leveling should do exactly what its name is.
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Sort of. It’s like thin pancake batter, the overall surface is smooth and level if poured properly. But the edges won’t self-feather, they will have a rounded edge. Too many hack contractors think it's a miracle product for getting a perfect floor, when actually it takes a little skill.
 
The professional flooring people I've seen use "self-leveling" concrete use some hand tools to feather it into the corners and edges. More importantly, they also use a big floor sander to take out the imperfections.
 
Yankee Chronicler said:
1 percent is roughly 1/8" per foot. For handicapped accessible parking spaces and sidewalks, a 2 percent cross slope (approximately 1/4" per foot) is considered to be "level." For concrete floors, a traditional standard was a deviation of not more than 1/4 inch in ten feet. But that doesn't mean that the floor would be perfectly flat, with a slope of 0.2 percent. It means that within that ten foot length no point on the floor should be lower than 1/4-inch below the highest point.

The International Residential Code doesn't prescribe a tolerance for flatness of slabs on grade. That's usually up to whoever writes the specifications.
Click to expand...
careful, I believe the post used 1 degree Not 1 percent Just looked it up and Sin of 1 deg is 0.017 x 12 inches so 0.204 inches or 3/16" / ft A little less than your 1/4 " but I agree, the perception would be level an that slight diff would or should be imperceptible so would one percent be .01 x 96/ 8ths or or 9.6/ 8ths or 1 1/4 " per ft it is after 9 PM and my brain is a little fuzzy
 
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jar546 said:
Here is your answer. And, since you said you had all of the work done with a permit, any issues would have been flagged and required to be fixed. Self-leveling should do exactly what its name is. There will, however, always be imperfections as there are other considerations such as how to match up with a door threshold or intersection that is not level, etc. So I don't know, without any pictures to go by, whether this is legit or you are a nitpicky customer looking for a reason not to pay and someone here will tell you what you want to hear. Again, I don't know. What I do know is that this is not a code issue; it is a civil issue.
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The contractor has been paid in full. But he broke numerous parts of the contract. I'm trying to figure out if this is a real issue or normal.
 
There are no specific criteria in the Residential Code for either levelness nor flatness of concrete floor slabs. As I indicated in a previous post, any expectations in this regard are generally either shown on the construction drawings or written into a written specification. Either way, the criteria would be part of the contract documents, not a code requirement.

As Jar46 wrote in post #12, "What I do know is that this is not a code issue; it is a civil issue."
 
Genduct said:
careful, I believe the post used 1 degree Not 1 percent Just looked it up and Sin of 1 deg is 0.017 x 12 inches so 0.204 inches or 3/16" / ft A little less than your 1/4 " but I agree, the perception would be level an that slight diff would or should be imperceptible so would one percent be .01 x 96/ 8ths or or 9.6/ 8ths or 1 1/4 " per ft it is after 9 PM and my brain is a little fuzzy
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Yes, it was in degrees.

Inspector Gadget said:
I'm assuming that's a laser level?
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No, it's a digital angle gauge. I ordered a laser level and will upload some photos.
 
Yankee Chronicler said:
There are no specific criteria in the Residential Code for either levelness nor flatness of concrete floor slabs. As I indicated in a previous post, any expectations in this regard are generally either shown on the construction drawings or written into a written specification. Either way, the criteria would be part of the contract documents, not a code requirement.

As Jar46 wrote in post #12, "What I do know is that this is not a code issue; it is a civil issue."
Click to expand...

Thanks. Is there a commonly accepted standard? At some point it has to pose a long-term structural problem but I don't know what that is.
 
layman25 said:
The contractor has been paid in full. But he broke numerous parts of the contract. I'm trying to figure out if this is a real issue or normal.
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Not a real issue at all. I have never met a truly level floor. It will not cause structural issues - or issues with setting cabinets or plumbing fixtures.

If the contractor got it within 1 degree, he's pretty good. Not perfect, but he's hitting the 98% you want to see in that area. That last 2% costs twice as much and takes twice as long...

I advise that you do not try to make an issue out of it, you will hurt your case about the other items in the contract he violated by appearing too picky. It's hard for a homeowner to argue with a contractor because the homeowner will struggle to know the difference between construction defects and standard practice, and once a homeowner clues in to the fact that something was missed, they often muddy the waters with issues that are not really an issue.

Best thing to do is to get someone impartial and knowledgeable to look at it and tell you what is a problem and what is not. You want someone who's pretty laid-back so that they don't drag in a bunch of personal preference about the way they do things vs the way the other guy does things - you want them to identify objective problems, not personal opinions.
 
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What did the plans call for?

Will or did the floor have tile installed, a tile guy can sometimes correct a number of anomalies in a floor.
 
Thanks to everyone for your feedback. I obtained a self-leveling laser level. When I measure from one side to the other, starting where the flooring meets the shower pan, I see the laser striking the tape measure 1 5/8 inch. Where the laser rests on the opposite side, I see 2 inches. The distance is 104 inches.

So that's 0.38 inches across 8.67 feet, which is higher than the 0.25 inches across 10 feet previously cited, although I understand that does not necessarily apply. I do not know if that's the highest point on the floor.

Thoughts?
 
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