Floor levelness

Anyone have a code reference for wood framed floor levelness? NAHB says 1/2 inch over 20 feet.

codes are only enforced at time of construction, if you have a 100 year farmhouse with a 2" drop in the center of a 15’ square room, you can call it out but i dont think you could reference a code.

As HI’s it shouldn’t be an issue of codes. Unless you are holding yourself forth as a code inspector. I find if I don’t ever reference a code then when anyone tries to use code as a defense against my opinion my argument that it is not based on code holds a lot more water.

Levelness is a subjective matter. It could be a defect depending on severity and age of the structure. A new home where you need repelling gear to cross the living room is pretty clearly a defect. Same home out 1/2 inch in 20 ft probably not unless it creates obvious situations or problems. Same thing for an old house but more leeway for slope seems reasonable.

Some engineering guidelines allow for one inch in 20 feet. Buyers should understand that older homes settle over time. We cannot be a predictor of past or future conditions. Call it out, suggest refer, and let buyer decide.

2006 IRC section and table R301.7 says deflection max is L/360 or (20x12)/360 = .67" for a 20’ span.

Michael, is that for new construction?

It’s the IRC…it applies to any construction, new or existing, where that code has been adopted.

Thank you Michael. Also for not assuming I needed the information to write up a home inspection.

Does the code allow for proportions? Could it also read as .335" for a 10’ span and so on?

Here’s some snippets from the 2006 IRC. You can decipher it but, as far as I know, the answer to your question is yes.

Deflection.pdf (101 KB)

Deflection and floor leveling are two different animals; deflection is simply the amount of deviation from a straight line when FORCE is applied…there is no code that I am aware of that states floors have to be level and walls have to be plumb… matter of fact it was pointed out to me by the head of our local building department when I inspected a fast track home whose interior gable wall was out of plumb by 1 1/2 inches. I poured through the ICC code book and couldn’t prove him wrong. My client was pissed at the builder and the building inspectors however he had no recourse as they both said it was within industry standards.

Jeffrey…I understand and agree with your statement above, at least about deflection being different from leveling. For lack of any better direction I have used the deflection criteria before when critiquing out of level floors. Perhaps that is not an accurate thing to do.

Here in Triad of the Carolina’s the soil is so unpredictable, as a result its common to have uneven floors, especially with older homes. Unless its something out of the ordinary, I simply point out to my clients that unlevel floors can and often occur over time given the soil upon which the house was built and furthermore that they should expect that doors may need adjusting from binding and at times cracks in drywall / plaster may come and as the weather changes and / or change in the moisture content of the ground.

Because of the droughts we had here in the Carolinas for awhile followed by periods of excessive rain, I have been fortunate enough to make quite a bit of money in leveling floors the last few years…my experience shows that its often isolated to the interior piers of which many simply did not have a proper footing for the interior loads coming down on same. It can be very difficult and at times expensive to fix same. My price to go inside a crawlspace (usually a tight one at that) and attempt to jack up girders and pour additional footings runs between $2500 - $5000.00.
As you can see that can be pretty expensive and often its unnecessary unless it becomes a structural issue or a client is looking at putting in tile or slate flooring which means you have to have a stable floor system.

Most people know what they are getting however I am quick to educate first time buyers (or those new to the area) more than those who have purchased and sold multiple homes.

There is nothing wrong with exceeding the code when it comes to safety issues however the inspection industry gets a black eye when they start making recommendation for items which are outside their SOP’s and safety guidelines.
If an inspector is making recommendations for a builder or seller to spend $2500 - $5000 or more in repairs… they better be necessary.

anyway that my 2 cents… oopps…I see the time is getting close to my daily hot fudge sundae… time to go…

warm regards


OK, just to be clear (I’m not sure if that is an admonishment of my previous post or inspectors in general) but when I said I used the deflection criteria when critiquing a floor levelness I meant in my mind to determine whether I should defer to a structural engineer or not. I would not and do not make any recommendations for a specific repair in such a case, that would be left to the SE. Enjoy that sundae :smiley:

I wonder where the NAHB gets it’s standard of 1/2 inch over 20 feet from? Thin air?

Post Tensions Slabs are initially pretty level, and over time for the most part stay that way.