tolerances for floors/walls

I would imagine that this comes up in both new and existing construction, but what building code reference material would one utilize concerning acceptable measures of levelness in floors and plumbness in walls?

For example, I was contacted by someone in the construction field today who wanted to know what was acceptable regarding floors and where that reference could be found. How much fraction of an inch off per foot, etc. The floor in question was framed with manufactured I-joists. The difference in height over an 18’ span was reported as 1.5".

Any input would be appreciated.


In Arizona using the UBC as a standard (with local changes).

Floors–1/2" in 12’ or 3/16" in 4’

Wall Corners–Perpendicular within 1/4" in 10’

Wall Construction Flat–or no more than 3/8" in 8’ (bulge)

But none of the contractors abide by the framing codes, nor do the city officials.

Unless something is so out of whack shimming in back of the sheetrock won’t suffice it’s OK here.

Are you saying the house is out of level by 1 1/2" ? Don’t sound right to me, not acceptable.

As to a standard, there must me one somewhere that states My house will be constructed plumb and level to tolerances of 1/4" +/-.

Marcel :slight_smile: :slight_smile:

My house is not only plumb its better then plumb.
Roy sr

Hi. Roy;

How can it be better than plumb?? Did you buy a new laser level?? ha. ha.
Some guys on my job can mess that up too!!

Marcel :slight_smile: :slight_smile: :smiley:

This came from My brother 40 years ago and I liked it so saved it to use .
The guy asked is it plumb and brother said Plumb why shes better then plumb and every body lost it.
Humour from the past .
It improves the day.
Another I rarely use but had my client last week crying .
Thats Ungood ,
We were talking about a section of floor that needed changing from dogs P
After he was able to talk he turned to the agent and said I like this guy he is the greatest.
You have to know you client before you do these things .
Roy sr

Now that you mention it, I faintly remember that same saying.

Thanks Roy for the Mental block refresher.

Marcel :slight_smile: :slight_smile: :wink:

Buy the “Residential Construction Performance Guidelines” from the NHBA Bookstore, most of the code related book sites or ITA. About 100 pages spiral bound and gives building tolerances for professional builders and remodelers, and the recommended repair for the issue.

Good reference book. We use it for construction monitorings & expert witness in addition to mfg installation guides, codes, etc.

Is this it Dan?

Flatness/Levelness; Finished concrete surfaces of slabs on grade and wood floors should neet the following minimum tolerances for flatness F(F) and Levelness F(L) in areas with finish flooring materials.

ASTM E 1155/E 1155M for a randomly trafficked floor surface, except meet or exceed finish flooring manufacturer’s required substrate tolerances where they are more stringent than the following:

Linoleum flooring and Cork flooring:
Flatness, F(F):35
Levelness F(F)20

These are just examples.

Similar levels would be appropriate for walls.

Marcel :slight_smile: :slight_smile: :slight_smile:

The first place to look is in the locally adopted construction codes (and the reference standards like AWC, ACI and AISC documents), and if ya strike out there or you really don’t need a mandatory standard then ya go to industry references like the NAHB Guidelines.


Now we sure are all confused. :slight_smile: :slight_smile: :wink:


Brian - You got it!!

If the floor is out of level 1 1/2" in 18’ the whole building is racked. Absolutly unacceptable. If the carpenter can’t read a level he shouldn’t be a carpenter. With the lazer levels available today there should be no deviation from level and plumb. We did it with a water level for years and our structures were never out of level. But then again a water level doesn’t lie.

What planet are you guys writing from? I have never seen a code inspector carrying a level. Never seen one even try to eyeball level and plumb. Seldom will one find a plumb and level house (new or old). The builder tries (hopefully) but with changes in moisture level, settling and a myriad of other factors working on the structure, things don’t stay plumb and level. Having said all this, 1 1/2 inches in 18 feet is a bit much!

Yes, I agree that 1-1/2" out of level is way too much and unacceptable.

1/4" in ten feet is still too much but a lot more understanding.

Plumb is Plumb and level is level. That is what I paid for and that is what I want.
Too. much to ask for a buyer, not when you are paying for it.

Imagine allowing 1/2" out of plumb on a multi-story building. Naa’ would not work to well. Imagine a slab out of level for multiple condo units that is out of level 1-1/2’ every 18’ Naa’ not quite acceptable.

Residential, standard might let you get away with 1/4" in ten vertical or horizontal.

Any worse than this, Do It Again Sam. Sorry, but I do not need a book on this one.

Marcel :slight_smile:

While most HI’s would agree that something out of level 1-1/2" in 18’ is too much, there are still two problems …

(1) How do you justify flagging that as a defect, as there are substantial costs involved in repairing that? If nothing can be referenced then there is a better chance of being dragged into a lawsuit over the issue (where you lose as soon as legal action is started, whether you are technically correct or not in the end).

(2) Where do you draw the line on what is a defect and what is not a defect. And what tolerance should be applied in generally establishing the scope of a repair, which has an impact on deciding how serious that defect is (1/4" in 10’, 1/2" in 10’ or 1" in 10’)?

Dan and I have agreed in the past that a fairly common and pretty reasonable upper limit for a home inspector to use as a guide is … Distance/240 (or 1" in 20’). That is based in part on the visual deflection limit of Span/240 for structural members in most model codes and reference standards (comfort limits where sagging can be felt are more restrictive, generally at Span/360).

That is still not a legal or code requirement, which may or may not be more restrictive depending on local code requirements and the type of member.

JMO & 2-nickels … :wink:

The NAHB “Residential Construction Perfromance Guidelines” publications (which many builders will accept at face value as a legitimate source) say:

“The interior face of wood-framed walls shall not be more than 3/8 inch out of plumb for any 32 inches in vertical measurement.”

“Walls shall not bow more than 1/2 inch out of line within any 32 inch horizontal measurement or 1/2 inch out of line within any 8 foot vertical measurement”

It is a VERY useful book…

If a builder working for me allowed a tolerance of 1 1/8" in 8’ I would fire his a** in a heart beat.Considering the average 2 story is right around 20’ in height above the foundation that translates to 2 7/8 out of plumb. Absolutely unacceptable.

If they used engineered trusts and there is an one and a half inch difference something is absolutely wrong either framing wise or foundation wall on the low side of the structure. In this case I woud defer to structural engineer.