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 DoobieG 01-29-2010 03:28 PM

R311.5.2 HEADROOM stairway code in Michigan question

Hi,

The code states:
Quote:
 The min. headroom on all parts of a stairway shall not be less than 6’-8” measured vertically from the sloped plane adjoining the tread nosing or from the floor surface or platform.
OK I am trying to understand what "sloped plane adjoining the tread nosing" means. Can anyone explain it?

The stairway in question is a stairway to a basement on an existing, older home.

Thanks.

 wnabcptrNH 01-29-2010 03:39 PM

Quote:
 Originally Posted by DoobieG (Post 391279) Hi, The code states: OK I am trying to understand what "sloped plane adjoining the tread nosing" means. Can anyone explain it? The stairway in question is a stairway to a basement on an existing, older home. Thanks.
okay as you are walking down the stairs and you have the ceiling running paralell to the stairs right? well at some point there is a turn from that ceiling onto the flat ceiling of the basement. At that point you measure down to the nearest nose of the step below and you must have 6'8"

 cellophane 01-29-2010 03:43 PM

Measure from the nose of your tread up 6'-8" vertically. Do this a couple times and connect the points - that will give you a line that follows the slope of your stair. That line (ceiling slope) can't be lower than 6'-8" AFF (above finish floor) from the nose of the tread or a landing.

Basically that is there so you don't crack your head on a low ceiling and it allows some room to move things like couches up and down a staircase.

http://img27.imageshack.us/img27/348...ement01.th.jpg

 wnabcptrNH 01-29-2010 03:52 PM

Quote:
 Originally Posted by cellophane (Post 391286) Measure from the nose of your tread up 6'-8" vertically. Do this a couple times and connect the points - that will give you a line that follows the slope of your stair. That line (ceiling slope) can't be lower than 6'-8" AFF (above finish floor) from the nose of the tread or a landing. Basically that is there so you don't crack your head on a low ceiling and it allows some room to move things like couches up and down a staircase. http://img27.imageshack.us/img27/348...ement01.th.jpg
yeah what he said but typically its only a problem at the point I stated or at least that was only where I ever ran into it

 DoobieG 01-29-2010 03:56 PM

Quote:
 Originally Posted by wnabcptrNH (Post 391282) okay as you are walking down the stairs and you have the ceiling running paralell to the stairs right?
No actually it's an open stair well, there is no ceiling - it's all open and you can see from the main floor the entire stairway into the basement. The stairs go half way down to the basement, and then there is a landing, and from the landing the stairs double back the rest of the way down and go in the opposite direction of the first set of stairs - not sure what you call that kind of stairway.

I am just trying to figure out how to measure the head clearance of that last step, the last step at the bottom of the stairs projects maybe half way or 2/3 of the way under the the basement ceiling. It's an older home built over 50 years ago.

What is the nose of the step?

 wnabcptrNH 01-29-2010 04:04 PM

Quote:
 Originally Posted by DoobieG (Post 391301) No actually it's an open stair well, there is no ceiling - it's all open and you can see from the main floor the entire stairway into the basement. The stairs go half way down to the basement, and then there is a landing, and from the landing the stairs double back the rest of the way down and go in the opposite direction of the first set of stairs - not sure what you call that kind of stairway. I am just trying to figure out how to measure the head clearance of that last step, the last step at the bottom of the stairs projects maybe half way or 2/3 of the way under the the basement ceiling. It's an older home built over 50 years ago. What is the nose of the step?
the nose of the step is the tip of the step...meaning the overhang of the tread over the riser.

 DoobieG 01-29-2010 04:52 PM

OK thanks all, I thought that is what it was, just wanted to make sure.

This is why I am asking. First of all, the house was built over 50 years ago and I measure 6'4" from the nose of the last step, to the basement ceiling. I realize that the codes were different back then when the house was built. When we go to sell the house, if we ever do, would we be required in Michigan to modify the stairs? We purchased the home over 15 years ago and it was not a problem then.

Second question is, and this is what I really want to do – we have been talking about this for a while, we want to just flip the lower part of the stairs around 180 degrees and make the stairs go straight down into the basement instead of doubling back as they are now. So in essence the lower part of the stairs would be replacing the landing and the stairwell would be about 36 inches wide (plus the 4.5" thick wall approx 36 in ch high that runs around the stairwell on the main floor), instead of around 72 inches wide plus wall, which is what it is now. There would still be no ceiling over the stairs, except that last step that probably will end up going under the basement ceiling.

If I do this, and my headroom for that last step is the same as it is now, say 6'4" or maybe even an inch or two higher, do you think that would be a code violation? Since It would not be any lower than it is right now (or maybe it would even end up a bit more clearance)?

If we did this we would gain about 30 square feet both on the main floor and also in the basement.

I would like to try to avoid cutting into a floor joist for the extra head clearance, because we have joist panning for a cold air return in the basement ceiling right up against the opening of the stairwell, so if we cut an extra 16 inches into the floor and elongate the stair way for the extra head room, we would lose 1/3 of the total air flow for the duct and some floor space as well.

Thanks for any input.

 wnabcptrNH 01-29-2010 04:59 PM

If it was like that when it was built you are fine. Once you touch it you will need to bring it up to code. If you don't pull a permit you should be fine but you also are risking smacking your head.

 nap 01-29-2010 05:03 PM

If something was in compliance when it was built, most areas do not require any issues that are now non-compliant with the current codes to be corrected. Dang, if it were like that, there aren't many homes built that would be able to be sold anytime in the future without a lot of work.

I say generally because some areas require certain aspects of a home to be upgraded upon sale. We have an area that requires the electrical to be compliant with current codes as one example.

If you alter the stairs, the new installation will absolutely be required to comply with current code.

this is something that is often a local issue and to get an absolutely clear (at least as clear as the gov gets) would be to ask the local code office but I would believe the stairs, if not altered, would be just fine.

 DoobieG 01-29-2010 05:05 PM

Yeah I figured that.wnabcptrNH, I was wondering, maybe if I altered the riser height and or the width or I guess you call it the tread of the stair, do you think I could make code?

Each one of the steps rises about 7 5/6", and there are 11 steps into the basement, not including the main and basement floors...

 wnabcptrNH 01-29-2010 05:09 PM

you mean 7 5/16" right? Depending on the town some dont want more than 7.5" but definitely no more than 8" (i typically stay below 7 3/4"). Find out what the max rise in your area is. Also note if you touch the stairs most old stairs treads dont meet new code either.

 DoobieG 01-29-2010 05:16 PM

Oops that was a typo I measured 7 5/8. Actually it's closer to 7 3/4.

Well, I was told a few years ago by our building department in my city, that they use the 2003 Michigan building codes, and the Mich code says a Minimum tread of 9". Our stairs are 10 inches wide or I guess I should say 10 inches deep.

So if I narrowed the stairs by an inch to the state of Michigan minimum of 9 inches, do you think I could make that cieling clearance of 6'8"? Because that would save me 11 inches, the last step may not even make it to the basement ceiling.

 Gary in WA 01-29-2010 05:48 PM

Just don't count the nosing overhang when measuring, page 5: http://www.stairways.org/pdf/2006%20...C%20SCREEN.pdf

Angle measuring, page 4--- photo 4.

Be safe, Gary

 DoobieG 01-29-2010 05:55 PM

Yeah, actually my tread is 9" wide already, guess I can't go any shorter than that.

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