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-   -   Am I SCREWED? Stairs & building code. (http://www.diychatroom.com/f19/am-i-screwed-stairs-building-code-22684/)

Armitage 06-23-2008 01:39 PM

Am I SCREWED? Stairs & building code.
 
I'm in the process of completing a largish (1400 ft^2) 2 story addition on my home. Don't even ask when the first permit was pulled - life intervened for awhile.

Anyway, I recently removed the window and wall from the existing house to make the entrance for the addition. There is a landing there that goes down one step into the 1st floor of the addition, and the steps to the 2nd floor go up from this landing also. I'll post a picture later - this is probably hard to visualize.

Anyway, this landing and the stairs were done several years ago, and somehow I screwed up the height of the landing wrt the inside floor AND the first step http://images.ih8mud.com/images/smilies/oops.gif

Call the landing height 0:
Height of interior hardwood flooring: 1 1/4"
Height to top of first stair: 8 1/8"
Height of other stair risers: 7 5/8"

So - to match the riser height on the first step to all the other risers, I only have room for 0.5" of flooring. PITA, but not impossible. But that will leave me 3/4" below the level of the interior floor http://images.ih8mud.com/images/smilies/bang.gif

The building code is based on the 2003 International Building code (with ~140 pages of adjustments & exceptions). As I understand it, the max allowable deviation in riser height is 3/8" - so I could possibly get away with 7/8" of flooring and be left with only 3/8" height difference between the landing floor, and the floor of the existing house.

So - any suggestions? Any other loopholes I might be able to take advantage of?

Raising the stairs is not really an option - they are seriously tied into everything. Hardwood stairs also - so adding height on top of the treads isn't feasible either.

Will the difference in floor height be an issue? It will likely be somewhere between 1/2" and 3/4" and I can make that transition over approximately a 6" width.

Thanks!

47_47 06-23-2008 02:33 PM

What is the maximum rise you have and the maximum rise allowed by code? This maximum rise cannot be exceeded. I believe you will have to replace or move your stringers.

Added.
Do not make a 1/2"-3/4" ramp. This will be more of a trip hazard than a high step.

Armitage 06-23-2008 03:20 PM

1 Attachment(s)
Here's a quick sketch...

Armitage 06-23-2008 03:32 PM

Quote:

Originally Posted by 47_47 (Post 132982)
What is the maximum rise you have and the maximum rise allowed by code? This masximum rise cannot be exceeded. I believe you will have to replace or move your stringers.

Added.
Do not make a 1/2"-3/4" ramp. This will be more of a trip hazard than a high step.

My max rise is about 7 5/8. I believe the max rise allowed by the code is 8" - I need to get a look at the original code + our local amendments, which should happen tomorrow.

I agree regarding the 1/2 -> 3/4 ramp. I think I'd prefer to have the floors flush, and the first riser 3/4" shorter then the rest.

Not perfect of course - but tearing out & redoing these steps is likely thousands in materials and 2 months of work at the hours I can put toward it. Makes me sick to my stomach just thinking of it.

47_47 06-23-2008 03:35 PM

Let me get this straight, you have 8-1/8" from the finished top of the first tread to the top of the subfloor and your finished floor is 1" thick.

TexasEd 06-23-2008 03:36 PM

Well you eliminated my first option of adding height to the top of the treads.

Could you use thinner hardwood flooring or get the inspection done before the hardwood goes down?

Armitage 06-23-2008 03:55 PM

Quote:

Originally Posted by 47_47 (Post 133008)
Let me get this straight, you have 8-1/8" from the finished top of the first tread to the top of the subfloor

Yes
If it were done right, the subfloor should be 1/2" higher then it is now - the addition of 3/4" of flooring would then make it flush with the existing interior floor.
And the finished top of the first step should be 3/4" higher then it is now - which would make it 7 5/8" higher then the finished landing floor.

Quote:

and your finished floor is 1" thick.
No, the finished floor is 1 1/4" (1/2" subfloor + 3/4" hardwood) above the subfloor of the landing. A distinction without difference I guess.

Armitage 06-23-2008 03:59 PM

Quote:

Originally Posted by TexasEd (Post 133009)
Well you eliminated my first option of adding height to the top of the treads.

Yea - the stair treads are hardwood anyway. Might have been an option if they were carpeted.

Just entertained the idea of putting a carpet runner down the steps, under which I could raise the height of the tread. But I'd need 3/4", which is to much, and would then screw up the height at the top step (which I do have right). If I'm going to have a short step, I'd prefer it at the bottom.

Quote:

Could you use thinner hardwood flooring or get the inspection done before the hardwood goes down?
Yes I could plane down the hardwood - or even chop out the landing subfloor and lower it. But that just makes the difference from exisiting floor to the landing subfloor that much worse.

Termite 06-23-2008 04:35 PM

Ok...

Per the 2003 IRC, your maximum rise on a stair is 7-3/4". 3/8" variance is allowed between any two rises, but no rise can exceed 7-3/4". A hump in the flooring on the landing (top or bottom) would not be permitted. The landing has to be flat and level for the first 36" from the top or bottom stair nose.

Termite 06-23-2008 04:36 PM

Quote:

Originally Posted by TexasEd (Post 133009)
...or get the inspection done before the hardwood goes down?

Hehehe. I've seen that tried before. :no:

Clutchcargo 06-23-2008 04:36 PM

I believe the code calls for the max between the shortest riser and tallest riser to be 3/8" but you can only be 1/8" off between 2 adjacent steps.
Is the landing actually the first floor or is there one more step off the landing?
If I understand correctly, can't you just add a layer of ply over the landing?

Termite 06-23-2008 04:43 PM

Quote:

Originally Posted by Clutchcargo (Post 133047)
I believe the code calls for the max between the shortest riser and tallest riser to be 3/8" but you can only be 1/8" off between 2 adjacent steps.
If I understand correctly, you may be able to just rebuild the landing.

Not true. The code allows 3/8" variance between any two steps on the flight of stairs. As an inspector, I can measure the top and the bottom and compare them, or I can randomly choose two other rises...Adjacent to each other or not...And they have to be within that 3/8" range.

Examples:

Top rise 7".
Bottom rise 7-1/4".
All other rises 7-3/8".
Not a problem.

Top rise 7".
Bottom rise 7-1/4".
Most other rises 4-1/4.
One riser 7-1/2".
Problem.

Armitage 06-23-2008 04:49 PM

Quote:

Originally Posted by thekctermite (Post 133045)
Ok...

Per the 2003 IRC, your maximum rise on a stair is 7-3/4".

Would you happen to have a section reference for that? My local code makes the following exceptions, which I think refer to riser height, but I can't confirm until I go to the library to look at the code.

"RBC303.4.24 Section R311.4.3. In the exception after the second paragraph, delete “7 inch (196.85 mm)” and replace with “8 inch (203.2 mm).”

RBC303.4.25 Section R311.5.3.1. In the first sentence, delete “7 inch (196.85 mm)” and replace with “8 inch (203.2 mm).”

Quote:

3/8" variance is allowed between any two rises, but no rise can exceed 7-3/4". A hump in the flooring on the landing (top or bottom) would not be permitted. The landing has to be flat and level for the first 36" from the top or bottom stair nose.
Yea, I don't plan any hump directly in front of the stairs. What about a 3/8" to 3/4" ramp from the landing into the existing house? Certainly not ideal, but I'm grasping here.

Armitage 06-23-2008 05:02 PM

Never mind on the code reference for max riser height - my issue isn't the max riser height, but rather the max variance. If it's 3/8" between any step, and my max riser now is 7 5/8", then the lowest I could could go on that first riser would be 7 1/4" Which means I could put down 7/8" of flooring (1/8" plywood + 3/4" hardwood) which brings me to within 3/8" of the interior floor.

What do you guys think about a 3/8" -> 3/4" ramp over 6" as you go from the landing into the existing house?

Termite 06-23-2008 05:05 PM

You've got the hang of rise variances.

If the ramp is located within the 3' required landing, it would not be allowed. No portion of a landing can exceed a 2% slope, which equates to 1/4" maximum slope per 12" of landing.

If it is not in the landing, but out in the floor of the house, it would be allowable.


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