Replies

1. 
   CapnMac | Jun 11, 2008 09:05am | #1

   take the 118-1/4 and divide by 16 is where I run into problems. I get a decimal and can't figure how to make it come out to what the county wants:

   "the largest rise or run within any flight of stairs is not to exceed the smallest by more than 3/8" -- whatever that means

   So close, you skipped on the one last step.

   You found the 16 risers.  118.25 ÷ 16 = 7.390625  Closest fraction to that is 7.375 (or 7 3/8").  Take and multiply the usable height by risers.  That's 7.375 * 16 = 118"  118" is 0.25 < 0.375, the 3/8" maximum cited, so that's good.  My preference is to "bury" the "off" step at the bottom, as that is the least high trip distance.  Other's differ, though.

   Oops, we have an error though.  We really need the finished floor to finished floor height.  Unless you are thinking of having a 1/4" VCT floor in the basement, which would make the finished run 118" even and no problem at all.

   So, if you were installing 1.5" of tile floor in the basement, the run then becomes 118.25 - 1.5 = 116.75"  116.75 ÷ 15 = 7.783, around 7 7/8, which is a hair steep.

   So use 116.75 ÷ 16 = 7.296875 which would be bad.  7.25 * 16 = 116  116.75 - 116 = 0.75 > 0.375 = fail. 

   So use 7 5/16" or 7.3125 * 16 = 117"  117 - 116.75 = 0.25 < 0.375" = Pass

   That help any?  Or just muddy the water more?

   Occupational hazard of my occupation not being around (sorry Bubba)
1. 
   buckteeth | Jun 11, 2008 05:09pm | #11

   hey all,

   thanks. tons of great advise.

   capnmac,

   muddy water - no good stuff - thanks. and i like the 'off' step being close to the floor. we were just planning on staining the floor (a good article in fhb a while ago) but maybe code won't allow that either nowdays.

   dovetail,

   thanks for the link and you'll get to keep the bones as i'm not that good.

   piffin,

   we did think about a spiral but my wife's knees can't handle the rise. called one of those guys in fhb and they said 8-9" rises. so we'll have to go with 16 at 7 1/2". she would like 7 or less, but there is a glb in the way.

   hammer,

   where i'm at min run is 10"

   ted,

   wow, what a cool link. and that info brings up another question. i've seen the stringers cut ou and then i've seen stringers with metal brackets where the treads are then placed on the brackets. which is better? and which is easier for a 'semi' mildly skilled guy?

   msa,

   something i've wondered about. so i should measure beginingg and ending places?

    

1. 
   MSA1 | Jun 11, 2008 11:06pm | #12

   With an uneven floor, I would figure out about where the stairs will land. Then if you can, (what  i've done) is use a straight edge to transfer upper floor height to above where you think the stairs will land. Then measure height from there.

2. 
   Ted W. | Jun 12, 2008 12:27am | #14

   ted,

   wow, what a cool link. and that info brings up another question. i've seen the stringers cut ou and then i've seen stringers with metal brackets where the treads are then placed on the brackets. which is better? and which is easier for a 'semi' mildly skilled guy?

   I've only done open stringers (cut zig-zag) and closed stringer (routed out), never brackets. But I would imagine the brackets would be way easier for anyone, not just the novice. I couldn't see selling my customers on that, unless it's specifically what they want as part of the design. But surely it's got to be easier.--------------------------------------------------------

   Cheap Tools at MyToolbox.netSee some of my work at TedsCarpentry.com

3. 
   Piffin | Jun 12, 2008 01:07am | #15

   As you plan your layout, be sure to consider the size of run of the hole in your floor now, and the depth of that floor. You need to have a minimum 6'8" so nobody bumps their head and knocks themselves out on the stairs 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

2. 
   dovetail97128 | Jun 11, 2008 09:42am | #2

   Excellent start!

   You are definitely on the right track and as Capn said just one more step.
   After dividing the 188 1/4" by 7 1/2" you actually get 15.76667 as a number of rises.
   Since you can't have .76667 of a rise you need to round up to the next whole number , or 16 in this example.

   Now divide 118 1/4" by the 16 and you get 7 3/8" (actually the exact answer is 7.390625" or 7 25/64", 3/8" is close enough, 13/32" would be closer) as the figure for your rise for each one.

   Now you have no uneven rises to contend with at all.

   Here is a link for fraction to decimal conversion.
   (You can use it and convert your decimal to the correct fraction and then if you can cut your stringers exactly to that amount I will personally give you a pile of milk bones!)

   http://www.webmath.com/dec2fract.html

   They can't get your Goat if you don't tell them where it is hidden.
1. 
   jarhead2 | Jun 11, 2008 11:31am | #3

   At least I know where the webmath link came from!

   Good work. 

    

    

    

   “Some people wonder all their lives if they've made a difference. The Marines don't have that problem.”                Reagan....

   Failure is the condiment that gives success its flavor. -Truman Capote

1. 
   dovetail97128 | Jun 11, 2008 04:59pm | #9

   Yeah , sorry about that.
   They can't get your Goat if you don't tell them where it is hidden.

2. 
   MikeSmith | Jun 11, 2008 01:17pm | #4

   buck.... multiply your decimal portion times 16... that will give you the nearest 16thseg...... 7.25.25 x 16 = 4 or 4 /16 ( 1/4 )Mike Smith Rhode Island : Design / Build / Repair / Restore

3. 
   Piffin | Jun 11, 2008 02:09pm | #5

   15 risers are 7-7/8" each

   16 risers gives you 7-3/8" each

    

    

   Welcome to the
   Taunton University of Knowledge FHB Campus at Breaktime.
    where ...
   Excellence is its own reward!

4. 
   hammer1 | Jun 11, 2008 03:09pm | #6

   There are two things to think about with stairs. The total rise, which is what you have posted and the total run, which you have not. A basement stair is a utility stair, the rise can be a little higher and the tread a little shorter than you might use for a formal stair. There is a balance between the two that effects your walking position, Essentially, the shorter the rise, the longer the tread. A rise of 7 3/8" is a bit short for a utility stair, with 15 treads at 10" that brings the stair out 12' 6". You need head clearance of 6'6" from the tread to the header at the end of the framed opening. 10" is very short with a 7 3/8" rise.

   You could use 15 risers at 7.88", that's 7 7/8" plus, less than 1/64". This will allow you to use a shorter tread and reduce the total run length. 9 1/4" would work for your run with a finished tread at 10". This allows a 3/4" tread overhang. The total run of the stair would be 10' 9 1/2". Something to think about if you stair run is restricted, going the width of the house rather than the length. You don't want the last step ending at a foundation wall. In tight situations, the bottom tread can actually be a platform. This is a common problem when you have less than 12' from the carrying timber to the foundation wall.

   When they say "the largest rise or run within any flight of stairs is not to exceed the smallest by more than 3/8" they mean that risers should all be equal height but cannot vary more than 3/8", the same with tread widths. A riser in the middle of a stair that varies from the others by 3/8" is a tripping hazard. If the top or bottom riser varies by 3/8" from the others, it won't break your cadence when walking the stairs and cause a person to trip. Most of us try to do the math so alike parts are equal.

   To get decimal equivalents of a fraction, you divide the top number by the bottom one. 1/64" = .015, 3/4" = .75.

   Beat it to fit / Paint it to match

1. 
   Ted W. | Jun 11, 2008 03:32pm | #7

   Try this one...

   http://www.inspectusa.com/info/calc/stairs/rise_run_stringer.htm--------------------------------------------------------

   Cheap Tools at MyToolbox.netSee some of my work at TedsCarpentry.com

5. 
   MSA1 | Jun 11, 2008 03:44pm | #8

   I dont want to confuse the issue but are you measuring rise height from where the stairs will land (on the basement floor) or are you just dropping a tape from floor to floor? May not be a big deal but if your floor is out it could mean your working with the wrong numbers.

   Not a big deal level floor to level floor but with a basement be careful.

1. 
   dovetail97128 | Jun 11, 2008 05:00pm | #10

   That is a good point.
   They can't get your Goat if you don't tell them where it is hidden.

6. 
   john_carroll | Jun 12, 2008 12:08am | #13

   i can't figure out changing a decimal to a fraction that can be used on my tape measure so i can get the correct rise for my 15 steps.

   To go from a decimal to sixteenths, multiply the decimal fraction by 16. The result, rounded to a whole number, is the number of sixteenths. Examples:

   .1728 x 16 = 2.76  Round 2.76 to 3. The decimal .1728, then, is 3/16.

   .836 x 16 = 13.38. Hence, .836 = 13/16.

   .627 x 16 = 10.03. Hence, .627 = 10/16, which equals 5/8.

   To go from a fraction to a decimal, divide the enumerator (the top number) the the nominator (the bottom number). For example:

   11/16 = 11 divided by 16, which is .6875.

7. 
   MikeCallahan | Jun 12, 2008 07:09am | #16

   I always use decimals when I lay out the steps. I input the diagonal measurement into my calculator memory and then add the consecutive numbers.
   If your rise is 7.39 and your run is 11 then the diagonal is ~13.25". (Pythagorean theorem) Lay out 0,13.25",26.50".....
   This way is much more accurate. If you already know that .5 is a half and .125 is an eighth and so on then estimate the position on your tape as you lay out your marks. You can set up your framing square at 11" and 7.375" and move it up on your marks instead of stepping it. If you step using 7.375" increments, then when you get to the top you will be at least .25" off and that is unacceptable for the work that I do.

   Mike Callahan, Lake Tahoe, Ca.