Help with stairs?

[Kat]

Hi guys! I'm very new here. Been lurking, but only for a few weeks. Anyway, we bought the 1 1/2 story plan and want to extend it to 24 x 36 (or maybe 34 or 32, still working on that part) and we're playing around with the floorplan. We've been using a free site that has all the little icons that come in standard sizes but you can also change the sizes. Anyway, how do you figure out the size of the stairway? Some of this stuff I can figure out, but stairs have always seriously confused me. I'd like to get things to where I can post the plan here (if I can figure out how) and have you all point out all the things we missed.  

So, how do you figure stairs? They'd be in an L shape if that helps any.

[John Raabe]

The 1-1/2 story plan comes with an "L" shaped cottage stair but that will likely be too steep for the larger house you are planning.

Have you seen this article on modifying plans? http://www.planhelp.com/public/92.cfm. The software programs linked there can do various stairways on their layouts.

Here is another set of downloads from the PlanHelp site that might be helpful: http://www.planhelp.com/public/programs/downloadsearch.cfm?keywords=stair&searchtype=keyword&searchmode=keyword&cat=all&sortby=recent&search=search

[Kat]

I followed the links and it seems you have to be a member of plan help? I have an older Mac for a computer, would I be able to use all the stuff on there? Thought I should find out before I spent money.  Thanks!

[dug]

I'm no authority, but I just sketched mine out on graph paper (I am building 20 by 30 1 & 1/2 story).

Figure out  the total height from bottom floor to loft. Then decide how much rise and run you want for the steps. Standard stairs are something like 7 1/4 in. rise and 10 in. run (don't quote me, I'm going from memory). You could probably go with a little more rise and less run than that if you want to make them a little more compact, depends on your local code requirements. I don't think you would want more than about 8 in. rise, as climbing stairs becomes a bit awkward beyond that.

Then it's just a matter of doing a little math to figure how many risers you need to get to your loft height. You'll probably have to change them one way or another in order to make it come out right.

I am going to build mine (L shape) using about 7 1/2 in rise and 10 in. run using 14 risers. 5 steps to the landing (where stairs change direction). Landing is about 37 in. If stairs start parallel to the long wall (as mine will) that is about as high as you can go as the roof will start to close in on you as you go higher.

Width is another matter, I am going with 36 in. (standard in normal home) to make it easier to move stuff upstairs.

Hope this helps, and makes sense.

[MountainDon]

dug nailed it.  Start by measuring or calculating the total rise from one floor to another.

The maximum IRC code allowed riser height is 7.75 inches. The minimum run is 10 inches. There are other rules regarding nose over, width (36" minimum), dimensions on winders and landings, maximum allowable variance between tallest and shortest risers (3/8"). Section R311.5 of the IRC has the full list. Minimum headroom is supposed to be 6'8" as measured from the stair tread nose to the directly overhead ceiling surface.

I was going to attempt a blow by blow description on how to calculate the risers and treads, but am taking the easy way out. There's a staicase calculator at blocklayer.. Click Here.   Remeber to enter code appropriate values and play around with it to gain some understanding.

It is set to make a straight run staircase, but that should be easy enough to think through.


There is also a useful document at...
http://www.stairways.org/pdf/2006%20Stair%20IRC%20SCREEN.pdf

[Jens]

Calculating stairs can be pretty easy.  First thing you need is you total rise.  If you are going subfloor to subloor, and both floors will have 3/4" flooring this is easy, just measure.  If the floors will be of different thickness, you must find the difference and factor that in (i.e., first floor is hardwood 3/4", second floor is carpet 3/8", difference of 3/8" will be subtracted from measurement during rough phase).

This is how I do it, let me see if I can explain it easily. 

total rise=104" (assuming 8' walls, 2x8 floor joists, and 3/4" decking).  Divide this by your 7.5" ideal rise. 

  7.5
104           =13.86

We can't do a fraction of a step, so round the answer up (giving us one more step, which makes the rise shorter)

14 steps is our answer.  Now we need to know how big the rise is.

104/14=7.428   or roughly 7 7/16" per riser.

If the landing will be the top step, then you can subtract one riser when cutting your stringers.  Take your total number of treads, and multiply it by tread depth to get the total run.  Like Don said, 6' 8" is the minimum headroom above the nosing.  Even this can feel cramped.  I would suggest 7'6" minimum for comfort, and if possible just make it all open above.

If you don't have your finished flooring in yet, you have to make adjustments in your cutting layout, and you also need to make adjustments to your stringer cuts depending upon the thickness of your finished treads before cutting the stringers.  I could go into that more if you like, but I am not usually sure if I am ever clear enough or just confuse people.  It's all so clear in my head, and when I hear it come out of my mouth, but then people seem to get confused.

[Kat]

Wow, guys, Thanks! That does makes sense to me. I think I might even be able to figure out the adjustments for flooring. One question though, what is the nose/nosing you all are talking about?

Oh, and is there a federal code or something like that? We have no restrictions except electrical here, but we would like to build up to some sort of code. 

[Redoverfarm]

Check on Page 7 of this site for the "bull nose".  It also has some other code references about the design.


http://www.stairways.org/pdf/2006%20Stair%20IRC%20SCREEN.pdf

[MountainDon]

The nose is that portion of the tread that overhangs the riser. Having that makes stairs easier to negotiate the stairs.

I"d suggest you use that link to the illustrated code as a basis for dimensions. If you have no special rules to build to it will be a good guide. The stair code has been refined over time and for the most part there are solid reason behind it. Thirty six inch side stairs are easier to move furniture and boxes up and down. The riser heights and tread sizes "fit" most people best, making the stairs safer.

The IRC is a code adopted my many states and municipalities.

http://countryplans.com/smf/index.php?topic=2590.0
http://countryplans.com/smf/index.php?topic=6224.0

[stairman]

most states have modifications of the IRC codes.  For example NJ allows for a 9" cut size on the treads with a riser height of up to 8.25"

[John_M]

A lot of people ask about stair codes and try to fit the narrowest, steepest steps they can into their structure.  My best advice is to think long and hard about who is going up and down those stairs, not only now, but in the future.  Small children, guests, etc??  Also, realize that people get older over time and those who can get up or down those stairs easily today, may not get down them as easily in 2, 5, 10 or even 20 years.

[MountainDon]

stairman, above, represents a company in PA that makes some nice spiral stairs going by the pictures on their website. I know that many of us here "roll our own" for just about everything.

Anyhow stairman and I/we met because of an perhaps overzealous search engine optimizer they recently contracted with. Earlier today or late last night several posts were made by one of those new members who just happened to pack their signature line with a load of advertising links. Those are gone but Rich from Stair-Pak truly did not realize what was going on. He seems like a nice straight up guy with a nice product that could be interesting or useful to some.

So I'm placing a link to Stair-Pak in the Referral Links board

http://countryplans.com/smf/index.php?topic=8537.new#new

[stairman]

Thanks Don,

I would be glad to offer help on any type of layout or code questions for the board members, not just on spiral stairs but straight stairs as well.  Feel free to e-mail me if you have a question.

Rich

[Jens]

Stairman, do you think that my explanation was decent?  I guess some other members would probably be the best judges of that though.  I often have a hard time getting the stuff that is in my brain out.  Here's your chance for a yuk, yuk, Glen...or PEG...or just about any of you, I guess.