Building Flaired/Fanned Stairs Next To Square Stairs

RKDO

I'm building a small deck with a set of stairs that go straight up on one side of a platform (the right side) and flaired on the left side of the platform where they meet in the middle or the corner of the platform deck. I hope that I am explaining this clearly enough.

The deck is 32 inches off the ground, the stairs on the right come out about 4 feet. I wondering what the best method would be to connect the two sides so as to blend them well. The left side or flaired side can only be about 2 feet at the bottom and 1 foot at the top.

I'm having a little difficulty working out the angles and the placement of the stringers in order to have the steps all come neatly together.

Any help is appreciated, thank you.

Ahren

RKDO,

Do you own a scientific calulator? And if so, do you know how to use the trig. functions? (SIN, COS, TAN) You can use them to find the angle to bevel the plumb cuts on your stringers and to find the angles at which you're going to have to cut the ends of you treads to. It's hard for me to explain it here in words. Maybe someone else can jump in and supply a drawing?

I'll do my best:

When you have a triangle that you want to find the angle of, you can use trigonometry to do this.

So you have a right angle triangle, right? There are three sides and three angles. The two sides that make the right angle are the legs, and the third side is the hypotenuse. You know that one angle is 90 degrees. If you want to find the other two angles, remember this anagram: SOHCAHTOA.
So if you're looking at a particular angle of your tringle, you have one leg adjacent to the angle, one leg that's opposite the angle, and your hypotenuse. The SIN of the angle is the opposite leg divided by the hypotenuse. The COS of the angle is the adjacent leg divided by the hypotenuse. And the TAN of the angle is the opposite leg divided by the adjacent leg. S.(sin)O.(opposite)H.(hypotenuse) C.(cos)A.(adjacent)H.(hypotenuse) T.(tan)O.(opposite)A.(adjacent). S=O/H C=A/H T=O/A.

So, in your case, you take a plumb bob and drop it to the ground where the top of the flared stringer is going to meet the deck. Put a nail in the ground. There's the first point of your triangle. Put another nail in the ground at the outside of where the flared stringer is going to meet the ground. There's your second point. If you know that the top of the flared stairs is going to be a foot away from the straight stairs, stretch a string that is square to the deck from the first point. Then take your tape and butt it into the side of the staight stairs, and where the 12" mark intersects the string, that's your third point. Stick a nail in. You now have your triangle. I hope I haven't confused the hell out of you.

You now have a right angle triangle that you can work with. You can now measure the two legs and the hypotenuse of it. You want to find the angle that is closest to the deck. We'll use the TAN of the angle here. Take the length of the side opposite the angle, and divide it by the length of the side that touches the angle. Use the two legs that make the 90 degree angle with each other. That gives you the TAN of the angle. To find the angle, take this number and push (shift) then (TAN) on the calculator(TAN-1)or(ArcTAN). This is the angle in degrees. That's the bevel to set your saw at to make your plumb cuts.

I really hope this is helping. I know it sounds desperately complicated, but if you learn the trig. functions you can solve many angle mysteries.

BuiltByMAC

RKDO, not following your terminology - can you post a drawing of your project? Are your steps flared - pie wedge shaped?
Is your staircase itself growing in size on one side - 6' at the first step and 8' at the top step, all growth along one side? With only 32" of height, you could do a bunch of things. It'd get a lot hairier if it was elevated!

Ahren, I got some of what you posted, can honestly say I don't usually jump into those equations for my designs. It's been a long time since tests in school!

Mac

RKDO

Thanks guys for the help. Ahren, I'll have to go dig up my scn calculator and give it a go. Mac, I'm working on getting some pics or drawings up ASAP.

Thanks again, I'll let you know how it goes.
-RKDO

Joe Carola

Can you post some kind of sketch in plan view. I'm sure a couple key strokes on the Construction Master Calculator can help you.

__________________
Joe Carola

Ahren

I drew up a picture to help clarify my post. I come from a math/science background, (I went to school for engineering) and have become accustomed to my own methods. I was going to suggest that you post your question in the framing forum, because you are going to have to treat your stringers in the same manner as roof hips. The framers in here will probably be able to answer you easier than I can. I do few roofs, mainly simple shed and gable roofs. I rarely run into oddball angles, but I use trig. to figure it out. But a drawing or picture from you is certainly going to help visualize your situation. Anyway, here is my picture:
It shows how to solve an angle using the SIN, COS, and TAN. I used the good ol' 3-4-5 triangle as an example, but it will work for any triangle. You can find any angle as long as you know two sides.