On stairs, there is usually a trim board on each side of the stairs. This trim board is called the "skirt".
Usually, the framer leaves enough room between the stairs and the walls to slip in a piece of 1/2" drywall to form the skirt. You just slip in the board, nail it to the studs, and you are done.
I am remodeling my daughter's basement. Back circa 1970 when this house was built, the framer left zero space between the drywall and the sides of the stairs. I wondered how I could ever cut a 12 foot board with all the cut-outs for the stairs, and have it look nice.
These stairs eventually get covered with carpet, so my skirt boards do not need to be a perfect fit.
I Googled this topic, and found this web site. The person on the web site describes a carpenter's trick on how to make skirts that fit so closely to the stairs, that you can not even slip a $20 bill in the cracks!
In a nutshell, the carpenter's trick is:
1. Lay the board on top of the steps. Tack in place temporarily.
2. Measure each step. Find the longest rise and the longest run
3. Using a scribe stick, scribe the horizontal cuts for the bottom floor, and each step. Set the scribe at the longest rise dimension.
4. Saw out the bottom piece so the board now rests flat on the bottom floor.
5. Holding the scribe stick horizontally, scribe each step. The stick is set at the largest run dimension.
6. Draw each nose piece on the board. Using a scrap piece of the nosing is best.
7. Saw the board
8. Nail the board to the wall.
(If the web site linked above disappears, send me an email and I will send you a PDF copy that I saved)
Now usually I don't read the directions at all. A "real man" does not read the directions until he gets stuck, or has pieces left over
I actually read the directions from the web site about 3 times.
I went ahead and tried the method. Here is the 12 foot 1x12 laying on the stairs:
I did the scribing on the board. I noticed I was missing a little triangle at the corner of each step. I could not figure out why. But the triangle was small enough, it would work because the carpet will hide it.
Here is the first skirt sawed out:
My joints were not perfect. Forget the edge of a $20 bill fitting in the cracks, a silver dollar would fit into my cracks But the carpet will hide my big cracks ok, so it will work.
Here is the finish painted skirts:
Why Didn't the Carpenter's Trick Work Better?
It bothered me why this trick did not work better than it did. On the web page with the trick, there must be 20 pages of comments. I only read the first couple of pages before I made my skirts.
After I was done with the skirts, I went back and started reading more comments. One of the comments was that the person who tried it ended up with the same missing triangles that I did. The author said the person did not use the max rise and max run on the scribe sticks. Aha..........I was guilty of the same thing. I adjusted the scribe for each step, instead of finding the maximum value and using the same max value to scribe all steps.
I went into Google Sketchup and constructed a ficticious set of stairs. I had the rise and runs vary at least 1/4". I then followed the carpenter's trick exactly, and this method worked perfectly
So if you are going to use this old carpenter's trick, be sure and follow the instructions exactly. Especially to measure each step and find the max rise and run numbers. Keep the scribe stick set at the same setting when you scribe the rises, and keep it the max run number each time you scribe.
I wish I had another set of stairs to try this out one, but I don't.