Stair Design

Let us begin with a picture showing the four platforms as I left them on Saturday.

Imagine putting a set of stairs between platform one and two. Let us draw a diagram for illustration. To do this I open up Power Point and use the insert shapes tool and draw what I want. I then copy my drawing to Paint and save it as a picture to my Miscellaneous Source picture folder. That way it is in a form I can easily use with blogger.

You can see the two platforms. Draw a triangle between the two, extending it onto platform one far enough to allow the rise of one step. That top line shows where the lumber will go to carry the steps - true only if the floor has been installed on the platforms. If it hasn't then raise the top line of the large triangle the thickness of the floor. The right side of the large triangle is called the "rise" and is the total vertical distance between the two platforms, which in my case was conveniently set at 40 inches. The horizontal distance between the two platforms happen to work out at a nice 44 inches. Divide the rise into five equal eight inch segments. Where the horizontal lines intersect the hypotenuse of the large triangle, draw in a vertical line. This process creates five identical triangles that represent our five steps each with a rise of eight inches and a run of eleven inches - one run extends out on the lower platform. We will take a length of 2 x 4 and clamp it in place to represent the hypotenuse of the triangle, making adjustment for the floor thickness. That 2 x 4 helps us see what we are doing.

The above picture shows the 2 x 4 in place to represent the top of the stringer. Measurement shows we will need a piece approximately five foot four inches in length. That means we can get both sides out of one twelve foot length with some waste. We will need two twelve foot lengths for the two large sets of stairs. The bottom stairs will require a piece ten foot long.

In the above picture I clamped my carpenters square to the 2 x 4 so I could take a picture of it. The two black dots on it are position clamps that mark the eight inch rise and the eleven inch run. The triangle formed by the two little position clamps is the second one from the top in the diagram above. You can slide the square down the 2 x 4 and mark each step. We will do this on the stringer when we install it later. Let us look at a close up of the square.

If you carefully connect the horizontal and vertical lines you will end up at the right place at the bottom of the stairs. I will show you this when we layout the stringers for the next entry. If you look at the inside numbers on the square you will see eight at the top right and eleven at the bottom left. The square has numbers and tables on both sides that have special application, primarily in roof construction. The square is a valuable tool, but so are those little clamps when laying out stairs.

That wood extension ladder was purchased back in the mid 60's and has been used to build four houses over the years. I also have a large 32 foot extension ladder. I needed it to safely reach the top of this house when I built it.