The only difference between a simple staircase and the one with a landing is that you have to build the later ones as two separate stairs and join them together. This can be tricky job, as you will need to be very precise while taking all the measurements.
First of all, you need to measure the distance from the ground to the first floor of your house. This will be the total distance your stairs have to travel.
You have to put the measurement taken into the stair formula to calculate the exact height of each step of stairs. Suppose the measurement comes 108 inches. Divide the distance by 7 and you will get 15.428, which tells you that you will require about 15 risers to reach the first floor from the ground. Now divide 108 by 15 and you will get a figure slightly above 7, which will depict the height of each riser you need to cover this distance.
Since you know the total number of risers and the exact height of each of them, you can easily plan how high your landing should be. Suppose you decide to start the landing from 30 inches.
Now you know each riser should have a height of 7 inches, you can easily decide how high will be in the landing i.e. either 7 x 3= 21 inches or 7 x 4= 28 inches. It entirely depends how many steps you want to build in the landing.
You will need two separate stringers for the upper staircase and the landing.
Use a carpenter’s square to measure and cut the 2-by-12 beam into stair steps. A skilsaw can be used for this purpose.
Make the landing and stairs first, so that the rest of the work is made easier. Cut out the first stringer and then the second one with the same method.
When the landing is made, it is easier to hang the upper stringer in its place. Then you need to cover up the landing with plywood and after that, affix the treads on the stringers.