- Rest the end of a straight 8’ 2×4 on the top of the doorsill and use a level to bring it to a level position.
- Depending on your choice of step, refer to either the 7” or the 7 1/2” chart below and measure out the appropriate distance from the house.
- Keeping your 2×4 level measure the drop to the ground or finish grade.
- Take the number you have just measured for total drop and find it in the total drop column. Look two columns to the left and find the number of risers you need. The column in between will give you the height of the unit you need. Remember to allow for a step up from the top of your new step.
The illustration to the right shows that at 66” away from the house the ground is 28” below the top of the threshold. Look at the total drop column and find 28”. Now look two columns left and you will see that for a 28” drop, you need three risers. If you look at the step height column for 7″ rise steps you will see that a three riser is 21” tall. This will leave you a 7” step up from the platform to the threshold. If you follow the 3 Riser row all the way over to the right, under the 42” platform depth column you will see that the total projection from the house for this step is 66”. It is important to measure here because this is where you step from the ground onto the first tread. Measurements for 7 1/2″ steps are in the chart below.