Building DIY stairs is usually not a difficult task, but special care must be taken to prepare for the project ahead of time by taking careful measurements and choosing the right materials. The rise and run of the staircase will need to be determined ahead of time; this will dictate the length and height of the staircase. Formulas for determining the rise and run can easily be found by doing an Internet search; make sure to take these measurements and check them again before buying any materials for the DIY stairs.
Once the rise and run have been determined, it's time to choose the best materials for the job. DIY stairs can be made from a variety of materials to suit many needs. Outdoor stairs will require different materials than indoor stairs, so start by determining where the staircase will be. If the DIY stairs will be anywhere that moisture can build up, such as in a damp basement, pressure-treated wood will be necessary. Outdoor wood staircases should also be made from pressure-treated wood, or from woods that are naturally resistant to water damage, such as cedar or teak. The project budget may dictate which woods are most appropriate for a particular space as well.
Remember to consider railings when building DIY stairs. For safety and stability, railings should almost always be present along a stairway, thereby preventing falls. Railings should be built at a comfortable level for an average size adult, and they should be secured properly into wall studs or into the stairway stringers using vertical posts. In either case, the railing must be stable and made from a material that can withstand the pressure or weight from a fully grown adult. An unstable railing is less safe than no railing at all, so it is important to make sure this component is properly secured.
Consider the safety of each tread once the entire staircase is built. It is sometimes possible to increase the grip of a tread by affixing friction materials, or by using textured paints specifically designed for porches and decks. This is a good idea if moisture will get on the stairway, or if ice is likely to build up at any point. Adding stains, varnishes, or water-resistant treatments is also a good idea, especially for outdoor staircases that will regularly be exposed to the elements and foot traffic.