Wooden stair stringers come in a variety of woods and options. The stringer is basically the backbone of any staircase. They are the notched pieces of wood that run for the entire length of the stairs and support the steps (also called treads) of the stair. You can buy untreated or pressure treated wood, as well as stringers that are pre-cut and easier to use. This article will outline the different types of wood stringers available for stairs.
1. Pre-Cut Stringers
This is most likely the type of stringer that a do it yourself handyman will use. The stringer is the most complicated part of the stair, if you get even one notch just a little bit off it can cause your steps to creak and be unstable. To solve this issue, most hardware stores are now offering pre-cut stringers. All you need to do is give the hardware store your measurements and they can point you to the right stringer. This will take most of the difficulty out of building your stairs. Once the stringers are up and secured, everything else will fall into place.
2. Uncut Stringers
If you decide that you want a challenge, or your floor-to-floor height is an unusual number, you may end up cutting the stringers yourself. You should use either 2-by-12 or 2-by-14 wood for stringers. Also, since different grades of wood are available for residential building, you need to make sure that you are either buying number 1 or select grade materials. Also be careful to examine the wood before you buy it to make sure that it is straight and doesn't have an excessive amount of knots. Always cut the first stringer to your specifications and then use the first stringer as the template for the other two.
3. Pressure Treated
Pressure treated stringers are the main choice for decks and other outdoor stairs. The pressure treating will help the stair resist damage from termites and fungal decay for decades. In fact, some producers of pressure treated wood will offer warranties that extend for the life of the purchaser. Despite the availability of naturally durable species such as redwood and cedar, many still use pressure treated wood for it's economical benefits. One thing to be aware of is that just because wood is pressure treated, it doesn't automatically make it better. There are still different grades of pressure treated lumber, you still need to go with a number 1 to make sure that you don't have excessive knots or splits.
While metal is obviously not a type of wooden stringer, since metal stringers are becoming more common, they are worth mentioning in an article about stringers. Metal stringers do have distinct advantages over wood, and some disadvantages. The first advantage would be that the notches are molded rather than cut. That lessens the likelihood that there will be discrepancies. Metal stringers are also easier to install than wood stringers. They can just be easily bolted to both the upper joists and kickboard. Disadvantages include the limited indoor only use. You don't want metal to be exposed to the constant outdoor elements, so you would be limited to using metal stringers indoors in a consistently dry area.