Taking on a project like basement stairs may seem simple enough, but for all the ways they’re similar to ordinary stairs, there are a few key differences to keep in mind.
While any staircase needs to be built with careful measurements and safety in mind, basements are frequently dark and not constructed to standard dimensions. Therefore, an extra measure of planning is in order when constructing basement stairs.
On the flip side, one area where basement stairs require less effort is their appearance. Depending on how often you plan on taking guests down to your basement, you may not need to add any frills or work to make them pretty.
Follow these guidelines when planning the build for your basement staircase.
Step 1 - Know Local Safety Codes
Check your local building codes to see if there are any restrictions or guidelines that you must follow when building your new basement steps. Some areas require a certain slope to basement steps in order for them to be deemed safe. If you don’t follow local building codes and something happens, you could be liable, especially since your home insurance often won’t cover damages if things aren’t built to code.
Step 2 – Get Needed Permits
If a permit is required for this type of construction, don't try to dodge the permit fee just because the stairs will be invisible under your house. Obtaining a permit and following building codes will protect you and your family from both accidents and lawsuits.
Step 3 – Where Are the Stairs?
Determine how much space you have for the stairs and where they will be situated. Depending on local building codes and where you want the stairs to end, you may have to build your basements stairs in an L shape or with a small landing. The easiest option is building the stairs straight down, but that may not be practical in the space allowed.
Step 4 – Take Measurements
Measure the distance starting from your basement floor straight up to the basement ceiling. That will be your total rise. Mark where the stairs will end in the basement. Measure from that mark to the first floor. That will be the total run.
Step 5 - Math
Convert the total rise into inches and divide by 7, which is the riser height. The dividend equals the number of risers you will have in your staircase. If you end up with a number that is not a whole number, round-up.
The number of risers will also give you the number of treads (steps) you need. If your calculation gave you 16 risers, you need 15 treads. Whatever the number of risers, subtract 1 to get your tread number.
Convert the total run from feet to inches and then divide that number by the number of treads to determine the width for your stair treads.
In a typical room, adding together the riser height and tread width should result in 17-18 inches, but since the basement floor may or may not be a standard height from the floor above, be prepared for unusual measurements.
Make sure you don't end up with one step at the top of bottom with an odd height. That will cause a trip hazard. Make all of the risers and treads the same by averaging the measurements across the total length of the stairs.
Step 6 – The Build
Build the staircase as you would any other, but be prepared to work in cramped spaces and answer questions that wouldn't apply to stairs in finished rooms. Each basement is different, so you have to plan ahead and make these determinations for each individual space.