There are a lot of poor quality contractors and carpenters out there, when people sign up for having handrails system installed on a stairway. They are surprised as to what was built. A Lot of contractors build a knee-wall 2”-3” above the tread, covered by a wood trim board and then the handrail system on top the trim board, because they don’t know how to install a exposed tread system.
A cheap exposed tread system looks like this photo. What makes it look cheap is the skirt board. The reason is that it does not match the baseboard joining up with it.
If you have to put in an inexpensive knee wall over a handrail this is a quiet but elegant way of going about it.
If you have a smart carpenter use a 1”x 8” board and a piece of 5” tall base to make a custom make skirt board. Join them to together with a biscuit jointer and glue. Than run it through a surface planer and bring them down to the same thickness. A few minutes of light sanding, and your new skirt board is ready to be custom cut.
Not only can it be custom cut into the base, but you can make it follow up the staircase to the 2nd floor enhancing the look of staircase.
The question is; Can the stairway hold it’s own weight as well as the working load being put on it.
Osha requirements for a stairway;
From a design standpoint, the specified design loads (e.g., normal live load and moving concentrated load of 1000 lbs.) must be placed where the maximum stress is experienced by the individual structural components of the stair system.
Looking at a framing section of a stairway the sawtooth cut boards are called stair jacks. Looking closer at a jack the deepest cut of the notch for the step into the jack to the bottom side of a jack if your using a 2” x 12” will be 3 1/2” to 4” of uncut material is equal to a 2” x 4” with this understanding we can calculate out what a 2” x 12” stair jack system can carry. With all lumber we do not measure the length of the steps from the top to the bottom but instead from the front edge of the step to the load bearing point that supports the top of the step. A wall height of 8’ and a floor joist of 9 1/2” will make the run of the stairjack 12’5”.
A single 2”x 4” spanning 10’2” can only carry 10 Lbs. per running foot times 3 jacks a total of 300 Lbs. Nailing a 2×4 on the side of the jack doubles the working load to 600 Lbs. But on the problem above we are short 2 1/2 feet. Going to a 2” x 14” stairjack will leave a 2” x 6” amount of material left this will carry a 20 Lbs. 12’9”
With 3 Jacks the total dead and live load for this stairway is now 12.75 x 20 x 3 jacks= 765Lbs. adding 3- 2” x 6” on one side of the Jack doubles the load 1530 Lbs. This is now a legal working stairway for wood steps.
The problem now comes in when the homeowners want stone on the treads and risers. The weight alone is 32 Lbs. per SF or 1153.1 Lbs. for this stairway. And it only leaves 377 Lbs. for live load. Changing and using a LVL or a micro laminated beam works much better. Using a 1 3/4” x 14” LVL beam with a 12’9” span will carry 68 per SF. X 3 Jack you a total working load of 2601 Lbs. this passes with flying colors. This gives you a live load of 1448 Lbs. Or in other words, you can have 6 adults sitting or standing on the stairway for a group photo and it will not wince.