A reader's Stairs question: Fixing newel posts?

Neil H.   from   Watford, UK   had this fixing newel posts question.

Hello, thanks for creating a great site. I have been looking at how to fix bottom newel posts to give a rock solid newel and cannot see a definitive answer to fixing the bottom newel when you have a concrete floor.
Obviously the best fixing would be to lap it over an existing floor joist but if you have a concrete floor obviously there isnt one.
In the case of concrete floors is it just a case of morticing out the newel around the string and adjacent stair parts.... would you include a locating pin anchored in the concrete/bottom of newel for extra rigidity in the lateral planes? Any help would be appreciated. Many thanks

Bill's reply

Hi Neil, You are right in wanting to get a solid fix, as a bottom newel takes a lot of force when people swing off them.

• If you have a bottom riser trenched into the newel that should be very stiff. Plus the standard newel to string joint makes it stiff the other way, especially if you can get glue blocks between riser and newel as well,
• Still what with wear and tear, shrinkage, etc.etc. things loosen up over time, and you are spot on in thinking that the bottom must be fixed to the concrete.
• When I do steel stairs, even though they are fully welded at the top, the bottom is either bolted or cast in-situ to the slab.
• There is a good reason for this. If it is not fixed at the bottom, but just sitting there then the will be vibration and movement, however slight this movement will be noticeable and the stair will not "feel right".
• At the newel bolt a steel bracket to the concrete floor and screw it into the newel. This will be hidden by the riser. It will be hard to get at to fix, but it will add stiffness and a solid feeling to the bottom.
• If you have open treads, then put a steel dowel, say 16mm dia. say 75 into the newel (and a 12mm one into the string as well if it is possible) and say min. 50 into the concrete.
• Over drill the hole(s) in the concrete to give you tolerance, fill them with epoxy and then drop the stair into position.
• Then fix the wall string. Bolt it (or screw fix) to the wall top, middle and as low down as you can get.

Best of luck with it.