Hi all,
This is my first post and would greatly appreciate your thoughts/input on any of the points raised... apologies it's a little lengthy!
My next project at home is to (if possible!) replace the current 'plank-style' bannister on the stairs & landing with a more traditional handrail/baserail and spindles arrangement.
The house is an early 1970's mid-terrace 3-bed and, as I understand, the staircase is a "housed & wedged" routed/boxed stringer type. I assume in order to limit cost and for ease/speed of installation when the houses were built the stair newel posts were off-set to the side of the stair stringer with the 'plank' handrails simply screwed/nailed to the side of the newels. The top of stairs newel has the stair 'planks' on one side and the landing 'planks' on the other side.
The three newels are all the original, single piece, full 92mm posts and are fitted/fixed as follows :
Bottom newel : Set into the concrete floor.. unsure of depth. Very solid. Timber has twisted a little over time.. (see pic)
Top newel : Bolted (x2) - one bolt to the double joist at top of stair, another bolt (at 90 degrees to the first) to the header joist on the landing. Quite solid. (see pic)
Landing newel : Bolted (x2) - both to the header joist on the landing. Quite solid. (see pic)
My observations on the stair stringer as follows :
- From what I can see, only about 30-40mm of the stringer timber sits on the concrete floor at the bottom.. (see pic)
- The stringer is nailed (x2) to the side of the bottom newel (see pic)
- Unsure how/where the stringer is fixed to the double joist at the top of stairs (see pic) (I haven't disturbed the top part of the under-stairs or ceiling as yet..).
- The stringer is nailed (x2) to the side of the top newel. (see pic).
My thoughts so far are that in order to achieve a decent end result I will have to replace/re-position all three newels so the top and bottom newels are aligned with the stair stringer.. and that :
- The landing newel should be straight-forward..
- The top newel would need to be somewhat 'butchered' to be removed.. I say this as it would have presumably been fitted/bolted before the stairs went in.. (the bolt fitted at 90 degrees in to the landing header/joist is not accessible and covered by the stair stringer at the top). The replacement newel could be fitted with something like a Zipbolt Super UT (screwed into the double joist at the top of the stairs) and aligned with and morticed over the stringer.
- The bottom newel could be sawn-off at floor level.. I was thinking the remaining part set in the concrete could be screwed into at an angle using another Zipbolt Super UT then bent plumb to fix the new re-aligned newel to..
Things I'm not sure about :
- The structural significance of the stringer being nailed to both the top and bottom newels and if this fixing is broken with the newel removal/replacement..? Is it nailed for rotational stability in the stringer for resistance to twisting..?
- The small amount of stringer timber sitting on the concrete at ground floor and if the bottom newel is removed.. again, the significance of the two nails through the stringer into the side of the newel..?!? Would additional support need to be added at the base of the stringer under-stairs..?
- Ditto at the top of the stairs... and any idea on how this type of staircase is ordinarily fixed to the joist at the top stairs in a house of this type from the 70's..?
- The depth of the concrete slab and how deep the bottom newel sits into the concrete.. Discounting the use of any remaining newel in the concrete floor, would the Super UT bolt straight into the concrete with a resin fixing be an option..? Would need about 140mm depth for the UT bolt.. Any other alternatives..?
Apologies again it's a lengthy read..
Many thanks in advance for any thoughts/input/experience you may have..