We are replacing the exterior steps to our basement entry (8' concrete stairwell). The previous stairs were supported by three 2x10 stringers for a 4' wide tread. The 2 side stringers screwed to the sides of the stairwell AND into a ledger at the top with hangers along with the center stringer. Mid way up the stairs, there was also a support structure of 4x4 posts holding up the stringers.
1. Do I need to have the side stringers connected to the sidewalls, or can they just hang off the ledger at the top? i.e. the ledger connection should be all the strength they need? Maybe tapconing them to the sides just gave them lateral stability?
2. Do I need the mid-support structure that was there before? I assume three stringers for a 7-8 foot total rise should be fine with just the ledger connection?
3. Would I consider using 2x12s instead of 2x10s?
4. Can I get pre-cut stringers or is are those for when you have a little more flexibility on the rise and run and location of the bottom tread.
What I meant in Question 2, was do I need support underneath the stringers midway up the stairs. There was a structure of double 2x4s that were used to hold stringers up mid way up the stairs. I guess to support the middle stringer that wasn't connected to the wall.
Also, if I attach the side stringers to the concrete wall, can I use tapcons? For a 10' long stringer would I have 2 tapcons every 2 feet or so?This message has been edited. Last edited by: kal72,
If your old stringers were made from 2x10's, then that was the reason for the central support. If you make that center stringer out of 2x12, then you will not need the center support.
TapCons will work fine for attaching the two side stringers to the walls. I'd do a minimum of one under each step.
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