[motoriderx7x]

Just have some questions about framing in for new stairs to the basement and cutting the hole in the existing floor.



Attached is the framing I'm going to do around the hole after it's cut to put new stairs in. Pardon my horrible MS paint skills

Original joists are 2x6 rough dimensional lumber.

The length of the cut is about 11'6". No cuts have been made yet, and I have a temporary support in place using a 4x4 horizontally under the soon to be cut joists and floor jacks . I'll be cutting away the joist that run across where the stairs will go. From the attachment you can see the joists connect over top of the exterior block wall in the basement. As I understand it normally you would double up on the non cut joists on the to ends and use doubled up boards with hangers to join to the newly double'd up full length joists.

Questions:
1. If I'm using a 2x4 wall to support a double 2x10 header that I will nail the cut joists to using hangers. Do I still need to double up on joists that were not cut on either end? Or am I completely wrong and should re-think this?

2. I'm using plastic sheeting, tuck tape, rigid foam board for insulation and furring strips screwed in to the block with masonry screws (counter sunk into the strips). I plan to use a 2x4 to space the stringers away from the fur strips to leave a gap for drywall and a skirt board. Are the furring strips sufficient to screw the 2x4 and eventually nail the stringer to (the stringer will be properly set in at the hangerboard and bottom?

3. The bottom plate of the framed support wall should be pressure treated lumber correct? I have concrete unfinished floors in the basement. I am assuming the same will go for the board I anchor the bottom of the stairs to?

As always any help is greatly appreciated.

 

[ront02769]

Bottom plate pt for sure. If the top joist in Your pix is sitting on. Block, no need to double it. If the header is sitting totally on a supporting wall, no worries. As to the bottom joist, extend the support wall for another inch and a half to get that also and no need to double that. Also, no need for two bye ten header, two bye six will be just fine.....since that too is sitting on a wall. Basically, you are doing the same thing at that point that the end wall of your house does, holding up those jpists. Ron

 

[carpdad]

Double header is better for nailing-more meat so the nail doesn't stick out. Posts (dry) with base anchors under the joist-header joints. Make sure you have enough room for all the finish materials and handrail. If the stairs is the only entrance/exit, use 36" door if you have the space. And when making space for the stairs, you need more room on the bottom tread side for a headroom-min. one joist bay for not feeling like youre walking into the wall. But if not, I think the rule is door opening (6'8") height from the nose to the ceiling. Check this, basement rule may allow less.
There should be a overhead light (recessed) for the stairs and the light switch before the door. Boiler shut off switch is usually around there, protected from accidental touching.