Stair header

[eenaef]

I need some help w/ my 1893 building. I live in souther Indiana. We have a building inspector but he really is much help. As long as I follow good building practices and it resembles some sort of code he is good with that.

My building is 20 wide x 100 long. The original floor joist were 2" x 12" x 21' long mortist 6" into brick wall on either side on 12" centers. The stair well going into the basement comprised of an doubled 2" x 12" x 11' header running lengthwise that was keyed (no nails or screws) into the doubled up floor joists.

Through a 100 years of termites and water damage all the fingers and rooted away and I have lost the back 16' of my building floor into the basement. I have now installed a 6" 17.25lb I-beam down the center of the whole building sitting on jack posts every 10'. So my span from the beam to th wall is 10'. I need to completely replace the last 16' of the building using latest building materials (this includes the stairwell).

So here is my questions;

1. What spacing should I use on floor joist I will use 2" x 12" x 10'6". Stay w/ the existing 12" on center or can I go to 16"? I will use 1" toung and groove OSB for floor deck.

2. How do I fabricate header. Are the metal U - brackets acceptable for for a header in a commercial application? Is two 2x12 suffiecient for a 11' header. TAre U brackets acceptable for the floor joists? Note the span from header to I beam is only 6' 6".

[Wgoodrich]

2X8 SPF floor joists will span 12' 3" when 16" on center and rated 40 pound per square foot floor.

3/4" plywood tongue and groove will span the 16" on center with no problem for floor decking.

Where your mortice joints are rotted but reach the beam you may cut the flat to the beam and use joist hangers. Same applies for a header using joist hangers.

A header for a 20' wide building may be spanned carrying a center bearing floor, ceiling, and 20 pound roof snow load can be 4-2x12 board header. That means to span 11' on a building carrying the load discribed in this paragraph will take 4 - 2x12s to make the header or go to an engineered beam.

Hope this helps

Wg

[mdshunk]

Here's a few that fall under 110.3(B):

From the UL White Book: "...box extensions are suitable for extending properly secured flush or surface mounted boxes. One or more extensions may be used."

Since the box is not secured in accordance with 314.23, you cannot use extensions rings in accordance with it's listing.

From the UL White book: "...connectors for use with nonmetallic-sheathed cable are also suitable for use with multi-conductor underground feeder and branch circuit cable... ...connectors which are also suitable for use with service entrance cable, flexible nonmetallic tubing, or flexible cord are so indicated on the device or carton.

At least one set of MC/AC cables appears to enter the box through a 3/4 two screw NM connector or possibly a Tomic type NM connector.

Trying to decode that mess, it looks like they'd clearly need at least 80 cubic inches for all those conductors. They only have about 30 in the deep 4 square, and another 20 in the ring. Adding more rings will solve the cubic inch issue, but will cause a 300.14 violation because the conductors will no longer reach outside the opening.

The duplex MC/AC connectors should be examined. The cable armour has tarnished in such a way that it causes me to believe that it might be type AC cable. Not all duplex connectors were rated for grounding continuity. Type AC cable relies on the connector for grounding continuity, and those duplex connectors should be examined and evaluated for that use.

The corrective action will be time consuming. If it was me, I'd be installing a 12x12x4 knockout box in place of that 4 square silliness. Hang it off a few little pieces of threaded rods, re-do that whole mess (properly securing the MC/AC cables this time), and call it a job well done.