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I am redesigning my entertainment nook. I've taken out all the shelves, sheetrock and most of the framing that was my entertainment nook and fireplace. There is a 10' 4x8 header that spans the opening resting on 2 jack studs on each side that was my entertainment nook and fireplace. I've left a couple of vertical 2x4 in place in the center as I don't want to remove them until I know whether or not I need to add a larger header to support the span.

This is an exterior wall to the house and the entertainment/fireplace nook is a bump out of that exterior wall. This is 2 story house so above this family room space is half master bedroom and half open attic space that I can stand up in. Above the open attic space is the roof.

My guess is that the 10' long 4x8 header over the opening is sufficient to carry the load above and the 2 vertical 2x4s that I've left in the center aren't necessary but wanted to make sure.

I could add another 10' header or support beam under the current 10' header to add more support if necessary. Just trying to find someone who knows this stuff to verify it is sufficient to carry the load before I take out the center 2x4s and continue the remodel of the space. Is there a manufactured product or stronger support than wood header that I could use under the current header to really reinforce supporting that span?

Thank you for any input or guidance.

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  • You say you "left a couple of 2x4 in place". Were these in the original construction or did you add them because you felt they needed to be there? Was there any sag in the original header? If so, how much?
    – FreeMan
    Jan 20, 2022 at 18:08
  • Please edit to add pictures.
    – Ecnerwal
    Jan 20, 2022 at 18:53
  • A double 2x8 header is not sufficient for that span in that location, by modern standards. It's even questionable with a center post. I agree that more details are needed.
    – isherwood
    Jan 20, 2022 at 19:34
  • I left two vertical 2x4s at the center point that were part of the original construction. No, there was no sag in the header, and still is not. The header is not a double 2x8 spanning the 10 opening. It's a 4"x8" header that spans the 10' opening on 2 jack studs on each end. Just wondering if it's enough to span that opening or if i need to add another header or other support? Jan 20, 2022 at 21:39

1 Answer 1

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A 4x8 spanning 10’ will support about 325 to 380 lbs. per linear foot (plf) depending on the species and grade.

If your roof rests on this beam, (no upper floor) then it’s carrying about 25 psf Live Load (snow) plus 10 psf Dead Load Then the maximum roof joists can span onto the beam is:

325 plf / 35 psf = 9.2 ‘ at 12” oc or 7’ at 16” oc or 4.5’ at 24” oc

That means the joists can be 18’ long for 12” oc and 14’ at 16” oc or 9’ long for joists 24” oc (The other half is transferred to the other wall or beam.)

The calculations are similar for floor loads, but the loads are higher and the 4x8 probably would not be adequate.

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  • WOW...that's great information My situation is complicated by the fact that this is a two store home and there is a floor above this family room However, the space directly above this family room is half attic and half bedroom. I think there is a large glue laminated beam that is in the middle of the ceiling above this family room. The bedroom floor and wall rest on this glue lam beam in the middle of the family room ceiling. from that glue lam to exterior wall is attic space above the family room. Jan 20, 2022 at 23:03
  • So, i would assume the floor above is carried on the glue lam that spans the space above my family room and the exterior wall is really only holding up the roof. The 2x4s joists in the attic that make up my family room ceiling leading out to the exterior wall and the nook are 16" on center, i think, but i'd have to check. The roof joists that are above that attic space are 24" on center, i think, again i'd have to check. Either way sounds like i need more header for that span? Can i augment was is there? Add another 4x8 under existing? creating a 4"x16" header?? Jan 20, 2022 at 23:03
  • How far do the roof joists span over onto the 4x8 header and how far do the floor joists span over onto the 4x8 header.
    – Lee Sam
    Jan 21, 2022 at 4:47
  • Wait, @JimPlaskett, you have a 4x8" beam spanning the nook, then an additional glue lam above that supporting the bedroom floor? How thick is the floor between ceiling below and flooring above?!? Or does/did the 4x8" extend down into the living space below, "defining" the edge of the nook?
    – FreeMan
    Jan 21, 2022 at 14:18

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