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How exactly is the header fastened to the sill plate in box-on-sill construction using 2x dimensioned lumber?

Box on sill

mr blint
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    Good answer over at https://diy.stackexchange.com/questions/216148/how-are-joists-secured-to-sill#:~:text=1%20Answer&text=The%20floor%20joists%20are%20secured,components%20are%20secured%20in%20place – Micah Montoya Aug 09 '21 at 14:48
  • Where is that drawing from? That's not a "header". – isherwood Aug 10 '21 at 15:06

4 Answers4

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The photo below shows detail of the rim board to the sill plate connection. Note that except for the high seismic activity areas, this connection does not need to be made very strong, as the rim board is essentially weighted down on the sill plate by the joists and flooring. The joists are connected to the rim board through head nailing from the rim board to the joists.

enter image description here

r13
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There should be anchor bolts embedded into the foundation wall.

  • You drill holes through the sill plate that line up with the bolts
  • Drop the sill plate over the bolts
  • Place a washer and nut on each bolt
  • Tighten the nuts down

Then, you hope that the guys placing the anchor bolts didn't manage to line any up with where a joist needs to go.

If there are no anchor bolts, you'd use some sort of concrete anchor like a sleeve anchor, drilling a hole through the sill and into the concrete, placing the anchor through them both, then tightening.

As noted by Lee Sam in the comments, once the joists are installed, the rim joist can be toe-nailed to the sill plate to hold it in place during construction, but it's the overlapping of the wall sheathing from the studs, across the joists and down to the sill plate, nailing according to the schedule in the blueprints (including nails through the sheathing into the sill plate) that holds the whole thing together into a solid, cohesive unit, which is then held to the foundation by the bolts described above.

FreeMan
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    Good answer for sill plates, but OP asking about fastening header to sill plate. – crip659 Aug 09 '21 at 15:15
  • reading comprehension fail. :( – FreeMan Aug 09 '21 at 15:19
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    To finish @FreeMan answer, the “header” as you call it (it’s really a rim joist) is nailed to the exterior wall sheathing AND the sole plate. If the plate isn’t anchored to the concrete wall (as FreeMan explains) then the floor system (including the rim joist) can move away from the concrete wall. In seismic active zones and high wind areas an extra steel holddown will be added near the corners of the building. (Normal nailing from the sheathing to the sole plate will not work because as extra heavy shear loads are applied, the sheathing will “unzip” from the sole plate.) – Lee Sam Aug 09 '21 at 15:43
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    Some carpenters like to toenail the rim joist to the sole plate to keep it aligned until the sheathing can be installed. However, the toenailing is not required by code and is not included in the structural calculations. – Lee Sam Aug 09 '21 at 15:49
  • Thanks, @LeeSam - answer rescued! I've included your comments in the answer to make it more complete. – FreeMan Aug 09 '21 at 15:56
  • I hoped there might be a special strap with three flanges, one that fits on the face of the floor joist, one that fits against the face of the rim joist, and one that gets face-nailed to the 2" edge of the sill plate. – mr blint Aug 09 '21 at 17:39
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    Not that I'm aware of, @mrblint, but that does _not_ mean they don't exist. Check the web sites of construction anchor mfgrs (like Simpson Strong Tie, as an example) to see what they've got available. – FreeMan Aug 09 '21 at 17:54
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You can use strapping to ensure that the walls are firmly attached like this:

Sill Plate Strapping

Something like this is likely required in earthquake and hurricane prone areas. Probably a good idea almost anywhere else since high winds can occur nearly everywhere.

While this drawing shows the straps set in the concrete, I don't see that this is in any way a requirement. You could nail or screw the straps to the concrete after it's poured as well as nail or screw to the sill plate. I don't see any easy way to do it on the inside of the wall although you might get creative.

jwh20
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  • Thanks. If I read the diagram correctly, the straps are installed while the concrete is wet, so that precise placement during the pour is very important? Would it be allowed by code to strap the floor joists to the inside edge of the sill plate instead, since the sill plate is anchored to the foundation wall? Is there a variety of strap that could attach to the joist and then get nailed to the inside edge of the sill plate? – mr blint Aug 09 '21 at 16:18
  • ".... *face-nailed* to the inside edge of the sill plate?" – mr blint Aug 09 '21 at 16:24
  • If the straps were not pre-set into the footing, then obviously your only option is to secure them to the sill place. If you are yet to install the plate, then you could easily wrap the straps around it, otherwise you could just nail or screw the straps to the sill which is bolted to the footing wall. – jwh20 Aug 09 '21 at 16:41
  • @jhw20: Nothing has been poured yet, and nothing built. My question in the comment is whether code-compliant straps for face-nailing floor joist straps to the sill plate exist. It's not clear from your comment whether you were answering that particular question. – mr blint Aug 09 '21 at 17:15
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    Then NOW is the time to discuss what you want with your contractor. If you want to find out if your local code requires such things, you should talk with your local AHJ. But it's acceptable to over-build so you might do this even if not specifically required. – jwh20 Aug 09 '21 at 17:18
  • I am doing so. But my contractor is me, and the ignoramus doesn't know the answer to the questions I'm asking. This is DIY stackexchange after all :-) – mr blint Aug 09 '21 at 17:26
  • In that case purchase the materials you need, put what you want on the drawings for the concrete and framing subs, and ensure they do it. – jwh20 Aug 09 '21 at 17:27
  • @jhw20: Your initial drawing was very helpful. I am simply asking if there's an interior alternative that can face-nail to the sill plate (since I don't have full confidence in my abilities to set the straps into the wet concrete exactly where they need to go). – mr blint Aug 09 '21 at 17:30
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Barring extra measures taken for seismic zones, the wall sheathing makes the primary stabilizing connection there. As was pointed out elsewhere, the immense weight of the structure above the foundation virtually eliminates any chance of movement, but sheathing that's fastened to both the rim joist (not "header") and sill plate tie them together.

isherwood
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