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Ledgers, Ledger Strips and Ribbon Strips.

Mr. Inspector

Mr. Inspector

SAWHORSE
Joined
Nov 28, 2009
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Poconos/eastern PA
Not sure what the diffance is.
IRC 2018 Not in any earthquake or high wind area.
R502.6 Lets you support the ends of joists on a 1x4 ribbon strip when nailed to the studs and the joists are nailed to adjoining stud.

1. The code seems require only a 1x4 ribbon strip, nothing else. It does not say if this is a minimum or maximum size.. Can you go larger like a 2x4 ribbon strip?

2. In Table R602.3(1) Fasting Schedule I cannot find anything about how to fasten ribbon strips to studs' and the joists to the studs. Would this need to be engineered?

3. Is there a way that I can nail a ledger to the studs and and support the joists on top of the ledger, R502.6 does not say I can support joists on ledgers. Would I have to use joist hangers on the ledger to comply?

4. Would the ledger in #3 be called a "ledger strip" in Table R602.3(1) Fasting Schedule?

5. Besides the deck section does the IRC allow ledgers at all?
 
No. 1 comes from balloon framing, where studs run from foundation to top plate supporting rafters. Both old houses I lived in the top plate was a foot or so above attic floor, so both second floor joists and attic joist rested on 1x4 ribbon strips. The 1x4s were let into the rough sawn 2 x 4 x 20' studs, probably a couple 8 penny nails. I don't know what nailing was used for joists to studs.

I've been tempted to build this way but I'd guess not but a handful of houses in US are each year. The IRC basically allows what was a common method up until very early 1900s?

I'll leave more modern framing using ledgers to younger folk.
 
In my opinion, a ledger strip is nailed to side of a beam, like a 2x2 at bottom of an 8x12, to support 2x10 joists, which are toe nailed to beam. It's an option to joist hangers.

A ribbon strip is let into studs, and the joists sit on top and continue into the wall past the face of the studs.

But don't rely on my interpretation, based on observation and reading, too heavily.
 
1) The first sentence of R502.6 calls for 1-1/2" of bearing for joists bearing on wood or metal, or the use of an approved joist hanger. The second sentence offers a 1x4 ribbon strip (only 3/4" of bearing) as an alternative if each joist is also face nailed to the side of a stud. So if you go up to a 2x4 strip, that's fine bearing-wise, it complies with the first sentence.

2) Good question; see (4) below. The word ribbon does not appear anywhere else in IRC Chapters 1-6.

3) A 2x ledger would comply with R502.6 because it provides 1-1/2" of bearing (assuming full length joists).

4) The only references in Chapters 1-6 to "ledger strip" are R502.6.2 and line 28 of Table R602.3(1). However, it strikes me as reasonable to use that nailing specification for a ledger as well, since the loading is very similar. Note also the requirements of R02.7, which would either require the joists to be face nailed to the side of a stud, or full depth blocking between joists.

5) See (3) above.

Cheers, Wayne
 
In simple terms... this is what each looks like. Note that a ribbon board is let-in to the stud and joists are face nailed to the balloon framing. Whereas a ledger board is face-anchored (face-nail is not always permissible; subject to withdrawal) to either the rim joist or stud framing. As others have pointed out, requirements for minimum bearing area are different - ribbon board providing 0.75" plus face nailing within wall cavity and a ledger typically using joist hangers, but can be installed below joist and provide 1.5" bearing.

Ribbon board​
Ledger board​
R.d6557dba73d93b948ab9d9a87497013b
R.9d017ac26f031785d13b87765a4cd942
 
I'd be hesitant to make a ribbon board wider than 1" nominal if the studs are 2 x 4. A 2 x 4 ribbon would be OK with 2 x 6 studs.

The load on the joists is partly carried by the ribbon and partly by the nails into the studs. However, Table R602.3(1) doesn't give the number or size for the nails.

The main advantage of balloon framing is that there is less shrinkage. This mostly occurs at the floor lines of platform framing, and could become significant in upper stories with masonry veneer. R302.11 requires fireblocking at floor lines. Another reason balloon framing is rarely used anymore is the difficulty of finding affordable 20 foot or longer studs.
 
Ledger strips and ribbon strips, whether let in or face nailed are seldom utilized. Let in is more work and face applied strips result in a finishing problem. The most common is a ledger and joist hangers.
 
OK then. Is there anything about using a leger besides for a deck in the IRC?
I'm asking because I went to an inspection where they are building an addition with a shed roof. The rafters and ceiling joists were attached to legers that were attached to the existing studs. The inspector before me failed it and said to bolt the leger to the studs. I asked the other inspector where that was in the code and he could not answer me. So I tried to find it in the code and found these leger strips and ribbon strips with no definition in the code or dictionary.
 
I wish there was a picture but it sounds like a 2x4 or close anchored to face of studs and joists just sitting on it. I believe this is not a good connection and do not recommend it. Even if joists extended into wall and nailed to studs, weaker than a ribbon strip. Lag screws or similar would be better but the eccentric load on the studs has problems IMHO. To likely to roll and withdraw.
 
Rick, is it a rafter framed roof? If so, the outward thrust of the rafters is unlikely to be properly resisted via the ceiling joists given the attachment method suggested (hangers and ledger). Definitely would require some type of engineering design or a raised rafter tie.
 
I agree with classic T. All of gravity load is on fasteners and reason to believe there is withdrawal force as well. How is ledger attached to studs?
 
bill1952 said:
I agree with classic T. All of gravity load is on fasteners and reason to believe there is withdrawal force as well. How is ledger attached to studs?
Click to expand...


Ledger was just nailed before when the previous inspector failed it and said to use bolts. When I went I saw bolts but I don't know if it complies to code.
 
classicT said:
That must mean that the wall extends above the roof for a parapet then?
Click to expand...
Not necessarily a parapet. The wall could extend upward to a separate roof plane. E.g. a 1 story addition on a 2 story exterior wall.

Going back to the ledger strip analogy, if floor joists frame into the side of a taller girder, and are supported on a 2x2 ledger strip with the prescribed nailing frequency, is there any prescribed nailing from the joist directly into the girder?

If not, then the prescribed ledger strip nailing is deemed sufficient to carry each joist. The required load transfer from the ledger in the OP to the stud wall would be identical. So to me it would follow that the prescribed ledger strip nailing frequency would suffice for the ledger to stud wall connection, as long as the rafter loading is not more than joist loading would be.

Cheers, Wayne
 
It's no. 21 in table R602.3(1). 3 or 4 toe nails. I've never seen s joist on a ledger strip not toenailed to girder.

Ledger strips are no. 28. 3 or 4 nails at each joist.

I say ledgers, as seem more common in decks, are different and separate from ledger strips.
 
bill1952 said:
It's no. 21 in table R602.3(1). 3 or 4 toe nails. I've never seen s joist on a ledger strip not toenailed to girder.
Click to expand...
Ah, thank you. That says "Joist to sill, top plate, or girder" so I was thinking of only top bearing on the girder. But there's no language limiting it to top bearing for the case of a girder, so it would apply to joists framing into the side of the girder.

So now for the case of a ledger strip, and 0.131" diameter nails, we have 3 toe nails joist to girder, and 4 face nails ledger strip to girder. No nails joist to ledger strip?

bill1952 said:
I say ledgers, as seem more common in decks, are different and separate from ledger strips.
Click to expand...
OK, but is there anything in the IRC that would prohibit the use of a ledger as described by the OP? Absent any direct specification in Table R602.3(1) for ledgers, that leaves consideration of a ledger strip, or of a deck ledger bolted connection, as the available analogues.

Cheers, Wayne
 
Ledgers supporting decks are subject to continuous wetting, which reduces lumber strength by 10% or so, and leads to nails getting rusted, especially with the newer preservative treatments for wood. Bolts are also better in resisting lateral loads.

The way I've often seen flush beams sometimes built is similar to bill 1952's post #8, except that the ledger is a 2 x 2, and the joists are the same depth as the beam and notched at the ledger.
 
wwhitney - I think that entry to the table was probably written long ago, when it was more likely the carpenters knew what to do. I don't really like the ledger strip concept. There's a JLC article with test that clearly shows not as structurally sound as a joist hanger. I can't say it's not structurally sufficient. The JLC application was decks iirc.

Not sure at all but seems ledger strips are permitted for floors, and I would say not decks.

But guessing because it's not clear.
 
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