Joist Hangers at Cantilevered Rim

It occurs to me that joist hangers that are installed at a cantilevered rim joist should either be installed “upside down”, or should be replaced by a different piece of hardware. I can’t find anything that addresses this type of installation on the Simpson website. Does anyone care to share their thoughts on the subject?

This particular joist hanger is a double sheer design, but the installer used 1.5" nails that don’t even pentrate into the rim joist. Oops.

On cantilevered floor joists with double rim joists, I always installed the joist hangers upside down. It wasn’t such a big deal with a single rim joist and 2x6 wall above.

This is a deck application, and the guardrail is bolted to the rim joist. The rail felt fairly solid in spite of the improper fasteners, though I don’t like the gaps between the joists and the joist hanger cradles.

The pic you posted looks fine and it is kind of hard to tell from Michigan but you can recommend adding fasteners if you think they’re needed.

I talked to the engineers at Simpson and they say their hangers have been tested and can be used upside down as long as a private engineer has calculated the design loads for the specific job at hand.

I do not see the need for any of those joist hangers right side up or upside down.

Band/Rim Joist: Band joists, also sometimes called rim joists, are just joists at either the side or end of the deck. There’s nothing special about them. In fact, unless you’ve got stairs attached to one of them, band/rim joists only have to carry a fraction of the load that the regular floor joists do.

The rim joist is also referred to as part of the band joists. The band joists are the ledger, header and rim (side) joists as a whole.

The rim joist is often the member that the railing posts are attached to for support. You will need to give extra support to the rim joist at these junctions. By installing bridging next to an inset post or behind an outset post you will ad a great deal of strength to the bottom of the rim joist. This will keep the railing firm.
You should be securing the rim joist at each end. It will not be possible to use a joist hanger at this connection. You should be nailing your frame together with 16 penny hot dip galvanized nails. Each end of your rim joist should have at least 5 nails. Most builders screw a 6” inside corner bracket inside the frame. This should keep the rim joist from loosening away from the frame.
When it comes to installing the rail post, addittional bridging and reiforcement will be required to help the band joist support it.

[size=2]Marcel :slight_smile: :slight_smile: [/size]

If the cantelever is installed correctly, only 1/3 of the span will be in the cantelever, the rest will be toward the interior. The interior portion of the joists is more likely to carry a heavy load.
If someone happened to place a waterbed on those joists, so that it rested on the joists but it didn’t quite bear on the framing member to which the joists were nailed…and it was directly above your bed… which way would you like to see those hangers installed?

But as to making a call… As Barry said, shouldn’t make much difference as long as all the nail holes are filled with the proper fasteners (cometimes hard to confirm).

Kenton, correct me if I am wrong, but I am looking at this as a porch deck cantilever with no mention of any saunas or even less a water bed.

I am assuming due to a small picture or the whole picture only seen in the eyes of the beholder, that the cantilever is 2’ or less and has a typical rail post attachment.
This picture seems to indicate a bolt through the band joist that I assume is the rail post and has not been reinforce to withstand the lateral pressures that may be exerted on them and the rotation may cause failure even with this inappropriate hanger.

If this is indeed a exterior deck, than the band/rim joist would only be an aesthetics and provide a closure at the end of the deck joist.

I might be looking at this all wrong, I am not sure but feel free to let me know.

Marcel :slight_smile:

Those hangars are not supporting the cantilevered rim joist, they are fastened to one(and are installed correctly). I would be more concerned with how many joist are cantilevered and by how far they extend outside of the structure. How big is the deck? Do you have any full photos?

This may help to clear up some of the previous information posted.

Here’s the joist hangers at a cantilevered section of deck/carport I questioned Simpson about.


Just about everything you said in your last post was correct. It is a short cantilever, and the rail post is bolted to the rim joist. There is no additional framing to support the rail posts.

For those of you who believe that the hangers are installed correctly, I don’t think you have wrapped your mind around where the forces are exerted on a cantilevered rim. The joist is not hung off the rim, the rim is hung off the joist. The joist saddle would therefore need to be at the top of the joist for it to do any good. Also, it is important to use 3" nails (either 10D common or 16D sinker, see pic) in a double sheer hanger for the angled nails. The 1.5" nails that were used (confirmed visually at the inspection) do not penetrate into the rim joist at all! This installation maybe has about 20% of the strength it would have if installed correctly. Is it enough? Like I said, the rail felt firm but I don’t like the way in looks.


Ooops! You’re right Marcel, my bad. We’re looking at the exterior rim joist for an exteror deck… part of the cantelever. Bolting the handrail post to the rim like that will definitely loosen it over time. Quality issue rather than defect the way I see it. Poor design, mostly.

I agree Paul, although if it were a structural cantelever it would be a lot greater concern. On a deck though, I think the poor handrail post connection design will be more of a problem.

The IRC requires that the ends of all joist bear a minimum of 1 1/2" of lumber or be fastened using approved joist hangers.

It is Code violation to not have joist hangers at the ends of joists where they butt against a rim joist.


Bottom line, good catch and call; but you knew that.


There is no reason to have the joist hangers placed upside down in this location because this is not the point of uplift that needs to be resisted.

The point of uplift is on the opposite end of the joist where it either connects to the ledge or at its end where it terminates if ‘sistered’ to another joist.

You are right that in the case of a cantilever, it is the joists that caryy the rim and not vice versa, but a joist hanger is still required at this point in the orientation as shown in oder the keep the rim board from collapsing uder the weight of loads placed down vertically on top of it.

The joist hangers are properly oriented in the photo, and to place them upside down or to not use them at all would be a Code violation.

Only unless a structural eneginner says other wise can the orientation of a joist hanger be inverted as is being suggested.

That’s right, and there should be some means of preventing this uplift that would be caused by a concentrated load at the cantilevered end of the joist. But this is not the discussion topic.

Loads place vertically on top of the rim board will be resisted only by the joist hanger nails. They will not be resisted by the joist hanger saddle unless the joist hanger is installed upside down

That may be true, but inverting a joist hanger is illegal and a code violation under ALL circumstances, as has already been pointed out by someone who referred to Simpson’s own installation instructions, unless it is done under the direction of a structural engineer and as part of a stamped design.

What you are suggesting for the rim-to-joist-connection of this deck is a Code Violation and can only be legally done if it has been designed by an engineer…:shock:

While the use of these ‘upside down’ joist hangers can be used to resist uplift when designed by an engineer, located as they are in the locations they are creates a code violation since they no longer provide minimum bearing for the floor joists at the girder connection.: