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Are joist hangers needed

M

Mike F.

Registered User
Joined
May 5, 2019
Messages
10
Location
Massachusetts
I am framing a dropped ceiling below an existing floor assembly which is 3" off level over 20' +/-. The dropped ceiling members are 2x6's with a span of 9' attached to ledgers using 3" screws. Dropped ceiling will only support new 5/8" blue board. Question: are joist hangers needed at each end of the Dropped 2x6's according to IRC regulations
 
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Mike F.,

Welcome to The Building Codes Forum !

What is the length of the ceiling joist that is bearing \ setting
on the ledgers strips ?.........If you do not have a minimum of
1-1/2", then joist hangers are required [ RE: `15 IRC, Section
R606.6.3.1 & Figure R602.7.2 ]........Also, do you have
blocking in between each ceiling joist to prevent rotation ?

The 3" inch screws do not tell us anything......Are they approved
by the AHJ for use in this application, versus nails ?....Screws
can very easily be over-torqued and break off the heads.

9 = 9 = 9 = 9
 
Flexo said:
See R802.6 the ends of ceiling joists shall have not less than 1.5" of bearing on wood or metal.
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R802.6 Bearing. The ends of each rafter or ceiling joist shall have not less than 11/2 inches of bearing on wood or metal and not less than 3 inches on masonry or concrete. The bearing on masonry or concrete shall be direct, or a sill plate of 2-inch minimum nominal thickness shall be provided under the rafter or ceiling joist. The sill plate shall provide a minimum nominal bearing area of 48 square inches.

As soon as I hear the word screws I figure that you are screwed. Maybe it's wrong of me but I immediately wonder what kind of screw. Then you tell me and I wonder if that screw is good enough. I just don't like screws. Unless it's floor sheathing.....then I like screws more than nails.....oh and glue.....don't forget the glue.

The first house that I ever built has roof sheathing that will never come off. LOL I was quite young and had zero experience.... I came to California from Illinois so of course the house was overbuilt. Well I had left over glue soooooo......that's one roof that will never squeak.
 
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north star said:
@ ~ @ ~ @

Mike F.,

Welcome to The Building Codes Forum !

What is the length of the ceiling joist that is bearing \ setting
on the ledgers strips ?.........If you do not have a minimum of
1-1/2", then joist hangers are required [ RE: `15 IRC, Section
R606.6.3.1 & Figure R602.7.2 ]........Also, do you have
blocking in between each ceiling joist to prevent rotation ?

The 3" inch screws do not tell us anything......Are they approved
by the AHJ for use in this application, versus nails ?....Screws
can very easily be over-torqued and break off the heads.

9 = 9 = 9 = 9
Click to expand...
We plan on strapping the entire ceiling with 1x3s. Would that eliminate the need for bracing/blocking? I'm not 100% sure about the screws but they are designated as framing type screws. I looked at figure R602.7.2. In the 2012 IRC that depicts a typical wood structural panel box header const., I'm not sure how this relates to my question? Also, the ledger that we are attaching the ceiling joists to is vertical ( not layed flat ). It is lagged into solid material below the existing floor assembly. So, either we just toe screw the ceiling joists or add the hangers.
 
The joist are 9' long. Even if you used drywall screws it's not going to fail. But then you didn't ask that question.....you asked what the code requires. There's a whole 'nuther code section for the lags.
 
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Mike F. said:
We plan on strapping the entire ceiling with 1x3s. Would that eliminate the need for bracing/blocking? I'm not 100% sure about the screws but they are designated as framing type screws. I looked at figure R602.7.2. In the 2012 IRC that depicts a typical wood structural panel box header const., I'm not sure how this relates to my question? Also, the ledger that we are attaching the ceiling joists to is vertical ( not layed flat ). It is lagged into solid material below the existing floor assembly. So, either we just toe screw the ceiling joists or add the hangers.
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I failed to mention that this is inside a brick and mortar, three condominium unit built in the 1830's, in the Beacon Hill area of Boston. So, this is by no means conventional framing. Think type IV construction ( heavy timber ). We are just trying too level off the ceilings.
 
Mike F. said:
I failed to mention that this is inside a brick and mortar, three condominium unit built in the 1830's, in the Beacon Hill area of Boston. So, this is by no means conventional framing. Think type IV construction ( heavy timber ). We are just trying too level off the ceilings.
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I understand you are working in a building that does not have conventional framing but your framing will be conventional so it needs to comply with the minimum code standards. You will need joist hangars if you are not bearing on 1-1/2" of wood or 2" of masonry. This is a typical setup to level a ceiling and common to see joist hangars nailed in place.

Why don't you do it in lightweight metal studs? Wood is overrated and more work.
 
Jeff and ICE. Think outside the box. How is the proposed design different from a top cord mounted floor truss?
No hangers required on the lower "cord".
typical-top-chord-bearing.png
 
Given the nature of the existing building I do not believe that the IRC should be used. It was not intended for such situations.

I suggest that you either look to the existing building code or the regular building code. With these codes there are provisions for calculating the strengths of screws. An engineer should be able to evaluate the capacity of the connections and if necessary propose a fix.

On the other hand it might be easier to remove the screws and install joist hangers and keep everybody happy.
 
Mark K said:
Given the nature of the existing building I do not believe that the IRC should be used. It was not intended for such situations.

I suggest that you either look to the existing building code or the regular building code. With these codes there are provisions for calculating the strengths of screws. An engineer should be able to evaluate the capacity of the connections and if necessary propose a fix.

On the other hand it might be easier to remove the screws and install joist hangers and keep everybody happy.
Click to expand...
F76PDxX4
 
Mike F. said:
F76PDxX4
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I would also like to see what type of fire separation or fire resistance level we would need to apply considering that it is a separate condominium above. The building itself contains a total of three condominiums, does this become commercial or residential code?
 
Mark K said:
Given the nature of the existing building I do not believe that the IRC should be used. It was not intended for such situations.

I suggest that you either look to the existing building code or the regular building code. With these codes there are provisions for calculating the strengths of screws. An engineer should be able to evaluate the capacity of the connections and if necessary propose a fix.

On the other hand it might be easier to remove the screws and install joist hangers and keep everybody happy.
Click to expand...

I would be more than happy to accept a stamped set of engineered drawings or a letter confirming the installation with screws would work in lieu of joist hangars.
 
Mike F. said:
I would also like to see what type of fire separation or fire resistance level we would need to apply considering that it is a separate condominium above. The building itself contains a total of three condominiums, does this become commercial or residential code?
Click to expand...


So is this a complete remodel of the building or just one existing unit???

And if comolete remodel what was the building before???
 
Nine feet of 2"x6" is hardly worth the internet space that this has occupied. A hundred hangers vs. an engineered design? Well perhaps you have an engineer on staff. My wife has an IT guy that's not busy enough so he gets simple jobs too.
 
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It's possible a 2x2 ledger could be placed under the 2x6 CJ's if crown moulding is to be used to cover up the 2x2? The 2x2 ledger would also give you something to nail your crown moulding too. Other than that I enforce a 1.5-inch bearing as others have indicated.
 
Pcinspector1 said:
It's possible a 2x2 ledger could be placed under the 2x6 CJ's if crown moulding is to be used to cover up the 2x2? The 2x2 ledger would also give you something to nail your crown moulding too. Other than that I enforce a 1.5-inch bearing as others have indicated.
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The ends of the joists could be notched at the ledger to make the ceiling flush. Joist hangers might be simpler, although I agree they are overkill.

I'm not sure that code requirements for ceiling joists would apply. "Ceiling joists" implies attic space above with potential storage load. This is more like a very wide drop soffit.
 
Forget wood, use a suspended metal ceiling grid, check the USGS or other metal gimpson(sp) sites for details. Sounds like if brick all around the permiter no fire blocking needed, if not sheetrock the walls first to the existing top plate then install grid
 
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