Overhang framing question

[69gp]

Hi,

Getting ready to start my garage addition. I do have one question that I need a little clarification on. I have an overhang inside the garage space on the 2nd floor. The overhang is 18" The architect used 14" i-joist to extend the 18". The overhang is not structural but extended to make the walkway a little wider to clear some dormers. I had mentioned that I wanted to use 2x10s as I felt that was all that was needed for the span. This would give me 4" to the garage height below. The the span is 12 over the bay below. My gut feeling is he did not want to do the extra framing details for the height difference. the back of the garage addition is 34' So I can see the 14" depth there. Does anyone have any input if a 2x10 can span the 12' and then overhang 18".

thanks
steve

 

[p_mori7]

Depends on how much weight you want to put up there.

 

[kbs2244]

I would guess he use the 14 inch to have the top level with the floor.

 

[69gp]

Depends on how much weight you want to put up there.

Just an overhang to make the walkway wider. only weight will be a railing

 

[p_mori7]

I get the walkway part (I think)

 

[850xpeps]

I’d venture to guess he did it because you told him you wanted a walkway. Make it a second floor and by code requiring certain specs. That being said my house spans 12’6” with 2x10.


Sent from my iPad using Tapatalk Pro

 

[69gp]

No loads other than maybe some furniture for a sitting area. The overhang is just to get more headroom for access to a couple of dormers. I will try and post a couple more prints for clarification.

 

[69gp]

The one drawing with the blue line represents the wall below. Area to the right is what is overhanging. If I can use 2x10s than I can gain 4" of ceiling height. I would like the most headroom possible below for added garage door mounting.

 

[GMCGarage]

Hi,

Getting ready to start my garage addition. I do have one question that I need a little clarification on. I have an overhang inside the garage space on the 2nd floor. The overhang is 18" The architect used 14" i-joist to extend the 18". The overhang is not structural but extended to make the walkway a little wider to clear some dormers. I had mentioned that I wanted to use 2x10s as I felt that was all that was needed for the span. This would give me 4" to the garage height below. The the span is 12 over the bay below. My gut feeling is he did not want to do the extra framing details for the height difference. the back of the garage addition is 34' So I can see the 14" depth there. Does anyone have any input if a 2x10 can span the 12' and then overhang 18".



thanks
steve

2x10 @ 16oc works structurally.

 

[ishiboo]

Grab the engineering guide for the I-joists you are purchasing and take a look. I-joist overhang design and basic load tables will be called out and easy to read. The I-joists we use around here says you could go down to a 9-1/2" at 16" OC for the span to get you the most height you are looking for.

My guess is he is using a load-bearing table to figure out that cantilever, which is designed to support a full load-bearing wall supporting a roof at the very edge of the cantilever. That would probably require at least 14" I's to get you 18". Due to leverage, the absolute maximum called out in the spec is only 24".

 

[ishiboo]

Oh, wait... so the cantilever also supports the joists for the rest of that area on the righthand side? Then no. I'm actually surprised 14" is deep enough. The span over the garage is not relevant... it's the cantilever that requires the beef.

 

[ard]

The one drawing with the blue line represents the wall below. Area to the right is what is overhanging. If I can use 2x10s than I can gain 4" of ceiling height. I would like the most headroom possible below for added garage door mounting.

How will shallower floor joists give you more space below??

You will need to build all lower walls 4" taller. Make sure you understand how that works.

10" will give you more heads space ABOVE by simply changing those joists.

Finally you really need to as THE engineer or A engineer. NOT random, possibly unqualified people on the Internet (apologies to qualified participants.. )

 

[69gp]

Oh, wait... so the cantilever also supports the joists for the rest of that area on the righthand side? Then no. I'm actually surprised 14" is deep enough. The span over the garage is not relevant... it's the cantilever that requires the beef.

the cantilever does not support any joist. There is a wall under the floor joist that is set back 18" from the edge of the joist.

 

[GMCGarage]

How will shallower floor joists give you more space below??

You will need to build all lower walls 4" taller. Make sure you understand how that works.

10" will give you more heads space ABOVE by simply changing those joists.

Finally you really need to as THE engineer or A engineer. NOT random, possibly unqualified people on the Internet (apologies to qualified participants.. )

I think most understand that the floor elevation would not change.

2x10's are fine if you check the design. An Architect should be able to handle that design.

 

[69gp]

How will shallower floor joists give you more space below??

You will need to build all lower walls 4" taller. Make sure you understand how that works.

10" will give you more heads space ABOVE by simply changing those joists.

Finally you really need to as THE engineer or A engineer. NOT random, possibly unqualified people on the Internet (apologies to qualified participants.. )

The floor on the unfinished level will all be the same height. The back of the garage in the wide open area is 14" deep I joist. If I can use 2x10 towards the front of the garage where I only have a 12' span then I could frame the walls below 4" higher to gain the extra headroom.

 

[ishiboo]

the cantilever does not support any joist. There is a wall under the floor joist that is set back 18" from the edge of the joist.

What is the floor where the walkway/etc. is supported by?

 

[ard]

I can gain 4" of ceiling height. I would like the most headroom possible below for added garage door mounting.

I think most understand that the floor elevation would not change.

No, the CEILING elevation doesnt change when you use 2x10 instead of 2x14. The joists still sit ON the walls below.


Anyway, OP came back and clarified he would ALSO frame 4 inches taller below, increasing the ceiling height to maintain the same floor elevation.

My point for asking was that this might not be 'free'....Do keep in mind this could be a significant cost, for 4 inches- each stud, then whatever sheeting you are putting on the walls. The cost to move past standard framing dimensions can be wasteful.... If you need more space just build it taller! .

 

[GMCGarage]

What is the floor where the walkway/etc. is supported by?

from the picture, it looks like the cantilever. The wall is 18" back.

 

[GMCGarage]

No, the CEILING elevation doesnt change when you use 2x10 instead of 2x14. The joists still sit ON the walls below.


Anyway, OP came back and clarified he would ALSO frame 4 inches taller below, increasing the ceiling height to maintain the same floor elevation.

My point for asking was that this might not be 'free'....Do keep in mind this could be a significant cost, for 4 inches- each stud, then whatever sheeting you are putting on the walls. The cost to move past standard framing dimensions can be wasteful.... If you need more space just build it taller! 9ft, whatever....

In construction floor to floor elevations are set. So if you change a beam or joist size, the clear height gets taller below. No engineer/Architect would dimension a wall height. They would dimesion a floor height, and the framer would subtract the required flooring and joist size.

the first sketch shows that. the 4'-5" at the cantilever is to the top of floor. the wall height is what it is based on the rest of the structure.

The OP has not asked for our help or opinions on the cost, so a moot point.

He asked about 2x10's spanning as shown, and its been answered.

 

[ard]

In construction floor to floor elevations are set. So if you change a beam or joist size, the clear height gets taller below. No engineer/Architect would dimension a wall height. They would dimension a floor height, and the framer would subtract the required flooring and joist size.

the first sketch shows that. the 4'-5" at the cantilever is to the top of floor. the wall height is what it is based on the rest of the structure.

The OP has not asked for our help or opinions on the cost, so a moot point.

He asked about 2x10's spanning as shown, and its been answered.

1. This engineer/architect DID dimension the ceiling height in the first drawing.

2. Just because the OP didnt ask about cost doesnt mean he cannot be advised about possible cost issues.

3. Didnt see any structural engineer in this thread say "OK". Several 'should be OK' and your combo of "its OK" and 'an architect should be able to handle that design'

4. OP what it the maximum span of the joist from outer wall to the wall that supports the overhang? (I didnt see any dimensions, but might have missed that) What is the designed loading? pounds per square foot dead AND live?

5. Also note that whomever engineered that took careful time to ensure the heights across many points in the structure have been considered. Just make sure that moving something here wont screw you elsewhere.

 

[GMCGarage]

1. This engineer/architect DID dimension the ceiling height in the first drawing.

2. Just because the OP didnt ask about cost doesnt mean he cannot be advised about possible cost issues.

3. Didnt see any structural engineer in this thread say "OK". Several 'should be OK' and your combo of "its OK" and 'an architect should be able to handle that design'

4. OP what it the maximum span of the joist from outer wall to the wall that supports the overhang? (I didnt see any dimensions, but might have missed that) What is the designed loading? pounds per square foot dead AND live?

5. Also note that whomever engineered that took careful time to ensure the heights across many points in the structure have been considered. Just make sure that moving something here wont screw you elsewhere.

OP, there you go.

 

[GMCGarage]

1. This engineer/architect DID dimension the ceiling height in the first drawing.

2. Just because the OP didnt ask about cost doesnt mean he cannot be advised about possible cost issues.

3. Didnt see any structural engineer in this thread say "OK". Several 'should be OK' and your combo of "its OK" and 'an architect should be able to handle that design'

4. OP what it the maximum span of the joist from outer wall to the wall that supports the overhang? (I didnt see any dimensions, but might have missed that) What is the designed loading? pounds per square foot dead AND live?

5. Also note that whomever engineered that took careful time to ensure the heights across many points in the structure have been considered. Just make sure that moving something here wont screw you elsewhere.

1. No he or she did not. its dimensioned to the bottom of the joists, no ceiling is called out. Overall height is 14'-4 1/2" from floor to floor. So is the joist and floor 16 7/8". Like I said, who knows what is what with this drawing.

2. OK

3. Ok, I am a structural engineer, does that make it more valid on getting a design question answered on the interwebs?

4. OP said 12'-0", and 18" cantilever. I used normal residential loads since OP said it would not have alot up there.

5. I would bet my next pay check the only engineers that have looked at it are the ones on this forum. Can anyone tell me what the thickness of a 4" lally column is??? Right.

Sometimes you will not be the smartest person on the comment thread.

 

[69gp]

just want to to thank all who commented on my thread.

steve b