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Old 09-11-2010, 01:39 PM   #1
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Please help me determine if these are collar ties


Hey guys, I have a question about certain wood members in my attic. The house was built in 1962, I live in New Jersey. The attic is a typical one, the floor joists are 2X8's running in the same direction as the roof rafters which are also 2X8's. The joists span in from the outside wall to the center load bearing wall (it's about 30' in distance across the house so they had to use two joists and stagger them on the main wall in the house).

The peak of the roof is 9' off of the joists, but what I assume are the collar ties are about 4.5' off of the joists. They are made up of some type of sheathing about 8" wide. Many of them are bowed.

I've done a lot of research and found that the collar ties should be in the upper third of the attic. Mine are right in the middle and it's making the attic unusable.

My question is: What are these?? If they are collar ties then I could simply move them up and everything would be safe, I would use 2X4's instead of the crappy bowed sheathing. But since they are right at the middle I have a feeling that they are there to help support the roof and moving them up might take that support away. Is that possible?

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Old 09-11-2010, 02:16 PM   #2
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Please help me determine if these are collar ties


Sounds logical that they were meant to be collar ties, but were mis-installed..

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Old 09-11-2010, 02:27 PM   #3
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Please help me determine if these are collar ties


Seems reasonable. Then again, you're in potential snowload country. An hour of structural engineer consultation time will keep you legal and safe.
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Old 09-11-2010, 03:17 PM   #4
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Please help me determine if these are collar ties


If they are flimsy and bowing, I doubt they are structural without being sturdy and bolted. A picture would help as 2x8 rafters will span 14'10" with no snow load. They may have been installed to gain strength if the rafters are under-sized for your span/area. Proof is in the picture.
Adding Collar Ties to make a ceiling

More reading for you....

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Old 09-11-2010, 04:17 PM   #5
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Please help me determine if these are collar ties


The ridge is 9' and the building is 30' so if my math is correct that would make the rafter length at least 17.5', and we get snow around here...
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Old 09-11-2010, 06:18 PM   #6
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Please help me determine if these are collar ties


Your rafters are clearly overspanned for your snow condition. The elements you describe sound like they were meant to be collar ties, but have probably never functioned in any sort of structural manner. Bear in mind that the purpose of collar ties is to distribute uplift load on the roof due to wind relatively evenly across the roof.

Collar ties ARE NOT substitutes for rafter ties. In your case, the rafter tie function is provided by the floor joists. You can certainly move the collar ties into the top third of the ceiling, however that will not correct the overspan problem with the rafters. To correct that would require structural improvement to the rafters, either replacing them with bigger rafters, or sistering another rafter to each one, or installing roof trusses. Collar ties are not intended to strengthen undersized rafters.
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Old 09-11-2010, 06:36 PM   #7
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Please help me determine if these are collar ties


One thing I forgot is that I have 2X4's running vertical from the joists up to the rafters on both sides where the roof gets low. These are only about 3' high so I doubt they give much support to the roof.
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Old 09-11-2010, 08:02 PM   #8
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Please help me determine if these are collar ties


The may be over-spanned or not. Depends on the following answers.

1. Span= 30'/2 =15' minus the outside wall.... 2x6 or 2x4?

2. Rafters are 24" or 16" on center?

3. Species of wood on the rafter side stamped in ink?

4. Where is your location for snow load calculations?

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Old 09-11-2010, 08:08 PM   #9
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Please help me determine if these are collar ties


Quote:
Originally Posted by GBR in WA View Post
When was the last time you cleaned your dryer ducting?
DIY, don't be a dryer-fire statistic.
Check it this weekend.
Thank you.

Gary, thanks for your signature line about cleaning your drier duct.... that fell off our to-do list in this "new" old house we moved into. I already pulled out the shopvac to remind me to get on it tomorrow.

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Old 09-11-2010, 08:32 PM   #10
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Please help me determine if these are collar ties


Lock, don't know if you'll get anything out of this but we're doing something similar. Take what you can.

Our place is basically the same as yours except in the front of the house there is one long bedroom across the whole space. It used to be two small rooms with that load bearing wall holding up the overlapping joists only years ago someone removed the wall and put nothing in its place. The joists are sagging, and the plaster will fail one of these years, and we don't use that space right now. Worse, a massive snow load could push the walls apart and drop the roof, since the rafter ties aren't functioning as designed in their sagged and torqued condition. (Our engineer said at first glance, "now THERE'S a problem.")

We've braced the ceiling already on both sides of where the wall used to be; when we're ready we'll drop the ceiling across the span, add some temporary cables to act as temporary rafter ties so we can cut the joists apart, then we'll cut a gap in the joists for a partially hidden beam, and then hang the joists either side of the beam with hangers.

We'll also sister the joists with larger ones, to allow attic conversion later. (We have the headroom on the 2nd story to give up a few inches, but none in the attic, so the new material will hang down. That means the attic floor will remain flat.

Last, as we finish it all off, we'll do any tweaks we need to do so if we wish later on it will be easy to add a "moveable wall" if our space needs change. If we do that down the road, the idea would be to split the rooms or combine them without major remodeling as our needs change, but still have either arrangement code compliant.

Have fun
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Old 09-11-2010, 08:41 PM   #11
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Please help me determine if these are collar ties


Quote:
Originally Posted by GBR in WA View Post
The may be over-spanned or not. Depends on the following answers.

1. Span= 30'/2 =15' minus the outside wall.... 2x6 or 2x4?
I'm not really following what you mean here about 30'/2=15'. The walls are all 2X4".

Quote:
2. Rafters are 24" or 16" on center?
2X8" 16" OC
Quote:
3. Species of wood on the rafter side stamped in ink?
Not sure, i won't be over there for a few days.
Quote:
4. Where is your location for snow load calculations?
I'm in northern NJ, I am not sure how to find out my snow load.
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Old 09-11-2010, 09:16 PM   #12
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Please help me determine if these are collar ties


1. 30' span divided by 2 = 15' horizontally. Minus the 2x4= 4" = 14'8" span

2. 16" on center spacing increases the rafter span: http://www.awc.org/calculators/span/...orizontal+Span

3. Could be any species, if doug fir/larch as in the calculator, 16" on center will span 16'2" with a 20# snow load.

4. Very important: http://scienceblog.com/community/old...199700290.html
http://www.groundsnowbyzip.com/

It probably got inspected when built but codes (and inspections) were more lenient then....

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Old 09-11-2010, 10:03 PM   #13
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Please help me determine if these are collar ties


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1. 30' span divided by 2 = 15' horizontally. Minus the 2x4= 4" = 14'8" span
Ok, so the span is the length that the rafter covers horizontally? I thought that it would be the total length of the rafter, which is why I said it was around 17.5'. Thanks for clarifying.
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Old 09-12-2010, 02:50 PM   #14
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Please help me determine if these are collar ties


I made a big mistake

I just spoke with my Father who was at the house last and he said that the roof rafters are 2X6's
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Old 09-12-2010, 03:30 PM   #15
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Please help me determine if these are collar ties


i was going to say,i'm sure you must have had some snow on the roof since 62 in nnj

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