Attic Collar Tie Change/Removal

Reply

  #1  
Old 10-24-04, 08:22 PM
Member
Thread Starter
Join Date: Oct 2004
Posts: 22
Attic Collar Tie Change/Removal

Hello all, first time poster here. I have a 50 year old Cape Cod style house in which I am looking to turn the top 1/2 story into a master bedroom. The house has a standard "A" style roof framing with 2X6 rafters. There are also 2X6 collar ties going across each rafter around 7 1/2 feet up. The middle portion of the roof is dormered out with significantly less pitch (obviously) than the remained of the roof. For the purpose of being descriptive, I will mention that there are about 19 total rafters going across. The dormered out portion contains 5 of them. Previous to starting the project, the first 7 rafters on each side had collar ties, and only 3 of the 5 in the dormered out section had them. I am looking to make that middle portion of the room where it is dormered a cathedral ceiling with a skylight and ceiling fan.

So..... question is. If I leave the remaining 7 on each side in place and remove the 3 in the middle where there is less pitch, am I taking a major chance of possible structural damage, or should the others in general serve the purpose well enough? Just thought I would mention that I do live in Buffalo, NY and there can be a decent snow load. The three middle ties didn't seem to be doing much and at least 2 of them were pretty bowed in the middle, which leaves me in general thinking that there wasn't too much outward pressure on them. However, I am sure looks can be quite deceiving. If I was to leave them in, it would somewhat ruin the aesthetic plan I was following and I also could't use the fan I had purchased. Looking for general comments (understanding the true best thing to do would be to get a structural engineer to look at it.). I thought I could move them up significantly, but have been reading that they should be about 1/3 from the ceiling and might have little or no affect if higher than that. Any thoughts, anecdotes, suggestions? Appreciate any insight.

Almost forgot, the entire room has four foot kneewalls as well with the exception of the dormered out are.

Paul
 
Sponsored Links
  #2  
Old 10-25-04, 04:05 PM
Member
Join Date: Aug 2004
Location: USA
Posts: 215
At that height, the collar ties aren't doing much to counter the spreading load on the rafters. If the builder thought they did, 50 years ago, he was wrong. At most, they serve to hold the rafters together at the ridge against wind uplift. Also, 2x6 is pretty hefty for a collar tie. That makes me suspicious that the builder may have neglected the rafter ties (ceiling joists), which are the critical structural elements that will make or break your project. Bottom line, better have an engineer look at it before you begin removing any lumber.
 
  #3  
Old 10-25-04, 06:07 PM
Member
Thread Starter
Join Date: Oct 2004
Posts: 22
More Info

Thanks for the feedback. I have been doing some additional research and also wanted to post a little more info. I am wondering the same thing regarding the attic floor joists. If everything was built properly (big assumption), the attic floor joists should prevent the spreading and the ceiling joists / collar ties (not really sure that they are collar ties, as they seem to sit where the ceiling should be mounted) should counter the wind upforce. If that was the case, it is quite possible that I could be fine without the three in the middle shed dormer section. However, all of those would be assumptions and would hate to come home from work with a collapsed roof. Your point about the 2X6's is well taken, however, not knowing what the deal was 50 years ago, who knows why they were selected?
My only thought is that at the height you mention, the house has been around 50 years and there are no rafter sags, or any other (obvious) structural damage. I know the attic floor joists are heavy duty as I had to get in the floor to run some heat ducts. Going to see if I can get a contractor friend to come over and take a peak.
 
  #4  
Old 10-26-04, 03:41 PM
Member
Join Date: Aug 2004
Location: USA
Posts: 215
I agree, the 50 years with no defects is testimony to good construction. You may be able to remove some collar ties without compromising the roof structure. Some builders stagger them anyhow. Check your code. If you live in a hurricane zone, the code may specify.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes