Alternative to collar ties

Proby · 08-13-2010, 11:08 PM

I'll probably get over there to do some work on the weekend, I'll take some pics to show you what it looks like.

Willie T · 08-13-2010, 11:09 PM

BTW, if you have SketchUp, and want these SKP files to play around with, PM me with an email address, and I'll send them along to you.

Willie T · 08-14-2010, 09:44 AM

Quote:

Originally Posted by GBR in WA

1. Do you have ceiling joists below to walk on that are bearing on the outside walls? What size and how far do they span?

2. Collar ties are in the upper 1/3 to hold the rafter peaks and the ridge board together in a high wind. Required by the Southern Building Code only, as far as I've read.
It sounds like they are nailed to the middle of the hip jacks and the valley rafter?

3. Have you called the local B.D. and asked them if collar ties are required?

Nice drawing Willie. FYI- valley/hip jacks always run up and down, never side to side.... but I see what you meant.

Be safe, Gary

I'm certainly with you there. But the way the OP described it with collar ties joining the valley and hip jacks, I couldn't envision any other way they might have done it. I'm kind of lost as to how they would have installed collar ties on jacks perpendicular to one another.

Trust me, the way I drew it would hardly be a choice I would make for my own work.

(The picture below is kind of what Gary is talking about....... and the standard way most everyone frames...... I couldn't find anything exactly like Proby described and showed in his drawing.)

Proby · 08-14-2010, 10:17 AM

That valley in there is the way mine is framed.

I didn't put the valley jacks into my drawing because I got lazy towards the end and they really don't effect the collar tie question.

Proby · 08-14-2010, 10:23 AM

You see where I put the red line? Those rafters have collar ties spanning across to the other side of the roof. The problem is that those collar ties are too low. I would like to remove them and find an alternative.

Willie T · 08-14-2010, 10:48 AM

OK, I think I finally see what you mean. The collar ties attaching the rafters toward the center part of the "Bump Out" are higher because the peak of the "B O" is, naturally, higher.

So, in order for them to run collar ties, front to back, where the valley begins to descend the slope of the main roof, each collar tie had to be installed lower than the previous one above it. And they keep getting lower and lower till the bottom ones are probably only a couple of feet above the ceiling rafters. Right? (Much like I drew in Post #15, right?)

If I finally have it right, there may be hope for you. But it may require engineering approval and an OK by the Building Department.

Collar ties are usually only required on every other rafter. So, you can probably surmise that the uplift they are expected to contain is not all that great. (Otherwise they would be required on EVERY rafter.)

So, it may be possible to install a long, perpendicular piece across the midsection of all the "Bump Out" rafters, spanning all the "B O" rafters, tying them all together at about the center of the longest ones. (This might have to be steel)

From there, it just might be possible to get away with only two fairly high collar ties, one connected to each of the second longest rafters. (The ones to either side of the center rafter of the "B O".)

This is, admittedly a long shot. But an engineer just might see it as workable. Of course all this hinges upon being able to solidly tie all the "B O" rafters together somewhere around their midpoints.

But, no, I don't think you could get away with just removing all the low collar ties...... not without somehow reestablishing some uplift prevention to replace them. And I think it would probably take more than clips to either the valley or hip rafters.

BUT............. If you blow up the picture above and look carefully, you will see collar ties installed all across the main roof. However the hip where you drew your line doesn't appear to have any at all. Up North, you guys often don't need to jump through the wind pressure hoops tropical areas have to. So...................... who knows just what the building dept may say?

Proby · 08-14-2010, 11:27 AM

Quote:

Originally Posted by Willie T

OK, I think I finally see what you mean. The collar ties attaching the rafters toward the center part of the "Bump Out" are higher because the peak of the "B O" is, naturally, higher.

So, in order for them to run collar ties, front to back, where the valley begins to descend the slope of the main roof, each collar tie had to be installed lower than the previous one above it. And they keep getting lower and lower till the bottom ones are probably only a couple of feet above the ceiling rafters. Right?

Yes, exactly. But what they did was they put ALL of the collar ties at a single height, about 5' off of the floor, instead of making some higher and some lower.

Quote:

(Much like I drew in Post #15, right?)

Similar, but my collar ties are going to the B.O. rafters themselves. In your image the ties are running into the hip board.

Quote:

If I finally have it right, there may be hope for you. But it may require engineering approval and an OK by the Building Department.

Collar ties are usually only required on every other rafter. So, you can probably surmise that the uplift they are expected to contain is not all that great. (Otherwise they would be required on EVERY rafter.)

So, it may be possible to install a long, perpendicular piece across the midsection of all the "Bump Out" rafters, spanning all the "B O" rafters, tying them all together at about the center of the longest ones. (This might have to be steel)

From there, it just might be possible to get away with only two fairly high collar ties, one connected to each of the second longest rafters. (The ones to either side of the center rafter of the "B O".)

This is, admittedly a long shot. But an engineer just might see it as workable. Of course all this hinges upon being able to solidly tie all the "B O" rafters together somewhere around their midpoints.

But, no, I don't think you could get away with just removing all the low collar ties...... not without somehow reestablishing some uplift prevention to replace them.

BUT............. If you blow up the picture above and look carefully, you will see collar ties installed all across the main roof. However the hip where you drew your line doesn't appear to have any at all. Up North, you guys often don't need to jump through the wind pressure hoops tropical areas have to. So...................... who knows just what the building dept may say?

Makes sense.

I did notice how all the rafters on the B.O. of the roof you pictured didn't have collar ties so I was thinking the same thing.

I'm surprised that metal clips (like hurricane clips) aren't enough to secure each rafter to the board.

**Gary in WA** · 08-14-2010, 01:01 PM

You don't need ties on hip jack or common rafters. The only application is opposite common rafters on a gable roof, built under the Southern UBC. Ask locally, if still in doubt.

Be safe, Gary

Willie T · 08-14-2010, 02:33 PM

There ya go. Yank 'em.

08-13-2010, 11:08 PM	#16
Proby Electrician Join Date: Jul 2010 Location: NJ Posts: 818	Alternative to collar ties I'll probably get over there to do some work on the weekend, I'll take some pics to show you what it looks like. __________________ Anything fun is either illegal, immoral, or fattening.

08-13-2010, 11:09 PM	#17
Willie T Old School Join Date: Jan 2009 Location: St. Petersburg, FL Minds of moderate caliber ordinarily condemn everything which is beyond them. Posts: 3,429	Alternative to collar ties BTW, if you have SketchUp, and want these SKP files to play around with, PM me with an email address, and I'll send them along to you. __________________ "True eloquence consists in saying all that is necessary, and only that which is." François Duc de La Rochefoucauld Willie T

08-14-2010, 10:17 AM	#19
Proby Electrician Join Date: Jul 2010 Location: NJ Posts: 818	Alternative to collar ties That valley in there is the way mine is framed. I didn't put the valley jacks into my drawing because I got lazy towards the end and they really don't effect the collar tie question. __________________ Anything fun is either illegal, immoral, or fattening.

08-14-2010, 10:23 AM	#20
Proby Electrician Join Date: Jul 2010 Location: NJ Posts: 818	Alternative to collar ties You see where I put the red line? Those rafters have collar ties spanning across to the other side of the roof. The problem is that those collar ties are too low. I would like to remove them and find an alternative. Attached Thumbnails __________________ Anything fun is either illegal, immoral, or fattening.

08-14-2010, 10:48 AM	#21
Willie T Old School Join Date: Jan 2009 Location: St. Petersburg, FL Minds of moderate caliber ordinarily condemn everything which is beyond them. Posts: 3,429	Alternative to collar ties OK, I think I finally see what you mean. The collar ties attaching the rafters toward the center part of the "Bump Out" are higher because the peak of the "B O" is, naturally, higher. So, in order for them to run collar ties, front to back, where the valley begins to descend the slope of the main roof, each collar tie had to be installed lower than the previous one above it. And they keep getting lower and lower till the bottom ones are probably only a couple of feet above the ceiling rafters. Right? (Much like I drew in Post #15, right?) If I finally have it right, there may be hope for you. But it may require engineering approval and an OK by the Building Department. Collar ties are usually only required on every other rafter. So, you can probably surmise that the uplift they are expected to contain is not all that great. (Otherwise they would be required on EVERY rafter.) So, it may be possible to install a long, perpendicular piece across the midsection of all the "Bump Out" rafters, spanning all the "B O" rafters, tying them all together at about the center of the longest ones. (This might have to be steel) From there, it just might be possible to get away with only two fairly high collar ties, one connected to each of the second longest rafters. (The ones to either side of the center rafter of the "B O".) This is, admittedly a long shot. But an engineer just might see it as workable. Of course all this hinges upon being able to solidly tie all the "B O" rafters together somewhere around their midpoints. But, no, I don't think you could get away with just removing all the low collar ties...... not without somehow reestablishing some uplift prevention to replace them. And I think it would probably take more than clips to either the valley or hip rafters. BUT............. If you blow up the picture above and look carefully, you will see collar ties installed all across the main roof. However the hip where you drew your line doesn't appear to have any at all. Up North, you guys often don't need to jump through the wind pressure hoops tropical areas have to. So...................... who knows just what the building dept may say? __________________ "True eloquence consists in saying all that is necessary, and only that which is." François Duc de La Rochefoucauld Willie T Last edited by Willie T; 08-14-2010 at 11:26 AM.

Alternative to collar ties