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View Full Version : Rafter and ridge issues- shed dormer



Adam DeAngelo
05-12-2008, 10:18 AM
I am new to this site and just wanted to get a couple of opinions. I recently framed a shed dormer onto my cape cod style house. The dormer wall spans 28' in length & 6'9" high, with the overall length of the house 32'. I recently finished and have to get an inspection. There are two issues I think the inspector may have. I want to see if these will be issues and what I can do about them before the inspector comes.

1. The ridge size. The existing roof, an 8 pitch, was framed with 2x6's and no ridge board. The rafters on the shed dormer, which is a 3 pitch, are 2x10's. I used a 2x6 as the ridge board (looking back, I have no idea why). The 2x10's hang below the board about 4 inches. The 2x6 portion of the roofs hangs below the ridge about 2 inches. I did not specify a ridge size in my submitted plans. My question is will this be a problem. If so, can I slide a second 2x6 between the rafters to compensate?

2. The rafters of the shed dormer are offset from the original rafters. I framed the dormer wall at 16" centers. However, I neglected to line the wall studs up with the existing 2x6 rafters on the other side. As a result, once the wall was lifted the wall studes did not line up with the existing rafters. I chose to put the dormer rafters over the wall studs and offset them from the original 2x6 rafters, rather than line the rafters up and have them offset from the wall studs.

Just wanted to get an opinion on these two issues. A couple of additional facts- There are 2x6 collar ties at 16" centers and a height of 8'. Since the rafters didn't line up, I installed a nailing board the length of the existing roof and cut that end of the collar ties at an 8 pitch. The roof is a standing seam metal roof. I built this just before the winter and had about 3 inches of pure ice on the roof and have had no problems.

imported_John Smith
05-12-2008, 04:50 PM
I would hire a licensed/certified/qualified home inspector in your area to assist you with this.

Jim Luttrall
05-12-2008, 05:04 PM
Adam, sounds like you have some legitimate concerns that need to be addressed even if your municipal inspector lets it slide.
My advice would be to hire either an experienced carpenter that would be willing to work with you to correct the issues before the framing inspection or find a sympathetic home inspector that is willing to go above and beyond to help you fix the issues before the red tag goes on from the municipal inspector. Of course you could also get a structural engineer to design a fix.

Gunnar Alquist
05-12-2008, 05:48 PM
1. The ridge size. The existing roof, an 8 pitch, was framed with 2x6's and no ridge board. The rafters on the shed dormer, which is a 3 pitch, are 2x10's. I used a 2x6 as the ridge board (looking back, I have no idea why). The 2x10's hang below the board about 4 inches. The 2x6 portion of the roofs hangs below the ridge about 2 inches. I did not specify a ridge size in my submitted plans. My question is will this be a problem. If so, can I slide a second 2x6 between the rafters to compensate?

2. The rafters of the shed dormer are offset from the original rafters. I framed the dormer wall at 16" centers. However, I neglected to line the wall studs up with the existing 2x6 rafters on the other side. As a result, once the wall was lifted the wall studes did not line up with the existing rafters. I chose to put the dormer rafters over the wall studs and offset them from the original 2x6 rafters, rather than line the rafters up and have them offset from the wall studs.

Just wanted to get an opinion on these two issues. A couple of additional facts- There are 2x6 collar ties at 16" centers and a height of 8'. Since the rafters didn't line up, I installed a nailing board the length of the existing roof and cut that end of the collar ties at an 8 pitch. The roof is a standing seam metal roof. I built this just before the winter and had about 3 inches of pure ice on the roof and have had no problems.


Adam,

Without pics, it is difficult to fully grasp the conditions. In addition, it is difficult to read the mind of an unknown inspector. The reality is that we all see stuff that passed inspection that should not have.

Putting in an additional 2x6 below might satisfy the building inspector or it might not. In my neck of the woods, the building inspector would want a letter from an engineer saying it was OK.

The rafters should have lined up with each other. Once again, I see lots of rafters that do not line up and are passed. Once again, there is often a difference between what passes inspection and what is right.

For some reason, I am completely unable to visualize the conditions in your last paragraph.

Richard Moore
05-12-2008, 06:18 PM
I agree the rafters should have lined up, with a full depth ridge board. This bit really worries me...

"A couple of additional facts- There are 2x6 collar ties at 16" centers and a height of 8'. Since the rafters didn't line up, I installed a nailing board the length of the existing roof and cut that end of the collar ties at an 8 pitch."

That sounds like a very, very weak connection for the collar ties. If I'm reading that right, I would expect the nails to simply pull out under enough load. You have 28' of roof that is going to want to flatten under a heavy load. The collar ties will be under tension and are there to prevent your walls from bowing out. The normal connections, nailed to the sides of the rafters works well, but what I am picturing you have done, won't.

I really can't see how a building inspector would let this slide...assuming he actually gets out of his car. As Jim said, even if he does, I think you have created a roof/wall system that could eventually fail.

The fix??? For the roof itself, I'd say do it again...properly. For the city inspector, you might try a large wad of cash. (JK on that last).

Jerry Peck
05-12-2008, 06:36 PM
Adam,

From what you are describing (as I visualize it in my mind) - you do have a problem, make that several problems.

I would not bother with the home inspector in this case, I would do what a qualified home inspector would recommend you to do - call a structural engineer.

Have a structural engineer come out and look it over, they may (after seeing it first hand) be able to come up with a simple solution where the solution looks to be larger for us who have not seen it.

Do this before the inspector comes out, make the corrections the structural engineer says to make, and the, when the inspector comes out, hand him/her the structural engineers letter stating two things:
1) 'This is what needs to be done.'
2) 'The work was done in accordance with the engineering design.'

The latter 2) is more important than the former 1) - no one really cares 'what needs to be done', they really want to know 'was it done according to the engineering design', that's the key.

I think you've got some issues, which are not insurmountable, and your best expenditure of money - it seems to me - would be to go straight for the structural engineer on this.