Two roofs?

Home has an additional section of roof. Looking at the front of the home its the roof in the middle. They created this roof be building up another roof on top of roof trusses installed for the roof on the left. First time for me to see this. Wanted others opinions. Any carpenters out there? First picture is a side profile , notice the xtra framed roof above the hip truss. 2nd picture shows you the exterior roof and 3rd picture is from the scuttle looking up towars the peak.

nachi3.jpg

nachi2.jpg

nachi1.jpg

Bracing for the trusses? Deals with the multi-levels on roof?

I haven’t seen this before, either.

I really cant see anything wrong with it. The roof above was framed correctly to a hip rafter.

where are the carpenters when you need them.

Looks OVER framed James…nothing wrong with that…!!!

I don’t see anything wrong with it either, other than it is a ridiculous design. Architects just seem to like to complicate things when simplicity makes more sense. Oh well, it gives framing contractors and roofers more work, they make more money this way…

It may be over framed, or it may just be over lumbered. If the latter, it rates a careful look for structural soundness, as the framers may not have known what they were doing. The second picture gives the impression that the trusses are not plumb, though it may just be an illusion of the camera angle.

Jim King

Looking at the pictures, it appears that the girder trusses may be the wrong pitch, or undersized, hence the build-up. Scenario 2 would have the builder or owner changing the design mid-stream and rebuilding on top of the girders to give a multi-leveled roof design, more esthetically pleasing.
IMHO

Overframes are a common method of supporting a roof.
You frame (or roll the trusses) and sheath the first roof… in this case the furthest roof back… and that roof supports part of another roof.

I can’t tell from the pictures if that’s what this is, but your post describes an overframe.
I see a girder, rafters and a lot of bracing, but I don’t see a hip truss.

The pictures are hard to comprehend in framing techniques, and can only say that it is a convoluted framing mess.
I believe Kenton is trying to say that it is normal for framing Contractors to build the main roof truss systems with sheathing and then proceed to build on top of that main roof, additional roof dormers or gables to look like the one in the picture.

It appears that all this double framing, although might be structureall sound, might not be the most economicall and cleaneast. It also appears that some of the double framing is or are creating pin point loading on some of the trusses below that were not meant to carry this type of loading.
It would be hard for me to perceive that roof system as depicted in the picture was actually designed by a truss Manufacturer.

JMO

Marcel :slight_smile: :slight_smile:
</IMG></IMG>

Yep, what Marcel said. That roof has confusticated framing. The pictures make my head hurt.

Kenton, no hip truss but a hip rafter yes. The trusses extend left to right of the struture. Basically the higher roof in the middle is not supported by the truss but by conventional framing ( rafters and hip rafter) which was framed over the truss. Its looked structurally sound.

I took one more look and I think I understand.
It is an overframe. Typically they frame and sheath the first roof, then use that to support framing for the second roof. Framing for the second roof would usually rest on sheathing.

In this case they didn’t sheath the first roof, but framed the upper roof right on top of lower roof framing. That’s why it looks so complicated in the picture. Well… not the only reason. It looks like they used unique framing methods for the upper roof, but as long as it looked solid and felt solid there’s nothing to call structurally.

only photo I could find

http://www.littlesunlighthomes.com/images/2.3.03/overframe.jpg

imagine hip roofs, only with no sheathing. Also, this is not built well. The bottoms of those jack rafters should rest not directly on OSB, but on a pair of ledgers, one on each side, nailed right to the roof so that when it’s sheathed they’ll have solid sheathing nailing at the valley to help hold the roof down in high winds. Each sheet of sheathing on a roof should have solid nailing around the entire perimeter of the sheet.
As it’s framed now, sheathing will be nailed to each rafter, but the overframe will only be connected to the main roof by a few toenails through the bottoms of the rafters.

Most roof are blown off not by wind getting under them and lifting them off, but by extreme low pressure created on the downwind side of the roof. The roof is sucked right off the house. It’s the same principle that moves a sailboat through the water.

Kenton, besides the fact of no ledger board for the jack rafters as you pointed out, it appears the OSB sheathing was installed parallel to the rafters. Is it the picture or is that the way it was done?

Marcel :slight_smile: :slight_smile:

Good catch, Marcel. It looks that way to me too.

Thanks Kenton;

The only concern with the unorthodox framing of James’ post would be not knowing how much weight is pin loaded on some of the truss rafters that you see in his second picture.

It might be alright, but we can’t see the whole picture.

I guess if James is comfortable with it, fine by me.

Thanks

Marcel

I see what you man, Marcel. Like where some of those little 8" blocks rest on the truss top chord. In evaluating things like this I try to visualize the failure and imagine what kind of forces could cause it. In this case it would have to be a big snow load in addition to 3 layers of asphalt roofing and maybe some wind … to me anyway. Hard to imagine it failing without being weakened by decay.
That’s mostly a matter of personal curiosity. As a home inspector, if I’m not sure I pass on the liability by saying that.

[quote=bjones1]
Looking at the pictures, it appears that the girder trusses may be the wrong pitch, or undersized, hence the build-up. Scenario 2 would have the builder or owner changing the design mid-stream and rebuilding on top of the girders to give a multi-leveled roof design, more esthetically pleasing.

I think I have to agree bjones
something was messed up during the framing and rather than send the trusses back and have the wait time for new ones they just frame over and transfered the load down to the trusses they started with

I’ve been a carpenter since way back when we still used hammers instead of nail guns and have never seen anything like this. I agree that someone either changed their mind halfway through a job or didn’t really know what they were doing and just kept adding lumber whereever they could…how would I report it? “Roof framing appears unorthodox but adaquate”