Do I have to repair the roof?

A 45 year house in NJ. It has 2 stories if you look from the backyard, but one story from the front. Therefore, the back roof has a low pitch. A recent check up found that due to years of snow load, the roof deck has two big visible sagging areas divided by a still straight line in the middle that has a supporting wall underneath that separates the 2 bedrooms under this roof.

Engineers were unable to get into the domer area to check. But notice the rafters in the front side is 2 x 8, maybe 2 x 10.

Do we have to rip open the roof to check the structure before winter comes? There is no leakage but not sure how soon we are going to have trouble.

 

Here is the image. Not sure why it could not be displayed here. Pls click the link.

http://img842.imageshack.us/i/roofing.jpg/

 

What makes anyone say that is from snow load and not something else?

My first guess would be that there are some rot issues. What's the slope on that roof? It looks to be very minimal. I believe the minimum for most shingles is 3/12. Right now I see a dip in the roof that looks like it's going to hold water. At best it will drain very slowly. That means water is going to back up under the shingles and rot your roof out. Which I kind of think it already has.

Why not punch a hole from the inside and take an initial peek in?

 

Definitely a low pitch roof. But not that low. Might be a shooting angle. Somebody said such roof should not be covered by regular shigles, but a whole pieace material. Digging a hole at the bedroom ceiling might be a good idea to check. But it will be very messy and may take some time to do that. Thanks a lot for your reply.

 

Use your attic access to check the condition and construction method from the attic.

Construct an attic access if you do not have one. Locate the ceiling joists with a stud finder and build the access hole between the joists.

 

The only way to avoid the interior mess is to rip off the exterior. I really feel like there is some rot on that roof. I don't have any working experience with roofs, but every time I see this kind of thing on tv, they rip off the roof and find damage underneath.

For the snow load idea to be plausible, it would mean broken framing. For your framing to break, it would have to be severely undersized.