I recently purchased a 50+ yr old Cap Cod that had an extended dormer installed to make an partial second story. From the ridge beam to the exterior wall is about 12 ft. Looks to be 2x4 and plywood with a rolled roofing. While the ends of the 2x4's are nailed into the pre-existing ridge beam should there be additional support provided or is that going to be enough to prevent the weight of a New York winter from causing collapse?

 

From when my cape was dormered the inspectors required two additional headers. The carpenter I had did not install them and I failed. The studs alone are not enough support they said.

They failed it for my protection.

My carpenter made the mods and all was happy.

Mike NJ

 

When you see structure done like this with snow country roof loads you have to question if it was ever inspected and approved, and this then leads to any other work that was done around HVAC, electrical, insulation etc. You may want to check with your building dept to see if any permits were pulled on the reno work, and if so which ones. I hope they were and this was just something the inspection missed. Adding headers as Mike needed to do is probably the easiest correction assuming that someone has simply not just finished attic space without considering all overall structural load requirements. Did you have an inspection done prior to purchase? Did the inspector check this out also?

 

The inspector did a visual inspection and stated that he did not believe that it would require any additional support. I think that dormer may not be the best term/correct term it was basically the roof on one side being lifted for most of the length of the house. In the end it is a roof section that is about 12 ft wide supported at one side by the exterior wall and at the other the ridge beam with a slight pitch to it (read nearly flat).

 

I would think you would need something with the way you describe your dormer. My dormer was small and the opposite of what you have. Mine has a peak style coming off the original cape roof. Only 7x7 for a bath and I still needed two heders.

You would figure with a peak you have less snow load. With a continuous flat dormer like yours with that large span, can you imagine the weight of snow on that?

I am not a carpenter and only stating what happen in my situation.

Mike NJ

 

What you have is called a dormer. This is a very common addition to cape cods. I am not an expert in such matters, but a 2x4 rafter sounds woefully undersized for a 12 ft span. The slopes on those dormers are very low and it is probably why you have rolled roofing. You probably should have a membrane roof on that and could expect some problems down the road as far as roof leaks.

 

I believe the correct term for what you are describing is a full shed dormer. A typical Cape has a very steep gable roof and lots of living space on the second floor is lost to the low headroom. A full shed dormer is a very common modification to a traditional Cape Cod style house.

Just my opinion but if you have 2X4 rafters spanning 12' in snow country they are undersized. I have a full shed dormer in a Cape and my rafters are 2X8.

 

I have never seen 2x4's used for ceiling joists or rafters unless they were part of a truss design. Are they 16 on center at least and are they tied together at least? Personally I wouldn't take that approach even on a carport though I am sure local codes wouldn't allow it anyway. You will have problems over time for sure with the roof sagging, not draining properly, and as was mentioned with asphalt rolled roofing material over it all you can expect future water penetration, especially as the roof sags and water starts to puddle unless you reinforce it all. Just my opinion.