Reinforcing deeply notched rafters

[JJW]

Hi,
I’m about to start building a sunroom attached to the back of our house on a concrete patio. Plans have been approved, but yesterday I realized a major oversight: There will not be enough room for the existing French doors from the house to swing out under the rafters. The ledger will be attached directly above the doors and under the rain gutter without any wiggle room for raising it. Rafters are 2x8”, but will need to be notched about halfway through (effectively leaving a 2x4) to accommodate a fully open door. I asked my city code contact what I can do about this. My idea was if a steel plate can be mounted on one or both sides of the affected rafters for reinforcement. He referenced R802.7.2 and R502.8.1 for why the rafters cannot be notched that deeply, and then R301.1.3 for alternative engineering without saying whether my idea might be feasible. I’m hoping to avoid hiring an engineer if possible. Ideas?

 

[bill1952]

Simplest would be to change doors to swing in.

I believe a prescriptive design solution might be to double (or tripple?) rafters to left and right of doors and header off those joists, with 2x4 rafters over door swing area, but doors would only open 90 degrees.

There may be other solutions but hard to know without more details. Only an engineer can determine if and what size and details adding steel will work. Guessing span is 10 to 12 feet it's likely substantial amount of steel. A simpler to build engineered solution might be a stressed skin panel, but not something every engineer would do.

 

[JJW]

No space to have them swing in. 10 foot span.

 

[mark handler]

Contact an Engineer or Architect.

 

[Beniah Naylor]

Hi,
I’m about to start building a sunroom attached to the back of our house on a concrete patio. Plans have been approved, but yesterday I realized a major oversight: There will not be enough room for the existing French doors from the house to swing out under the rafters. The ledger will be attached directly above the doors and under the rain gutter without any wiggle room for raising it. Rafters are 2x8”, but will need to be notched about halfway through (effectively leaving a 2x4) to accommodate a fully open door. I asked my city code contact what I can do about this. My idea was if a steel plate can be mounted on one or both sides of the affected rafters for reinforcement. He referenced R802.7.2 and R502.8.1 for why the rafters cannot be notched that deeply, and then R301.1.3 for alternative engineering without saying whether my idea might be feasible. I’m hoping to avoid hiring an engineer if possible. Ideas?

Your idea might be feasible. However, a city building code professional does not deal with creative ideas that might be feasible - if the code doesn't have a way to do that in the code book, a code professional is not going to sign off on it without substantiation from an engineer. Creativity is the purview of engineers and architects, but a city building department has to limit themselves to what is in the book. This is as much to protect you as the consumer and contractor from overreaches as is it is to protect themselves from liability.

If you get an engineer to sign off on it, it sounds like they will accept it. Otherwise, you may need to find another method to comply.

 

[Beniah Naylor]

It is tempting to troubleshoot and problem solve, but if you don't know how to do the calculations to prove that it will work with actual numbers and loads, it is best to defer to the code. If the code won't let you do what you want, you need an engineer or architect who knows how to do the calculations to prove it will be safe.

 

[e hilton]

Do you need the overhang for the sunroom roof? Maybe cut the rafters flush with the exterior wall, build the new roof extension a little higher.

 

[JJW]

Thanks all. It sounds like I’ll be calling an engineer!

 

[Saugie53]

Just out of curiosity if the bottom of the ledger/rafters is just above the top of the rough French doors and pitch downward to a point where they will intefere with the doors opening what will your finished ceiling height be? Are you going to have issues with meeting the minimum ceiling height required by code?