Adding a shed roof to the backyard

[DoubleStud]

I get this inquiry all of the time and usually the roof goes over a big sliding door and or a window. I usually tell them I will need to know the existing headers of the sliding door and window. More than likely you will need a stronger header (or need to be beefed up). Is there another way to avoid this? Perhaps using a beefier ledger to support the rafters, and the ledger will act as a header over the existing opening? What do people typically do? I see this renovation all of the time? Maybe they just add the roof without even worrying about the header? Homeowners usually expect exterior work and do not expect needing a new header and do interior finish work.

 

[XR250]

I have done it with a beefy ledger before. Can be tough to get the load out at the ends though. Also, need to make it stiff AF or else it ain't doing much.

 

[jerseyshore]

I'd say upwards of 50% are unpermitted. The next 30% no one cares about the headers and they omit it from the plans entirely. The next 15% don't actually check it they just write "exist header to remain" on the plans. The remaining 5% are people like us who actually check things. But the reality is who is opening their sliding door when the roof is loaded with snow so the existing header is probably down the list of potential problem areas for something like this.

 

[phamENG]

If there's no way around it - beefy ledger, beam above, etc. - then at the very least I'll list the minimum required header size and put the onus on the contractor to verify the size during construction. Most homeowners don't want to rip open a wall like that - it's often months before construction and there's always a chance they won't build it at all.

 

[phamENG]

To add to my last comment - this probably doesn't matter in Colorado, but for posterity's sake if somebody from the south/south east is reading this - make sure you consider variations in reference design values. For instance, if I'm checking to see the minimum size for an existing header of a house built before 2013, I'd be looking at the older Southern Pine design values. They changed in 2013, but it was not retroactive. Everything in service before the change keeps the higher values. This is an important distinction and one that can cause issues when communicating it to a contractor. For instance, I might say that the minimum existing header size is (3)2x12, but if it's got (3)2x10 they have to use LVLs now.