Why not have the carport free standing and NOT attached to the home, but sneak it up close enough so that you can use flashing to flow the water off the trailer onto the carport.
this way, both are independant and one will not pull down on the other.
If this is out of wood, you need to take special care, but you can buy a prefab metal carport for allot less than all the wood and stuff for the wooden one.
You would need to make sure that the joists, metal or wood are closer to each other to support that kind of weight and the spans from post to post are also accurate.
Since this accident happened once, consider having this done professionally.
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