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Re: 2nd floor addition

[Subject Prev][Subject Next][Thread Prev][Thread Next] While you could rebuild the wall completely, I have removed the top plates, and lapped new stud next to existing. Typically the new do not go to the sill plate, and the length has been determined by existing plumbing and/electrical in the wall. Attention must be paid to fully develop the connection between the original and 'sistered" stud for both loads perp to wall and vertical loads. Vertical loads can easily be resolved by adding a short section of stud directly above the existing, and having the sistered stud tie the two together. The plywood panel size isn't an issue as you can splice plywood at approximate mid wall ht with blocking between the studs. The one foot extension of the lower wall probably isn't a problem with new plywood, as the chances are good the original structure doesn't have plywood to begin with, and therefore the lateral capacity of the lower level probably is substantially below requirements for a two story house. Remember that when you increase the loads or decease the capacity of existing structures, the affected elements/portions must be brought up to the current code. Considering the 97 code, I wouldn't expect any existing structures to be capable of carrying additional seismic loads without some retrofit to the original structure.

Steve Privett

GaryD wrote:

Another simple question (probably) all the wood design experts.

I thinking about the best way to approach an existing 1 story house that is getting a 2nd floor addition. Normally, I would assume that the roof gets removed, floor framing is placed, and the 2nd floor platform walls will sit over the lower walls just like in a new house. I have a situation where we are required to raise the original lower floor ceiling height from 8 ft to 9 ft.What are the various methods to achieve this? I was thinking that simply adding cripple studs would not be good to make up the 1 ft difference because I would be relying on a 1 ft strip of plywood when I was taught not to use plywood with less than 24" in shear panels. To complicate things, the 2nd floor ceiling height is 10'-6" so I would have another joint since I believe plywood is only available in 10' max sheet sizes.

Thanks for any comments .

Gary



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