Wall Shoring

[Handyone]

This is a long description of what I want to do, but please bear with me and hopefully I can get some help.
I'm remodeling a condo, a first floor unit where there is a second unit above. 3 load bearing walls are being effected. The first is simply burying a beam in the ceiling. The second is being moved about 4' to create a larger room (ceiling joists will need to be replaced with longer ones). The third is being moved about 2' to create a larger room.
The first two walls run perpendicular to the joists. I have no problem shoring up these walls while I build the new walls. I will build temp walls on both sides of the old wall.
My problem is the 3rd wall. It runs parallel with the ceiling joists. I assume it is considered load bearing because there is a wall directly above it in the 2nd story unit. The engineer wants the new wall to be a shear wall with a new footing.
Long story short, how can I remove this wall while the footings are poured and support the joists above?
I was thinking of making a "hallway" of sorts. Place like a 4x8 or 4x10 header every 4' or so perpendicular to the joists with trimmers. Basically it would look like 4 or 5 doorways with room through them to dig and pour new footings. The wall is about 12' long.
Am I on the right track here. Or is there a better way?
Thanks for your time and I appreciate any help.
Brian, San Diego, CA

[Joe.Carrick]

Hi Brian,

Got some problems....

1. The ceiling joists are really floor joist for the unit above. Changing the length could be a real problem, depending on what size they are and what the loads are. It's very likely that the wall above will be carrying loads down that the joists will not adequately support.

2. The wall that runs parallel to the joists may or may not be bearing, even with a similar wall above. Usually it would not be bearing and would not need a footing.

If you can find out who built the project in the first place you might be able to get a set of drawings - or the condo association may have them. If you can get drawings an architect/engineer will be able to determine what you can and can't do as well as what needs to be done to effect your remodel.

Doing this work with another unit above is something you want to be really careful about.

Joe

[Joe.Carrick]

BTW, what you pay for an Architect for this job will probably be less than the cost of cutting out the slab and putting in new a new footing that isn't needed.

[Handyone]

"Long story short, how can I remove this wall while the footings are poured and support the joists above?
I was thinking of making a "hallway" of sorts. Place like a 4x8 or 4x10 header every 4' or so perpendicular to the joists with trimmers. Basically it would look like 4 or 5 doorways with room through them to dig and pour new footings. The wall is about 12' long.
Am I on the right track here. Or is there a better way?
Thanks for your time and I appreciate any help."


1. The ceiling joists are really floor joist for the unit above. Changing the length could be a real problem, depending on what size they are and what the loads are. It's very likely that the wall above will be carrying loads down that the joists will not adequately support.
Answer:
Thanks Joe,
An engineer has already calculated loads and so forth. I have a full set of drawings. I also have access to the condo above. I left a few things out to save time typing but, like I said the place has been engineered. There are laminated beams I'm putting in, shear walls and a few other seismic upgrades.

2. The wall that runs parallel to the joists may or may not be bearing, even with a similar wall above. Usually it would not be bearing and would not need a footing.
Answer:
It is load bearing. Please look at my quote above from my original post. My question is how to support that parallel wall while the footings are poured. The footing must go in per plan. (also new wall is a shear wall w/ 3/8" struc 1 ply).
Like I said, I don't have a problem supporting the above floor joists while building a new wall perpendicular to the joists. I will simply support the joists on either side of the new wall with temporary walls or post shoring. The problem is the wall parallel w/ the joists. Like I quoted above, My idea is to build a sort of "hallway" around the old wall, with headers every 4' or so.
Follow me? I've built temp walls before but I have never had to remove a load bearing wall parallel with the floor joists above.
Thanks again,
Brian

[Joe.Carrick]

Hi Brian,

If you have the original drawings, then you should have the foundation plan as well. Is there an existing footing shown beneath all of these walls? If so then I'll agree that they are bearing walls.

Now as to your question of the shoring for the wall that's parallel to the joists. Creating a "mine-shaft" as you describe should work. Your engineer whould be able to tell you how to do it. A shear wall not only needs to have the plywood paneling proper nailed, but it will need to be properly connected to the floor above to transfer loads from the wall above (lateral loads) over thru the floor diaphragm and down into the new shear wall. Does the existing wall have plywood shear paneling?

In any event, you will need a building permit for this work. Anything that changes the structure in CA requires a permit. So, if you have one - OK. If not then don't do anything until you get the permit.

What recommendations/requirements did the engineer give you for the floor joists where you are moving the bearing wall 4' ?

As a Licensed Ca Architect, I have a hard time believing that those joists won't have to be at least increased in depth 2" and/or perhaps sistered on both sides. The wall above is probably supporting the roof and the joists are only designed to support the floor loads of the upstairs condo. By moving the wall, you increase the span of the joists by 4 feet and very seldom would joists of the same size suffice to support the increased floor loads. Imposing a point load supporting the roof is even a bigger problem.

Anyway, if you have an engineer and a permit then you should use the engineer to advise you and get the building inspector's approval of shoring , etc before removing anything. The building department won't accept any responsibility, but the engineer should have insurance to cover any errors on his part.

[Joe.Carrick]

Assuming that everything is OK as far as the structure is concerned for your changes, why not just cut out the slab next to the new shear wall without removing the existing wall or footing. Excavate adjacent to that footing for the new footing and put in the rebar and concrete.

Then build the new wall _before_ taking out the existing.

[Handyone]

Thanks Joe,
I'll do the mine shaft thing. The existing wall is not a shear wall and I seriously doubt if there is a footing under the old wall. The wall is currently supporting a double 2 x 10 above that spans approx. 24' and runs directly at the rear of a fireplace opening in the ceiling/floor joists.
As far as the new floor joists above, the plans call for the new joists to be 2 x 10's (same as old). One side of the room will be a bearing point (existing bearing wall). The other side of the room is the wall I'm moving 4'. This new wall requires footings and holddowns. (another shear wall). The room is increased in length to a total of 14'. Also approximately at the middle of the room, there will be a new laminated beam to replace the existing (3) 2 x 10's.
Also the other bearing wall in this room (the wall I'm not moving), needs to have footings under the posts on either side of the french doors. This wall will also be a shear wall. I do have permits, and the city did have some doubts about the strength of the new configuration. The engineer assured the city that nothing we are doing will effect the building itself (Hmmmm). And the city approved the plans. The new plans do seem much stronger though. If you consider there were no shear walls before, probably no footings under posts, etc. Now each new shear wall requires footings; and posts will have (approx. 27 x 27 x 12) footings.
Anyway, I'm gonna take your advice and go to the inspector. I didn't know they would give you advice on shoring techniques. Please let me know what you think.
Thanks,
Brian