Adding Racking Resistance to an existing house?

**Nate R** · 05-07-2008, 12:12 AM

Our house was built in the early 20s w/ reused lumber. The studs had been cut in for a diagonal 1X4 for it's original use. But no one used that when they built this house. (Some of the studs w/ let ins are flipped around, so I know there was never any diagonals on this structure)

The outside is sheathed w/ 1X6 or 1X8 boards. Then there's wood siding over that, and vinyl over that.

Later this year, I'll be pulling everything off down to the original sheathing boards. I'm also exposing a couple of the walls inside the house w/ interior work.

Looking for suggestions on the easiest way to add racking resistance to the house. Visually it appears as if there has been some slight racking over time. I just don't want to worry about it moving back and forth, or moving ever again.

Do I have to nail 3/8" OSB over the entire structure, or is there an easier method to use?

**statjunk** · 05-07-2008, 04:39 AM

I asked this question a long time ago and did some research on it. I only removed one of the existing ones so I was able to use plywood with screws spaced about 2" apart to achieve the "racking" strenth.

You can also take a piece of 1x4 and cut the ends at a diagonal. Trace it out along the studs and chisel the wood out.

If you went with the 1x4 you'd likely have to consult an architect to determine the proper placement.

Tom

**jimbo** · 05-07-2008, 06:41 AM

Out here in earthquake country, shear strength ( racking resistance, as you say) is achieved in several ways, but I think the main thing is plywood. At the corners, plywood sheathing is installed according to a specified pattern, and as mentioned by statjunk, they screw and nail it like they owned stock in the nail company! I am not a builder...don't know the exact spec, but as he said, it is like every 2" all the way around and in the field. The also use a lot of metal from StrongTie, but that is mostly I think in the tie down area....to keep the house from jumping off the foundation, and to keep the roof and second floor attached to the rest of the house.

Last year when my daughter had a room added on, they opened up a big chunk of the front wall to make a "great room". Because that area of shear was no longer present, the other half of the entire front wall of the house had to be opened up and plywood shear installed.,

**Lakee911** · 05-07-2008, 09:23 AM

There is a metal T shapped product available that you let in with a small diagonal saw cut and then fasten it to the studs. I can't remember the name of it though. I saw it at a blue or orange box store. Probably not as good as plywood though.

Jason

**Nate R** · 05-07-2008, 10:24 AM

Thanks! Anyone know where I can go to find more info on this? (What OSB thicknesses are acceptable, nailing patterns and sizes, etc)

**jadnashua** · 05-07-2008, 12:25 PM

I think personally that I'd use plywood for stiffening rather than osb. I don't have quantitative values, but think if you check, it is less likely to fail.

**BigLou** · 05-07-2008, 02:16 PM

Nate
just take out the sheating boards on the corners and install a sheet of 3/4 ply standing up with lots of nails as long as you catch one or preferably both plates you will be more then stong enough

Lou