Mud Sill Tie down

[RWebb]

I'm trying to do a little bit of Earthquake strengthening to retrofit my house just in case while I have the ceiling out of a room downstairs (this part of the house is dug into the side of the hill).

There were square nuts on all the studs that stick up from the concrete wall (this one is about 8 ft. high). The house was built in 1963. Some of these square nuts were not even tightened down all the way -- dunno if they worked themselves loose over the decades or the original workers were sloppy.

Here is my upgrade: a Simpson Bearing Plate (much thicker than a washer) and a normal type nut on the 1/2" stud. Note, I had to chisel away part of that rim board to get some space for the Simpson Bearing Plate.







Any thoughts on what else to do here?

- torque them down? (if so, what would be the spec.?)

- maybe squirt some wick-in green Loctite on the threads?

[look 171]

Looks fine to me. I am not sure if i like that foam. Many people use it to seal a hole from the outside. The foam acts like a sponge and retain all the water and do not allow it to dry causing rot. Careful with that. You guys don't have many earthquake up there. No loctite or tq spec needecd.

[RWebb]

thx

I used the spray foam from the inside.

we don't have as many earthquakes, but the ones we do have are projected to be larger than the Calif. quakes

[A930Rocket]

It was probably tight years ago, but the wood has dried out and shrunk since then. That's why it was loose.

To do it right, you would really need to start at the footer and work you way to the roof ridge beam. Also, adding or properly nailing existing OSB or plywood on the entire exterior.

Some if it wouldn't be practical, like the footer to sill plate and band. Next would be strapping the first floor walls to the second floor walls, etc. Then the second floor wall to the rafters. And finally, the rafters to the ridge beams. Shear walls on the interior will help as well.

[Bill Douglas]

Originally Posted by A930Rocket

Next would be strapping the first floor walls to the second floor walls, etc. Then the second floor wall to the rafters. And finally, the rafters to the ridge beams. Shear walls on the interior will help as well.

Yup, Rocket Man knows his stuff. The idea of strapping is so after the house boggies around in the earthquake, it goes back to it's orgional location.

[Bill Douglas]

Umm, a couple of things stood out in particular after the Christchurch earthquake here in NZ with residential houses. The first one can't be helped and that is the ground under the house took a new level and/or therre was a split in tghe ground. The second one can be helped. The houses got such a shake up that some slipped off their foundations and the nails pulled out that hold the wall to the rafters and they relocated to a differnt spot.

Strapping does help. The straps look a bit mamby pamby, but with a number of them on the job does keep the house in it's regular shape.

There were a few photos of similar bungalows next to eachother, one looking OK and the other semi collapsed. A case of one with strapping and the other without.

[looneybin]

pick up a Simpson Strong Tie catalog at your local lumber yard, there is an entire section on seismic retrofit hardware

[RWebb]

thx all - no work recently as we had a nice storm and 2 days w/o electricity (I am at the downtown office which does have elec.).
I've been looking at Simpson's web site & talking to them about this...

I did put shear walls on the interior of the main bedroom a couple of years ago - that room is also downstairs, but opposite this one. It is the part of the daylight basement with no concrete stem walls (i.e. out away from the hill where they dug it out for this room).
- I realize now, that I should have done that room differently & put in a 3x4 or 4x4 so I could nail each of the plywood panels to the same "stud" - c'est la vie.

re tying it all together with straps - I was looking into that, but when I cut into the sheetrock I discovered that on the exterior wall where the joists land (adjacent to the wall the pic above was taken on), there is a "pony" wall (I think they call it that) i.e. a short wall of studs on top of a concrete stem wall. Then next to that is just a regular stud wall (i.e. no stem wall there). Each of these has a window in the middle of it too.
- So, I don't see any way to easily do an earthquake retrofit on that wall - I'd have to tear the entire wall out & make it into a shear wall by working around those windows somehow, then sheetrock it back up.

[look 171]

Shear your "Pony wall". Make sure you drill 3/4 or 1" holes every 8 or so inches apart. that allows for air circulation.

[RWebb]

got any ideas about how to deal with this one?

there is only 10 mm clearance to the joist and almost no way to get in there to do anything - if I chisel into the rim joist, it will take hours and weaken the joist in that spot

[Zeke]

It won't take hours. What I do is cut a side off the washer so that it still goes under the board an 1/8th or more. I might chisel out a small wedge and let the washer crush its way in. No need to spare the threads when installing. Boogered threads don't work loose.

Or take a flat bar and slap the edge of the washer to push it under.

You're taking this wood butchering thing a bit too far. This ain't a clock. Slam that sch!t together and be done.


BTW, another thing you could do there is install an angle. Cinch it down and run a couple of short lags horizontally into the joist, or rim joist. Now you've tied 2 pieces together and to the foundation.

[RWebb]

yeh - considering my past lives, I may be a little too far out on structural carpentry

BUT, Simpson makes the plates real real thick (nearly 1/4" thick) and they are very particular about how you do stuff (to maintain earhquake resiliency)

for example, if you use one of their plates with an oblong hole in it, you have to use a spec'd washer (A! whatever that is) on top of it and they also want you to do some juju re placement & etc.

so, if I cut their plate with a hacksaw, will it still be adequate in an earthquake??? if not, then I may as well just use a small and thin washer, right?

there is a lot less space to work in there than it looks like - I already chiseled out 2 other spots to get the things in but this one has less space than either & less room to work

I did spend a while at 2 places looking at angle connectors, but saw nothing that would work...

only other idea I have is even more work - that would be to tie the mud sill down to the concrete wall by ripping out the sheet rock in one spot; then hammering in an angle on the outside (i.e. not tying the mud sill and rim joist together, but the mud sill to the concrete wall

thoughts?

[Zeke]

The washer cut off on one side still holds down the same amount in 3 directions and a percentage in the 4th dimension. Jeez, what more could you need given the circumstances?

You have to realize that Simpson has over engineered every spec they cite. It's like a ladder rated at 300 lbs. Are you serious? You could put double that on it but they have to consider the idiot that would try to set up and climb the thing at a 45° angle (see that?! I made a symbol )

Simpson is CA based starting out in San Francisco earthquake country. They have worked extensively with the Los Angeles building and safety product testing lab and obtaining approved ratings with certification. It's so freakin' over engineered that it is just nuts.

Your house bolting and bracing project is a whole, not some bolts here and there. In fact, you could do more damage by doing it wrong. However, what you show here can be done with a larger washer and that's it. Even if one side is clipped.

And why do they now use square washers? Surface area. A round washer would produce less stress at the perimeter, but to get equal perimeter and surface area, it would be a lot larger. Think material waste in manufacturing.

[turbo6bar]

I would hack away some of the rim joist to permit a full washer to be used. Is there enough thread exposed to actually get a nut on more than a few turns?

I'd use a sawzall with a stiff 6" blade or if you can get your head up there to see, a sharp chisel and hammer will do. Pretty is the enemy of good enough.

I don't see how a piece of angle will do. If you can get a piece of angle secured, you can get a bolt and washer down. However, don't forget the load path. Securing the sill isn't doing you much. Tie the rim joist to the sill. Then, how do you tie the bottom plate to the rim joist without tearing out plaster/wallboard? It's a slippery slope.

That said, if you can get the sill bolted down, I like Zeke's idea with the pieces of angle iron. 3/16" thick angle + 1.5" sill/joist + a washer would let you use a 2" lag screw. Use a cordless impactor to shoot the lags down, and now the rim joist is tied to the sill.

Simpson also makes angle structural ties. Grab a palm nailer and a box of 10 penny nails and go to town. It'd be faster if you don't have an easy way to drill angle iron.

Aren't rafter ties spaced at 48" on-center? If so, there's your spacing.
jurgen

[john70t]

There are 4 things I didn't like about that rim joist pic:

1). The sill-plate bolt/stud is rusting and dry.
A quick spray of WD-40 is better than nothing.

2). The connection doesn't look substantial.
The bolt seems too short and close to the edge. Washer edges may have have to be ground down to fit. I'd prefer crushing the top 1/4in of wood as opposed to removing it, if possible.
Oiled wood never hurts nothing 'cept in fire.

3). Where is the rim joist insulation?
Approximately 25-30% of building heat loss is sucked up through the concrete basement walls to above the frost line and exists the enclosure.

4). There is a huge "wet spot" on the rim joist to the right.
Where is that water coming from? Fix it now.

[look 171]

Try this little guy. Simpson Strong-Tie UFP10-SDS3 (Priced as Eaches - Full Box Count 10) - Fastening Systems Inc. It is approved in LA. I would install Simpson's A35 on all the joist that connect to the plate. Look up A35s and their applications under there. I am dealing with a foundation on the hill side now. I will try and shoot a couple of pic for you when we get all the clips in place. We are such wusses, it might rain in the next few days, so my men be no trabajo (sp?).

[RWebb]

1. is the rust all that bad?

2. that stud is long enuff to take a nut + a Simpson Bearing Plate -- at least the other ones were; see pic up higher in the thread for one of the other studs

3. there was none - I will insulate with spray foam and then batts after I get the thing tied down
on one of the other places along this rim joist I could look out and see daylight, BTW

4. no wet spots - maybe you are seeing where the wash of gray paint ends?

I could go with the UFP10 connectors - but then I have to drill into the concrete stem wall - also, how would I hide the things? The sheetrock will not cover them, and I'd like the room to look halfway decent when done...

I cannot get sawzall with a stiff 6" blade in there. I could maybe get sawzall with a flexible 6" blade in and then use it to cut a sort of arc out of the rim joist. I bet it will not work and just make me cuss a lot, but I could try...

[RWebb]

or maybe I could use one of those side-cutting drill bits to rip away some of the wood on the rim joist??

[look 171]

Ok, I see that it will be a finish room. Forget about the UFP clips. don't worry about the rust. Crank the nuts in there and be done with it. It will be there for a loooong time. Take a chisel and an hammer and give it a good whack. Get a little of the washer under there and be done with it. Like Milt said, cut off the washer a little bit and put it in there. Do not be gentle with it. You do not need to. None of it is seen once its cover up with drywall. I see this will be a finish basement? shear the entire wall and sheet rock on top of that (No structural calc?). Another solution is to chisel out a little of the lumber on the plate and gain a little room for the washer and the nut. A little more thread is needed on that last photo. Not a big deal really

Like I said earlier, do not use that expansion foam to fill the hole. it will retain water. fix the hole and make sure its water tight, then you can spray all the foam to your heart content. Is it wood siding on the exterior or stucco? Stucco common up in OR?

[RWebb]

wood siding above, but it sits on the rim joist

I'll see what I can do about carving into the interior side of it, but ...