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Attaching sill plates to foundations


drw
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Does anyone know when the practice of attaching sill plates to foundations with bolts or straps became common practice?

The vast majority of 50+ year old homes I see do not have anchors, so I'm guessing the requirement came after that.

Do any of you call out their absence on older homes?

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Hi,

I don't know when it became commonplace. My guess, since I remember seeing my Dad putting them in as far back as the 50's and since I don't usually see them in pre-WWII stock, is around the mid 1940's.

I educate clients about the fact that older homes in this region very rarely have foundation bolts. Since I'm in an active seismic zone (we had one last week) I generally recommend that from a common sense standpoint it's prudent to at least have seismic bracing added and point out that without it they probably won't be able to get earthquake coverage here. They can draw their own conclusions from there.

When they want to know how effective seismic bracing will be, I flat out tell them that I don't really know. It's going to depend on so many variables that I couldn't possibly predict, and on just how far they go to brace the home. Some folks add just foundation bolts, others strap the floor platform down to the foundation, strap the upper floors to lower and add plywood sheathing over all of the basement cripple walls to stiffen things up. Others don't do anything and the house has stood up fine to earthquakes for up to a century, so there's no predicting it. It's my belief that nothing - not even tons of seismic bracing and least of all foundation bolts - is really going to do a whole lot of good when "The Big One," that seismologists on the west coast have been expecting for nearly a century, finally hits.

Anyway, you weren't asking about seismic bracing, so I apologize for the ramble. I think adding foundation bolts after the fact in an older home is one of those things you can recommend but can be perceived as a buckethead recommendation - especially if the home is a nearly 100-year old bungalow that is as straight, square and tight as the day it was built and it has never budged an inch. I suppose it does make sense in flood zones though - ala Katrina's floating homes - but otherwise making such a recommendation might make it look like you are stretching to find something to write up.

I say write them up if there is damage or shifting caused by their absence, or the home is in a flood zone, and recommend them simply as a common sense measure otherwise.

ONE TEAM - ONE FIGHT!!!

Mike

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This is interesting?

When I was taking architecture, all details always showed anchor bolts through sill plates with washers and nuts. Those books were circa 1940s. In the Richmond area, most old buildings are solid masonry with firecut joists in pockets. But, most old frame houses here usually have either bolts or 1/8" strap iron anchors. Not seeing anchors at all here would be very rare.

It was common in older homes (you know back when architects thought of just about everything) to nicely countersink the washer and nut. You might feel along the top of the sill and make sure that isn't the case. AS a mason, we used to carefully measure our bolt heights for countersinks when called for.

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Yep,

Felt up a whole lot of sills around here. Still didn't find any bolts though. Randy, it was up near Marysville/Tulalip or thereabouts. I didn't feel it either but folks up that way sure did. It was all over the evening news. It's amazing the number of quakes we do experience here that we don't know about. I once went to that website where UW records all of the local quakes, just to check on the date of one which I did feel, and found that there'd been about half a dozen over a two month period that I hadn't even been aware of. I guess the only ones that make the news are the ones which knock people about and such.

OT - OF!!!

M.

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Does anyone know when the practice of attaching sill plates to foundations with bolts or straps became common practice?

Around here it seems to coincide with the transition from balloon to platform framing and cmu foundations.

Do any of you call out their absence on older homes?

The ground doesn't move here and we don't get winds that will move a building (maybe a carport).

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We're kinda at the tail end of tornado alley, and we get our share each year. One of my Clients was a meteoroligist (a real one, not a TV line-reading one). She told me 90-some-percent of tornados are F1's ane F2's. Knowing quite a bit about tornado damage, she indicated the sill bolts do a fine job of holding down a house during F1's or F1's. I use this info when the RealtorZoid says the house has been fine without them for X number of years.

I would love to see stats on a neighborhood that was hit by an F1 or a F2...which houses had sill bolts, which didn't, and which ones stayed put.

Sill bolts just ain't for seismic reasons.

'Course, my Client did indicate that F3's or bigger..."Run".

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