How does the house know which rules to break and which ones not to break? Take foundation bolting for example. It is a question I get asked often----is the house bolted to the foundation? Over the course my building career I have seen foundation bolting go from ½” bolts, 6-8 feet apart, with no washers under the nuts, to 5/8” bolts, every four feet, with 2” square-plate washers under the nuts. In addition to this bolting are all manner of seismic strapping and hold-down bracketss with bolts as big as 1-1/8” in diameter. And this is in residential construction----commercial is even more extensive. All of this is fine and dandy and will likely help your house do very well in seismic activity up to a 7 or a little higher on the Richter scale. After that, all bets are off supposedly----but still the amount of damage would have to be somewhat less. Again I ask, “How does the house know which rules to break and which ones not to break? You see, the other day, I inspected a house that was over 30 years old. Its age tells me that it has been through at least two fairly major earthquakes in this region-----including the 2001 Nisqually Quake. The house had no visible damage and yet the foundation bolting---while present----looked like the following picture. This bolting is almost worse than no bolting at all----as the sill plates are nearly completely severed every 6 feet. So the insurance company wants to know if the house is bolted. Any inspector would be “nuts” to say that this foundation is “bolted” wouldn’t they? And yet the house is doing fine after 30 years and is “standing the test of time.” The house has broken the “rules” and is doing fine. Keeping houses on their foundations is not restricted to or dependent on code requirements for bolting. There are many older homes in Seattle that are not bolted to their foundations at all and have little or no seismic damage going back to earthquakes even stronger than any this house wiggled through. For example there was a method of pouring foundations in this area, that used to be very common, where the bottom plate of the wall was put right in the forms so that when the concrete was poured it actually came up higher on the plate all the way around the inside of the foundation. This created an installation where the wood walls were naturally locked in place laterally by the concrete wall itself. As you can see, answering the seemingly simple question of whether the foundation is bolted or not does not really provide much in the way real information to anyone. How the house is performing in relation to its age and methods of bolting is much more useful information to provide. Charles Buell, Seattle Home Inspector
In my many years as a builder----and in my more recent incarnation as a Seattle Home Inspector-----something that I have noticed about houses is that they can be very forgiving structurally. Complete structural failure of a component is sometimes difficult to arrange. Other times, with the requisite conditions, we will see the weekend warrior’s deck go all kittywampus in the back yard----with the beer keg rolling down the street as the ambulance pulls into the driveway.
The reason this 30 year old house has done so well is because of the many “steps” in the foundation. Stepping the foundation aids in interlocking the foundation and wood walls, thus restricting movement laterally. If we take the same house with a uniform foundation---with no steps-----and did the same type of bolting as in the second picture, the house would likely not fare as well.
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The first picture was about to make me bolt for the bathroom. I'm sure the framers would have blamed the cement guys and the general (probably the carpenter) just said go ahead and make it work.
Interesting stuff, Charles. I think I probably learn more reading your stuff than just about anybody. Perhaps that has to do with my extreme lack of knowledge in these areas or the very articulate manner in which you share the information. Perhaps a bit of both:)
fortunately, one thing that we do not require, here in the midwest.
But some underwriter just wants to see the check in the proper box. Great post!
Charlie,
Bolting is often talked about in Don at NCW Home Inspections and myself. I think as you said the way the home is performing in relation to its age is important. I often inspect homes 60 to 100 years old that are holding up very well for their age. Hope I will do as well :)
Great post. Good information. But I'm awfully glad I don't have to deal much with seismic requirements.
Hi Charles, great info. I had not seen the stepping on a foundation before. Thanks for sharing.
Glenn, I am sure the the concrete guys screwed up----but the framers should have properly extended the bolts----enough blame to go around I am sure
Jason, always trying to inform as opposed to conform :)
Alan, I am sure you have some amount of bolting there---just not as extensive as here.
Doug, most likely
Dennis, a lot of older homes were more "flexible" than newer homes which makes them naturally better protected
Dale, I think it is a regional thing
Charles - Great illustrations of the what's and why's of foundation bolting. Here in the south we're not troubled by seismic activity, but are required to use "hurricane" straps to secure the sill plate. However, we're too far from the sea for significant hurricane damage, but we are regularly plagued by tornadoes. When one hits, the sill plate is always left securely fastened to the foundation, but the house may be scattered over several miles.
C'mon, there's plenty left to that thing! It looks like the foundation bolter only had short ones on his truck that day. Around here only detached garages are bolted. Foundations are typically strapped.
I'm more of a dog man, so I hope my deck goes doggiewampus. But that is just me.
John, I can imagine----protection against overturning is a good plan for most areas of the country
Jay, not both?
May be time to recommend a structural engineer take a look and offer some suggestions.
Charles - Interestingly, my reaction after reading this post was the same as Jason Sardi's. I think I learn more stuff from you than just about anyone on AR. Thanks for sharing your knowledge. :)
Charles:
Terrific post! You are my new building educator!!!
Blake
Charles: Ditto the Jasons' That is a tough question, the: "Is this a problem?" Well kind-of yes and kind-of no.
Where are all of the hard and fast rules? I give up...till tomorrow.
Charlie,
That is a really nice blogpost. Congrats on the feature.
Hi Charles -- Absolutely fascinating. One would think even from a common sense standpoint not to cut out a section of a sill plate, but go through the top with a longer bolt?
Carl & Ceil, as a home inspector, I don't have much choice do I :)
Michael, silly me----of course
Jason, you and that other Jason guy are too kind----thanks :)
Blake, glad I could be of help---thanks
Jim, a black & white world would be SOOOO much easier :)
Steve, has Nutsy got the night off?
Chris, if only common sense was common
Charles,
The one that I like is when they don't think ahead and place the bolts in the concrete right where the studs will end up.
OMG, I am just giggling looking at the pictures... I thought the first was bad, then I saw the second one!
Charles, Yikes, looks like that was done on a Friday.
Charles:
This is really getting to the heart of the matter. Will this house stand the test of time and possible earthquakes?
I find it interesting that you take so many photos of your inspections. I wish more inspectors did that.
Charles...
We don't have much seismic activity is our area, but we are in tornado alley and thus secure foundation ties are essential to keeping the house from moving. Great explanation!
Charles, standing the test of time should have some merit. How much time will it stand though. Good explanation. Thanks.
I haven't seen anything like that around here, but then again I don't look at too many foundations. Michael at #13, that was hilarious!
Terry, yes, that happens too-----much easier to deal with than this though :)
Chris, yes as bad as the first picture looks it was a relatively simple fix.
David, that sounds about right
Claudette, pictures are my only note-taking tool----I rarely have to get out my pen and write something down.
Richard, in some ways keeping houses held down for tornadoes is more difficult than dealing with earthquakes
Michael, the great unknown question :)
Darrell, I don't think I have ever seen anyone screw up bolting quite as bad as this.
I find this subject facinating because it points out how absolutely different building practices are from one region to another, and why. Here in Houston, yes, we worry about hurricanes, but that mostly affects how we attach the roof, (with hurricane clips). What is actually a much bigger issue is we have to worry about is shifting soil, due to our lack of rock understructure with the subservice soil, (which we call "gumbo clay"). We must build our foundations to hold up to the expansions and shrinking of the clay. Yet still, the most common and most expensive issue a homeowner will have around here is a broken slab that requires expensive repairs to re-level the house.
I am working with many buyers that are relocating to Houston because of jobs. I must keep the differences of building practices in mind. Actually, the one that shocks most people is that we don't do basements in Houston do to the nature of the clay substructure and the high water tables. When they ask where the basement is I point up and say, we have aggie basements around here. (referring to the attic).
It never ceases to amaze me what is discovered during the property inspection.
I learn something from you on every post! Thanks for the education!
Amy, you are so right----expansive clays can be some of the most difficult site conditions to deal with.
Stewart----makes for never a dull moment as an inspector----and the agents that have to deal with what we find :)
Gabrielle, glad you find them useful
Expansive clay and settling are a big concern in my neck of the woods. "Floating walls" is the norm and sometimes that is not enough.
Charles,
As always, good "stuff" Bro!
Brian, are you talking about "floating slabs?" I hear they are pretty effective.
Peter, thanks---nice to see you back playing in the rain :)
Boy...whatever is causing those problems sure eats well..........
Richie, the first photo is just good ole decay/rot
Mr Charles,
As a recording star, used to being pampered, I would have bolted from that crawling space.
Wheatloaf, Nutsy's cousin
Charles,
It amazing me how two areas- Western Wa and Eastern Wa- can have such differences and we are only 150 to 200 miles apart. Still need bolts though! I was in a new home and could not see one bolt. My guess was they where buried under the bottom plate, but I could not verify. Always fun in crawlspaces.
Love the first post photo, Mr Rotty go at it again.
Don
Wheatforbrains---I imagine you would
Don, those doulbe plates can be as useless as the one I pictured.
So is it a problem? As an inspector yes it most certainly is. As an observer no, like you say the house and structure are functioning. BUT there is no need to tempt the fickle finger of fate. The house could be the next lucky lottery winner. It should be repaired.
Jim, certainly not my job to say it is NOT a problem----certainly should be repaired.
That is some really good information but it brings up an interesting dilemma home inspectors face. The inspector can report a structural concern (like the severely notched bottom plate shown in your photo) but he may be criticised (usually by the agents or the seller) because the component has not failed. "It is still working so it is not a problem." But to those of us who understand the structure we know the component is likely to fail when loaded under the right conditions (e.g., an earthquake).
To make an analogy, what if a mechanic checked the driver's air bag in a used car you are considering buying and stated the bag was installed incorrectly and may not deploy in a serious crash. The used car salesman may waive his arms and scream that the air bag has not failed and the cover over the air bag looks good so there is no problem. Would you ignore the mechanic's advice or request the air bag be repaired?
Bruce, it is all a function of scale I guess when it comes to defining "working." The roof attachment worked until that Category 5 hit :)